WHAT IF Check report

This file was created 2012-01-04 from WHAT_CHECK output by a conversion script. If you are new to WHAT_CHECK, please study the pdbreport pages. There also exists a legend to the output.

Please note that you are looking at an abridged version of the output (all checks that gave normal results have been removed from this report). You can have a look at the Full report instead.

Verification log for pdb1l9m.ent

Non-validating, descriptive output paragraph

Note: Ramachandran plot

In this Ramachandran plot x-signs represent glycines, squares represent prolines, and plus-signs represent the other residues. If too many plus- signs fall outside the contoured areas then the molecule is poorly refined (or worse). Proline can only occur in the narrow region around phi=-60 that also falls within the other contour islands.

In a colour picture, the residues that are part of a helix are shown in blue, strand residues in red. Preferred regions for helical residues are drawn in blue, for strand residues in red, and for all other residues in green. A full explanation of the Ramachandran plot together with a series of examples can be found at the WHAT_CHECK website.

Chain identifier: A

Note: Ramachandran plot

Chain identifier: B

Coordinate problems, unexpected atoms, B-factor and occupancy checks

Warning: What type of B-factor?

WHAT IF does not yet know well how to cope with B-factors in case TLS has been used. It simply assumes that the B-factor listed on the ATOM and HETATM cards are the total B-factors. When TLS refinement is used that assumption sometimes is not correct. TLS seems not mentioned in the header of the PDB file. But anyway, if WHAT IF complains about your B-factors, and you think that they are OK, then check for TLS related B-factor problems first.

Obviously, the temperature at which the X-ray data was collected has some importance too:

Temperature cannot be read from the PDB file. This most likely means that the temperature is listed as NULL (meaning unknown) in the PDB file.

Note: B-factor plot

The average atomic B-factor per residue is plotted as function of the residue number.

Chain identifier: A

Note: B-factor plot

Chain identifier: B

Nomenclature related problems

Warning: Arginine nomenclature problem

The arginine residues listed in the table below have their N-H-1 and N-H-2 swapped.

 553 ARG   ( 570-)  A
 570 ARG   ( 587-)  A
1234 ARG   ( 570-)  B
1251 ARG   ( 587-)  B

Warning: Tyrosine convention problem

The tyrosine residues listed in the table below have their chi-2 not between -90.0 and 90.0

 312 TYR   ( 312-)  A
 346 TYR   ( 346-)  A
 401 TYR   ( 401-)  A
 421 TYR   ( 421-)  A
 508 TYR   ( 525-)  A
 545 TYR   ( 562-)  A
 915 TYR   ( 240-)  B
1021 TYR   ( 346-)  B
1096 TYR   ( 421-)  B
1116 TYR   ( 441-)  B
1189 TYR   ( 525-)  B
1226 TYR   ( 562-)  B

Warning: Phenylalanine convention problem

The phenylalanine residues listed in the table below have their chi-2 not between -90.0 and 90.0.

  14 PHE   (  14-)  A
  24 PHE   (  24-)  A
 117 PHE   ( 117-)  A
 177 PHE   ( 177-)  A
 198 PHE   ( 198-)  A
 364 PHE   ( 364-)  A
 662 PHE   ( 679-)  A
 689 PHE   (  14-)  B
 699 PHE   (  24-)  B
 792 PHE   ( 117-)  B
 852 PHE   ( 177-)  B
 873 PHE   ( 198-)  B
1039 PHE   ( 364-)  B
1343 PHE   ( 679-)  B

Warning: Aspartic acid convention problem

The aspartic acid residues listed in the table below have their chi-2 not between -90.0 and 90.0, or their proton on OD1 instead of OD2.

 141 ASP   ( 141-)  A
 183 ASP   ( 183-)  A
 245 ASP   ( 245-)  A
 301 ASP   ( 301-)  A
 324 ASP   ( 324-)  A
 493 ASP   ( 510-)  A
 549 ASP   ( 566-)  A
 627 ASP   ( 644-)  A
 642 ASP   ( 659-)  A
 816 ASP   ( 141-)  B
 858 ASP   ( 183-)  B
 903 ASP   ( 228-)  B
 920 ASP   ( 245-)  B
 995 ASP   ( 320-)  B
 999 ASP   ( 324-)  B
1174 ASP   ( 510-)  B
1230 ASP   ( 566-)  B
1243 ASP   ( 579-)  B
1308 ASP   ( 644-)  B
1323 ASP   ( 659-)  B

Warning: Glutamic acid convention problem

The glutamic acid residues listed in the table below have their chi-3 outside the -90.0 to 90.0 range, or their proton on OE1 instead of OE2.

 152 GLU   ( 152-)  A
 153 GLU   ( 153-)  A
 157 GLU   ( 157-)  A
 254 GLU   ( 254-)  A
 391 GLU   ( 391-)  A
 462 GLU   ( 479-)  A
 515 GLU   ( 532-)  A
 529 GLU   ( 546-)  A
 827 GLU   ( 152-)  B
 828 GLU   ( 153-)  B
 832 GLU   ( 157-)  B
 856 GLU   ( 181-)  B
 929 GLU   ( 254-)  B
1066 GLU   ( 391-)  B
1138 GLU   ( 474-)  B
1141 GLU   ( 477-)  B
1161 GLU   ( 497-)  B
1196 GLU   ( 532-)  B
1210 GLU   ( 546-)  B
1211 GLU   ( 547-)  B
1250 GLU   ( 586-)  B

Geometric checks

Warning: Possible cell scaling problem

Comparison of bond distances with Engh and Huber [REF] standard values for protein residues and Parkinson et al [REF] values for DNA/RNA shows a significant systematic deviation. It could be that the unit cell used in refinement was not accurate enough. The deformation matrix given below gives the deviations found: the three numbers on the diagonal represent the relative corrections needed along the A, B and C cell axis. These values are 1.000 in a normal case, but have significant deviations here (significant at the 99.99 percent confidence level)

There are a number of different possible causes for the discrepancy. First the cell used in refinement can be different from the best cell calculated. Second, the value of the wavelength used for a synchrotron data set can be miscalibrated. Finally, the discrepancy can be caused by a dataset that has not been corrected for significant anisotropic thermal motion.

Please note that the proposed scale matrix has NOT been restrained to obey the space group symmetry. This is done on purpose. The distortions can give you an indication of the accuracy of the determination.

If you intend to use the result of this check to change the cell dimension of your crystal, please read the extensive literature on this topic first. This check depends on the wavelength, the cell dimensions, and on the standard bond lengths and bond angles used by your refinement software.

Unit Cell deformation matrix

 |  0.999028  0.000099 -0.000055|
 |  0.000099  0.999674  0.000117|
 | -0.000055  0.000117  0.998579|
Proposed new scale matrix

 |  0.017345  0.002641  0.000387|
 | -0.000001  0.014988  0.001933|
 |  0.000000 -0.000001  0.008689|
With corresponding cell

    A    =  57.654  B   =  67.489  C    = 116.035
    Alpha=  97.235  Beta=  90.154  Gamma=  98.653

The CRYST1 cell dimensions

    A    =  57.709  B   =  67.515  C    = 116.208
    Alpha=  97.240  Beta=  90.150  Gamma=  98.670

Variance: 40.142
(Under-)estimated Z-score: 4.669

Warning: Unusual bond angles

The bond angles listed in the table below were found to deviate more than 4 sigma from standard bond angles (both standard values and sigma for protein residues have been taken from Engh and Huber [REF], for DNA/RNA from Parkinson et al [REF]). In the table below for each strange angle the bond angle and the number of standard deviations it differs from the standard values is given. Please note that disulphide bridges are neglected. Atoms starting with "-" belong to the previous residue in the sequence.

 507 ILE   ( 524-)  A      N    CA   C    99.72   -4.1
 993 PRO   ( 318-)  B      N    CA   C   101.66   -4.1
1188 ILE   ( 524-)  B      N    CA   C    99.79   -4.1

Error: Nomenclature error(s)

Checking for a hand-check. WHAT IF has over the course of this session already corrected the handedness of atoms in several residues. These were administrative corrections. These residues are listed here.

 141 ASP   ( 141-)  A
 152 GLU   ( 152-)  A
 153 GLU   ( 153-)  A
 157 GLU   ( 157-)  A
 183 ASP   ( 183-)  A
 245 ASP   ( 245-)  A
 254 GLU   ( 254-)  A
 301 ASP   ( 301-)  A
 324 ASP   ( 324-)  A
 391 GLU   ( 391-)  A
 462 GLU   ( 479-)  A
 493 ASP   ( 510-)  A
 515 GLU   ( 532-)  A
 529 GLU   ( 546-)  A
 549 ASP   ( 566-)  A
 553 ARG   ( 570-)  A
 570 ARG   ( 587-)  A
 627 ASP   ( 644-)  A
 642 ASP   ( 659-)  A
 816 ASP   ( 141-)  B
 827 GLU   ( 152-)  B
 828 GLU   ( 153-)  B
 832 GLU   ( 157-)  B
 856 GLU   ( 181-)  B
 858 ASP   ( 183-)  B
 903 ASP   ( 228-)  B
 920 ASP   ( 245-)  B
 929 GLU   ( 254-)  B
 995 ASP   ( 320-)  B
 999 ASP   ( 324-)  B
1066 GLU   ( 391-)  B
1138 GLU   ( 474-)  B
1141 GLU   ( 477-)  B
1161 GLU   ( 497-)  B
1174 ASP   ( 510-)  B
1196 GLU   ( 532-)  B
1210 GLU   ( 546-)  B
1211 GLU   ( 547-)  B
1230 ASP   ( 566-)  B
1234 ARG   ( 570-)  B
1243 ASP   ( 579-)  B
1250 GLU   ( 586-)  B
1251 ARG   ( 587-)  B
1308 ASP   ( 644-)  B
1323 ASP   ( 659-)  B

Error: Tau angle problems

The side chains of the residues listed in the table below contain a tau angle (N-Calpha-C) that was found to deviate from te expected value by more than 4.0 times the expected standard deviation. The number in the table is the number of standard deviations this RMS value deviates from the expected value.

 947 CYS   ( 272-)  B    6.21
 272 CYS   ( 272-)  A    5.55
1345 ALA   ( 681-)  B    5.06
 907 LEU   ( 232-)  B    4.86
 232 LEU   ( 232-)  A    4.69
 664 ALA   ( 681-)  A    4.62
 993 PRO   ( 318-)  B    4.38
1098 SER   ( 423-)  B    4.26
 318 PRO   ( 318-)  A    4.02

Torsion-related checks

Warning: Torsion angle evaluation shows unusual residues

The residues listed in the table below contain bad or abnormal torsion angles.

These scores give an impression of how `normal' the torsion angles in protein residues are. All torsion angles except omega are used for calculating a `normality' score. Average values and standard deviations were obtained from the residues in the WHAT IF database. These are used to calculate Z-scores. A residue with a Z-score of below -2.0 is poor, and a score of less than -3.0 is worrying. For such residues more than one torsion angle is in a highly unlikely position.

 977 THR   ( 302-)  B    -3.3
1319 ARG   ( 655-)  B    -2.5
 528 GLU   ( 545-)  A    -2.3
 979 ARG   ( 304-)  B    -2.2
  81 GLY   (  81-)  A    -2.2
1209 GLU   ( 545-)  B    -2.2
 424 THR   ( 424-)  A    -2.1
1137 LEU   ( 473-)  B    -2.1
 683 ILE   (   8-)  B    -2.1
1265 LEU   ( 601-)  B    -2.1
1297 GLY   ( 633-)  B    -2.1
 853 GLY   ( 178-)  B    -2.1
 616 GLY   ( 633-)  A    -2.1
 650 THR   ( 667-)  A    -2.1
1012 PHE   ( 337-)  B    -2.1
1099 THR   ( 424-)  B    -2.1
1144 PRO   ( 480-)  B    -2.0
 286 LEU   ( 286-)  A    -2.0
 400 LEU   ( 400-)  A    -2.0

Warning: Backbone evaluation reveals unusual conformations

The residues listed in the table below have abnormal backbone torsion angles.

Residues with `forbidden' phi-psi combinations are listed, as well as residues with unusual omega angles (deviating by more than 3 sigma from the normal value). Please note that it is normal if about 5 percent of the residues is listed here as having unusual phi-psi combinations.

  20 HIS   (  20-)  A  Poor phi/psi
  68 MET   (  68-)  A  Poor phi/psi
  80 SER   (  80-)  A  Poor phi/psi
 164 VAL   ( 164-)  A  Poor phi/psi
 183 ASP   ( 183-)  A  Poor phi/psi
 227 ASP   ( 227-)  A  Poor phi/psi
 264 LEU   ( 264-)  A  Poor phi/psi
 268 ARG   ( 268-)  A  omega poor
 297 ASN   ( 297-)  A  Poor phi/psi
 361 GLN   ( 361-)  A  Poor phi/psi
 367 GLY   ( 367-)  A  PRO omega poor
 382 ASN   ( 382-)  A  omega poor
 528 GLU   ( 545-)  A  Poor phi/psi
 550 ASN   ( 567-)  A  Poor phi/psi
 562 ASP   ( 579-)  A  Poor phi/psi
 585 ASN   ( 602-)  A  Poor phi/psi
 590 ARG   ( 607-)  A  Poor phi/psi
 634 LYS   ( 651-)  A  Poor phi/psi
 695 HIS   (  20-)  B  Poor phi/psi
 743 MET   (  68-)  B  Poor phi/psi
 755 SER   (  80-)  B  Poor phi/psi
 756 GLY   (  81-)  B  Poor phi/psi
 757 GLY   (  82-)  B  Poor phi/psi
 853 GLY   ( 178-)  B  Poor phi/psi
 858 ASP   ( 183-)  B  Poor phi/psi
 902 ASP   ( 227-)  B  Poor phi/psi
 903 ASP   ( 228-)  B  Poor phi/psi
 939 LEU   ( 264-)  B  Poor phi/psi
 943 ARG   ( 268-)  B  omega poor
 972 ASN   ( 297-)  B  Poor phi/psi
 976 ASP   ( 301-)  B  Poor phi/psi
 980 ASN   ( 305-)  B  Poor phi/psi
1007 TRP   ( 332-)  B  Poor phi/psi
1036 GLN   ( 361-)  B  Poor phi/psi
1042 GLY   ( 367-)  B  PRO omega poor
1057 ASN   ( 382-)  B  omega poor
1134 LEU   ( 459-)  B  Poor phi/psi
1141 GLU   ( 477-)  B  Poor phi/psi
1145 SER   ( 481-)  B  Poor phi/psi
1172 SER   ( 508-)  B  Poor phi/psi
1173 ARG   ( 509-)  B  Poor phi/psi
1175 THR   ( 511-)  B  Poor phi/psi
1200 ASP   ( 536-)  B  Poor phi/psi
1209 GLU   ( 545-)  B  Poor phi/psi
1243 ASP   ( 579-)  B  Poor phi/psi
1266 ASN   ( 602-)  B  Poor phi/psi
1271 ARG   ( 607-)  B  Poor phi/psi
1315 LYS   ( 651-)  B  Poor phi/psi
1345 ALA   ( 681-)  B  Poor phi/psi
 chi-1/chi-2 correlation Z-score : -1.387

Warning: Unusual rotamers

The residues listed in the table below have a rotamer that is not seen very often in the database of solved protein structures. This option determines for every residue the position specific chi-1 rotamer distribution. Thereafter it verified whether the actual residue in the molecule has the most preferred rotamer or not. If the actual rotamer is the preferred one, the score is 1.0. If the actual rotamer is unique, the score is 0.0. If there are two preferred rotamers, with a population distribution of 3:2 and your rotamer sits in the lesser populated rotamer, the score will be 0.667. No value will be given if insufficient hits are found in the database.

It is not necessarily an error if a few residues have rotamer values below 0.3, but careful inspection of all residues with these low values could be worth it.

 861 SER   ( 186-)  B    0.36
 285 SER   ( 285-)  A    0.37
 741 SER   (  66-)  B    0.39
 960 SER   ( 285-)  B    0.39

Warning: Unusual backbone conformations

For the residues listed in the table below, the backbone formed by itself and two neighbouring residues on either side is in a conformation that is not seen very often in the database of solved protein structures. The number given in the table is the number of similar backbone conformations in the database with the same amino acid in the centre.

For this check, backbone conformations are compared with database structures using C-alpha superpositions with some restraints on the backbone oxygen positions.

A residue mentioned in the table can be part of a strange loop, or there might be something wrong with it or its directly surrounding residues. There are a few of these in every protein, but in any case it is worth looking at!

   3 LEU   (   3-)  A      0
   6 GLN   (   6-)  A      0
  10 TRP   (  10-)  A      0
  20 HIS   (  20-)  A      0
  21 THR   (  21-)  A      0
  22 ASP   (  22-)  A      0
  24 PHE   (  24-)  A      0
  25 SER   (  25-)  A      0
  26 SER   (  26-)  A      0
  27 GLN   (  27-)  A      0
  33 ARG   (  33-)  A      0
  43 MET   (  43-)  A      0
  51 GLU   (  51-)  A      0
  59 THR   (  59-)  A      0
  63 PRO   (  63-)  A      0
  68 MET   (  68-)  A      0
  69 THR   (  69-)  A      0
  70 LYS   (  70-)  A      0
  77 ASN   (  77-)  A      0
  80 SER   (  80-)  A      0
  83 TRP   (  83-)  A      0
  88 GLN   (  88-)  A      0
  89 ALA   (  89-)  A      0
  91 ASN   (  91-)  A      0
  93 ASN   (  93-)  A      0
And so on for a total of 562 lines.

Warning: Omega angles too tightly restrained

The omega angles for trans-peptide bonds in a structure are expected to give a gaussian distribution with the average around +178 degrees and a standard deviation around 5.5 degrees. These expected values were obtained from very accurately determined structures. Many protein structures are too tightly restrained. This seems to be the case with the current structure too, as the observed standard deviation is below 4.0 degrees.

Standard deviation of omega values : 1.288

Warning: Backbone oxygen evaluation

The residues listed in the table below have an unusual backbone oxygen position.

For each of the residues in the structure, a search was performed to find 5-residue stretches in the WHAT IF database with superposable C-alpha coordinates, and some restraining on the neighbouring backbone oxygens.

In the following table the RMS distance between the backbone oxygen positions of these matching structures in the database and the position of the backbone oxygen atom in the current residue is given. If this number is larger than 1.5 a significant number of structures in the database show an alternative position for the backbone oxygen. If the number is larger than 2.0 most matching backbone fragments in the database have the peptide plane flipped. A manual check needs to be performed to assess whether the experimental data can support that alternative as well. The number in the last column is the number of database hits (maximum 80) used in the calculation. It is "normal" that some glycine residues show up in this list, but they are still worth checking!

 616 GLY   ( 633-)  A   2.02   23
1297 GLY   ( 633-)  B   1.91   19

Bump checks

Error: Abnormally short interatomic distances

The pairs of atoms listed in the table below have an unusually short interactomic distance; each bump is listed in only one direction.

The contact distances of all atom pairs have been checked. Two atoms are said to `bump' if they are closer than the sum of their Van der Waals radii minus 0.40 Angstrom. For hydrogen bonded pairs a tolerance of 0.55 Angstrom is used. The first number in the table tells you how much shorter that specific contact is than the acceptable limit. The second distance is the distance between the centres of the two atoms. Although we believe that two water atoms at 2.4 A distance are too close, we only report water pairs that are closer than this rather short distance.

The last text-item on each line represents the status of the atom pair. If the final column contains the text 'HB', the bump criterion was relaxed because there could be a hydrogen bond. Similarly relaxed criteria are used for 1-3 and 1-4 interactions (listed as 'B2' and 'B3', respectively). BL indicates that the B-factors of the clashing atoms have a low B-factor thereby making this clash even more worrisome. INTRA and INTER indicate whether the clashes are between atoms in the same asymmetric unit, or atoms in symmetry related asymmetric units, respectively.

 462 GLU   ( 479-)  A      N   <->  463 PRO   ( 480-)  A      CD     0.30    2.70  INTRA BF
 362 GLY   ( 362-)  A      N   <-> 1365 HOH   ( 982 )  A      O      0.28    2.42  INTRA
 607 VAL   ( 624-)  A      CG1 <->  659 CYS   ( 676-)  A      SG     0.26    3.14  INTRA
1055 GLN   ( 380-)  B      CD  <-> 1133 LYS   ( 458-)  B      NZ     0.25    2.85  INTRA
1155 MET   ( 491-)  B      CG  <-> 1160 LYS   ( 496-)  B      NZ     0.25    2.85  INTRA BF
 257 LYS   ( 257-)  A      NZ  <-> 1365 HOH   ( 988 )  A      O      0.24    2.46  INTRA BL
 872 ASN   ( 197-)  B      ND2 <-> 1366 HOH   ( 732 )  B      O      0.24    2.46  INTRA BL
1071 ARG   ( 396-)  B      NH2 <-> 1250 GLU   ( 586-)  B      OE2    0.24    2.46  INTRA
1055 GLN   ( 380-)  B      OE1 <-> 1133 LYS   ( 458-)  B      NZ     0.23    2.47  INTRA
 814 ASN   ( 139-)  B      ND2 <->  815 VAL   ( 140-)  B      N      0.23    2.52  INTRA BL
 169 ARG   ( 169-)  A      NH2 <->  575 ASP   ( 592-)  A      OD1    0.23    2.47  INTRA
 268 ARG   ( 268-)  A      NE  <-> 1365 HOH   (1018 )  A      O      0.23    2.47  INTRA
 559 LYS   ( 576-)  A      NZ  <->  563 GLU   ( 580-)  A      O      0.22    2.48  INTRA
  65 GLU   (  65-)  A      CD  <-> 1317 ARG   ( 653-)  B      NH1    0.22    2.88  INTRA
 217 ARG   ( 217-)  A      NH2 <->  365 GLN   ( 365-)  A      NE2    0.22    2.63  INTRA
 300 HIS   ( 300-)  A      ND1 <-> 1365 HOH   (1031 )  A      O      0.21    2.49  INTRA
 874 ARG   ( 199-)  B      NH2 <-> 1366 HOH   ( 987 )  B      O      0.21    2.49  INTRA BF
 874 ARG   ( 199-)  B      NE  <-> 1366 HOH   ( 768 )  B      O      0.20    2.50  INTRA
 448 GLU   ( 448-)  A      OE2 <->  449 ARG   ( 449-)  A      NH1    0.20    2.50  INTRA BF
1060 MET   ( 385-)  B      N   <-> 1061 PRO   ( 386-)  B      CD     0.19    2.81  INTRA BL
 396 ARG   ( 396-)  A      NH2 <->  569 GLU   ( 586-)  A      OE2    0.19    2.51  INTRA
 449 ARG   ( 449-)  A      NH2 <-> 1365 HOH   (1050 )  A      O      0.19    2.51  INTRA BF
1119 GLY   ( 444-)  B      N   <-> 1366 HOH   (1106 )  B      O      0.19    2.51  INTRA BF
 978 ASP   ( 303-)  B      N   <-> 1366 HOH   ( 949 )  B      O      0.17    2.53  INTRA BF
  65 GLU   (  65-)  A      OE1 <-> 1317 ARG   ( 653-)  B      NH1    0.17    2.53  INTRA
And so on for a total of 229 lines.

Packing, accessibility and threading

Note: Inside/Outside RMS Z-score plot

The Inside/Outside distribution normality RMS Z-score over a 15 residue window is plotted as function of the residue number. High areas in the plot (above 1.5) indicate unusual inside/outside patterns.

Chain identifier: A

Note: Inside/Outside RMS Z-score plot

Chain identifier: B

Warning: Abnormal packing environment for some residues

The residues listed in the table below have an unusual packing environment.

The packing environment of the residues is compared with the average packing environment for all residues of the same type in good PDB files. A low packing score can indicate one of several things: Poor packing, misthreading of the sequence through the density, crystal contacts, contacts with a co-factor, or the residue is part of the active site. It is not uncommon to see a few of these, but in any case this requires further inspection of the residue.

 737 TYR   (  62-)  B      -7.22
1142 GLN   ( 478-)  B      -7.02
1302 LEU   ( 638-)  B      -6.95
1173 ARG   ( 509-)  B      -6.81
 492 ARG   ( 509-)  A      -6.78
1328 ARG   ( 664-)  B      -6.76
 621 LEU   ( 638-)  A      -6.74
 647 ARG   ( 664-)  A      -6.69
1271 ARG   ( 607-)  B      -6.65
 794 GLN   ( 119-)  B      -6.49
 590 ARG   ( 607-)  A      -6.48
 169 ARG   ( 169-)  A      -6.17
 844 ARG   ( 169-)  B      -6.14
 200 ARG   ( 200-)  A      -5.74
 875 ARG   ( 200-)  B      -5.71
 119 GLN   ( 119-)  A      -5.59
 460 LYS   ( 460-)  A      -5.58
1058 PHE   ( 383-)  B      -5.38
 702 GLN   (  27-)  B      -5.34
 210 ASN   ( 210-)  A      -5.19
 885 ASN   ( 210-)  B      -5.17
 375 ARG   ( 375-)  A      -5.14
 383 PHE   ( 383-)  A      -5.12
 361 GLN   ( 361-)  A      -5.10
1050 ARG   ( 375-)  B      -5.08
1036 GLN   ( 361-)  B      -5.06

Warning: Abnormal packing environment for sequential residues

A stretch of at least three sequential residues with a questionable packing environment was found. This could indicate that these residues are part of a strange loop. It might also be an indication of misthreading in the density. However, it can also indicate that one or more residues in this stretch have other problems such as, for example, missing atoms, very weird angles or bond lengths, etc.

The table below lists the first and last residue in each stretch found, as well as the average residue score of the series.

1140 GLU   ( 476-)  B      1142 - GLN    478- ( B)         -5.26

Note: Quality value plot

The quality value smoothed over a 10 residue window is plotted as function of the residue number. Low areas in the plot (below -2.0) indicate unusual packing.

Chain identifier: A

Note: Quality value plot

The quality value smoothed over a 10 residue window is plotted as function of the residue number. Low areas in the plot (below -2.0) indicate unusual packing.

Chain identifier: B

Warning: Low packing Z-score for some residues

The residues listed in the table below have an unusual packing environment according to the 2nd generation packing check. The score listed in the table is a packing normality Z-score: positive means better than average, negative means worse than average. Only residues scoring less than -2.50 are listed here. These are the unusual residues in the structure, so it will be interesting to take a special look at them.

1270 VAL   ( 606-)  B   -3.04
 589 VAL   ( 606-)  A   -3.00
1091 HIS   ( 416-)  B   -2.81

Note: Second generation quality Z-score plot

The second generation quality Z-score smoothed over a 10 residue window is plotted as function of the residue number. Low areas in the plot (below -1.3) indicate unusual packing.

Chain identifier: A

Note: Second generation quality Z-score plot

Chain identifier: B

Water, ion, and hydrogenbond related checks

Warning: Water molecules need moving

The water molecules listed in the table below were found to be significantly closer to a symmetry related non-water molecule than to the ones given in the coordinate file. For optimal viewing convenience revised coordinates for these water molecules should be given.

The number in brackets is the identifier of the water molecule in the input file. Suggested coordinates are also given in the table. Please note that alternative conformations for protein residues are not taken into account for this calculation. If you are using WHAT IF / WHAT-CHECK interactively, then the moved waters can be found in PDB format in the file: MOVEDH2O.pdb.

1366 HOH   ( 956 )  B      O    -15.08    9.49  -22.12
1366 HOH   (1051 )  B      O    -28.00  -37.45  -27.58
1366 HOH   (1138 )  B      O    -29.69    5.53   74.73

Error: Water molecules without hydrogen bonds

The water molecules listed in the table below do not form any hydrogen bonds, neither with the protein or DNA/RNA, nor with other water molecules. This is a strong indication of a refinement problem. The last number on each line is the identifier of the water molecule in the input file.

1365 HOH   (1012 )  A      O
Marked this atom as acceptor 1360  CL  ( 701-) A     CL
Marked this atom as acceptor 1363  CL  ( 704-) B     CL

Error: HIS, ASN, GLN side chain flips

Listed here are Histidine, Asparagine or Glutamine residues for which the orientation determined from hydrogen bonding analysis are different from the assignment given in the input. Either they could form energetically more favourable hydrogen bonds if the terminal group was rotated by 180 degrees, or there is no assignment in the input file (atom type 'A') but an assignment could be made. Be aware, though, that if the topology could not be determined for one or more ligands, then this option will make errors.

  20 HIS   (  20-)  A
  50 ASN   (  50-)  A
 115 GLN   ( 115-)  A
 135 ASN   ( 135-)  A
 139 ASN   ( 139-)  A
 210 ASN   ( 210-)  A
 226 ASN   ( 226-)  A
 235 ASN   ( 235-)  A
 393 ASN   ( 393-)  A
 447 GLN   ( 447-)  A
 509 ASN   ( 526-)  A
 533 HIS   ( 550-)  A
 541 GLN   ( 558-)  A
 550 ASN   ( 567-)  A
 695 HIS   (  20-)  B
 790 GLN   ( 115-)  B
 810 ASN   ( 135-)  B
 814 ASN   ( 139-)  B
 872 ASN   ( 197-)  B
 885 ASN   ( 210-)  B
 910 ASN   ( 235-)  B
 955 ASN   ( 280-)  B
1068 ASN   ( 393-)  B
1122 GLN   ( 447-)  B
1128 GLN   ( 453-)  B
1190 ASN   ( 526-)  B

Warning: Buried unsatisfied hydrogen bond donors

The buried hydrogen bond donors listed in the table below have a hydrogen atom that is not involved in a hydrogen bond in the optimized hydrogen bond network.

Hydrogen bond donors that are buried inside the protein normally use all of their hydrogens to form hydrogen bonds within the protein. If there are any non hydrogen bonded buried hydrogen bond donors in the structure they will be listed here. In very good structures the number of listed atoms will tend to zero.

Waters are not listed by this option.

 203 ALA   ( 203-)  A      N
 224 ASN   ( 224-)  A      N
 229 ASN   ( 229-)  A      ND2
 255 ILE   ( 255-)  A      N
 271 GLN   ( 271-)  A      N
 273 TRP   ( 273-)  A      N
 280 ASN   ( 280-)  A      ND2
 304 ARG   ( 304-)  A      N
 305 ASN   ( 305-)  A      ND2
 307 SER   ( 307-)  A      N
 329 PHE   ( 329-)  A      N
 333 ASN   ( 333-)  A      ND2
 482 ASN   ( 499-)  A      N
 544 ARG   ( 561-)  A      N
 573 ILE   ( 590-)  A      N
 585 ASN   ( 602-)  A      N
 605 GLU   ( 622-)  A      N
 636 ARG   ( 653-)  A      NH2
 677 ALA   (   2-)  B      N
 683 ILE   (   8-)  B      N
 686 GLN   (  11-)  B      NE2
 705 ILE   (  30-)  B      N
 710 GLN   (  35-)  B      N
 720 LYS   (  45-)  B      N
 741 SER   (  66-)  B      N
 759 SER   (  84-)  B      OG
 904 ASN   ( 229-)  B      ND2
 930 ILE   ( 255-)  B      N
 946 GLN   ( 271-)  B      N
 948 TRP   ( 273-)  B      N
 955 ASN   ( 280-)  B      ND2
 977 THR   ( 302-)  B      N
 979 ARG   ( 304-)  B      NH2
 984 ASP   ( 309-)  B      N
1004 PHE   ( 329-)  B      N
1055 GLN   ( 380-)  B      N
1145 SER   ( 481-)  B      OG
1146 ILE   ( 482-)  B      N
1172 SER   ( 508-)  B      OG
1175 THR   ( 511-)  B      N
1201 SER   ( 537-)  B      N
1254 ILE   ( 590-)  B      N
1266 ASN   ( 602-)  B      N
1286 GLU   ( 622-)  B      N
1342 LYS   ( 678-)  B      N

Warning: Buried unsatisfied hydrogen bond acceptors

The buried side-chain hydrogen bond acceptors listed in the table below are not involved in a hydrogen bond in the optimized hydrogen bond network.

Side-chain hydrogen bond acceptors buried inside the protein normally form hydrogen bonds within the protein. If there are any not hydrogen bonded in the optimized hydrogen bond network they will be listed here.

Waters are not listed by this option.

 280 ASN   ( 280-)  A      OD1
 295 ASN   ( 295-)  A      OD1
 330 HIS   ( 330-)  A      ND1
 970 ASN   ( 295-)  B      OD1
1250 GLU   ( 586-)  B      OE2

Warning: Unusual ion packing

We implemented the ion valence determination method of Brown and Wu [REF] similar to Nayal and Di Cera [REF]. See also Mueller, Koepke and Sheldrick [REF]. It must be stated that the validation of ions in PDB files is very difficult. Ideal ion-ligand distances often differ no more than 0.1 Angstrom, and in a 2.0 Angstrom resolution structure 0.1 Angstrom is not very much. Nayal and Di Cera showed that this method has great potential, but the method has not been validated. Part of our implementation (comparing ion types) is even fully new and despite that we see it work well in the few cases that are trivial, we must emphasize that this validation method is untested. See: swift.cmbi.ru.nl/teach/theory/ for a detailed explanation.

The output gives the ion, the valency score for the ion itself, the valency score for the suggested alternative ion, and a series of possible comments *1 indicates that the suggested alternate atom type has been observed in the PDB file at another location in space. *2 indicates that WHAT IF thinks to have found this ion type in the crystallisation conditions as described in the REMARK 280 cards of the PDB file. *S Indicates that this ions is located at a special position (i.e. at a symmetry axis). N4 stands for NH4+.

1361  CA   ( 702-)  A     0.63   0.84 Scores about as good as NA
1364  CA   ( 705-)  B     0.80   1.04 Scores about as good as NA

Warning: Unusual water packing

We implemented the ion valence determination method of Brown and Wu [REF] similar to Nayal and Di Cera [REF] and Mueller, Koepke and Sheldrick [REF]. It must be stated that the validation of ions in PDB files is very difficult. Ideal ion-ligand distances often differ no more than 0.1 Angstrom, and in a 2.0 Angstrom resolution structure 0.1 Angstrom is not very much. Nayal and Di Cera showed that this method nevertheless has great potential for detecting water molecules that actually should be metal ions. The method has not been extensively validated, though. Part of our implementation (comparing waters with multiple ion types) is even fully new and despite that we see it work well in the few cases that are trivial, we must emphasize that this method is untested.

The score listed is the valency score. This number should be close to (preferably a bit above) 1.0 for the suggested ion to be a likely alternative for the water molecule. Ions listed in brackets are good alternate choices. *1 indicates that the suggested ion-type has been observed elsewhere in the PDB file too. *2 indicates that the suggested ion-type has been observed in the REMARK 280 cards of the PDB file. Ion-B and ION-B indicate that the B-factor of this water is high, or very high, respectively. H2O-B indicates that the B-factors of atoms that surround this water/ion are suspicious. See: swift.cmbi.ru.nl/teach/theory/ for a detailed explanation.

1365 HOH   ( 757 )  A      O  1.13  K  4
1365 HOH   ( 823 )  A      O  1.02  K  5
1365 HOH   ( 880 )  A      O  0.89  K  5 Ion-B
1365 HOH   ( 974 )  A      O  0.98 NA  4 Ion-B
1366 HOH   ( 742 )  B      O  1.11  K  4 NCS 1/1
1366 HOH   ( 915 )  B      O  0.97  K  4 Ion-B NCS 1/1

Warning: Possible wrong residue type

The residues listed in the table below have a weird environment that cannot be improved by rotamer flips. This can mean one of three things, non of which WHAT CHECK really can do much about. 1) The side chain has actually another rotamer than is present in the PDB file; 2) A counter ion is present in the structure but is not given in the PDB file; 3) The residue actually is another amino acid type. The annotation 'Alt-rotamer' indicates that WHAT CHECK thinks you might want to find an alternate rotamer for this residue. The annotation 'Sym-induced' indicates that WHAT CHECK believes that symmetry contacts might have something to do with the difficulties of this residue's side chain. Determination of these two annotations is difficult, so their absence is less meaningful than their presence. The annotation Ligand-bound indicates that a ligand seems involved with this residue. In nine of ten of these cases this indicates that the ligand is causing the weird situation rather than the residue.

 181 GLU   ( 181-)  A   H-bonding suggests Gln; but Alt-Rotamer
 493 ASP   ( 510-)  A   H-bonding suggests Asn; but Alt-Rotamer
1174 ASP   ( 510-)  B   H-bonding suggests Asn; but Alt-Rotamer
1244 GLU   ( 580-)  B   H-bonding suggests Gln; but Alt-Rotamer
1263 GLU   ( 599-)  B   H-bonding suggests Gln; but Alt-Rotamer

Final summary

Note: Summary report for users of a structure

This is an overall summary of the quality of the structure as compared with current reliable structures. This summary is most useful for biologists seeking a good structure to use for modelling calculations.

The second part of the table mostly gives an impression of how well the model conforms to common refinement restraint values. The first part of the table shows a number of global quality indicators.


Structure Z-scores, positive is better than average:

  1st generation packing quality :   0.000
  2nd generation packing quality :  -1.707
  Ramachandran plot appearance   :  -1.127
  chi-1/chi-2 rotamer normality  :  -1.387
  Backbone conformation          :   0.160

RMS Z-scores, should be close to 1.0:
  Bond lengths                   :   0.267 (tight)
  Bond angles                    :   0.575 (tight)
  Omega angle restraints         :   0.234 (tight)
  Side chain planarity           :   0.257 (tight)
  Improper dihedral distribution :   0.571
  B-factor distribution          :   0.407
  Inside/Outside distribution    :   0.994

Note: Summary report for depositors of a structure

This is an overall summary of the quality of the X-ray structure as compared with structures solved at similar resolutions. This summary can be useful for a crystallographer to see if the structure makes the best possible use of the data. Warning. This table works well for structures solved in the resolution range of the structures in the WHAT IF database, which is presently (summer 2008) mainly 1.1 - 1.3 Angstrom. The further the resolution of your file deviates from this range the more meaningless this table becomes.

The second part of the table mostly gives an impression of how well the model conforms to common refinement restraint values. The first part of the table shows a number of global quality indicators, which have been calibrated against structures of similar resolution.

Resolution found in PDB file : 2.10


Structure Z-scores, positive is better than average:

  1st generation packing quality :   0.4
  2nd generation packing quality :  -1.1
  Ramachandran plot appearance   :  -0.3
  chi-1/chi-2 rotamer normality  :  -0.3
  Backbone conformation          :   0.2

RMS Z-scores, should be close to 1.0:
  Bond lengths                   :   0.267 (tight)
  Bond angles                    :   0.575 (tight)
  Omega angle restraints         :   0.234 (tight)
  Side chain planarity           :   0.257 (tight)
  Improper dihedral distribution :   0.571
  B-factor distribution          :   0.407
  Inside/Outside distribution    :   0.994
==============

WHAT IF
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      WHAT IF: a molecular modelling and drug design program,
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WHAT_CHECK (verification routines from WHAT IF)
    R.W.W.Hooft, G.Vriend, C.Sander and E.E.Abola,
      Errors in protein structures
    Nature 381, 272 (1996).
    (see also http://swift.cmbi.ru.nl/gv/whatcheck for a course and extra inform

Bond lengths and angles, protein residues
    R.Engh and R.Huber,
      Accurate bond and angle parameters for X-ray protein structure
      refinement,
    Acta Crystallogr. A47, 392--400 (1991).

Bond lengths and angles, DNA/RNA
    G.Parkinson, J.Voitechovsky, L.Clowney, A.T.Bruenger and H.Berman,
      New parameters for the refinement of nucleic acid-containing structures
    Acta Crystallogr. D52, 57--64 (1996).

DSSP
    W.Kabsch and C.Sander,
      Dictionary of protein secondary structure: pattern
      recognition of hydrogen bond and geometrical features
    Biopolymers 22, 2577--2637 (1983).

Hydrogen bond networks
    R.W.W.Hooft, C.Sander and G.Vriend,
      Positioning hydrogen atoms by optimizing hydrogen bond networks in
      protein structures
    PROTEINS, 26, 363--376 (1996).

Matthews' Coefficient
    B.W.Matthews
      Solvent content of Protein Crystals
    J. Mol. Biol. 33, 491--497 (1968).

Protein side chain planarity
    R.W.W. Hooft, C. Sander and G. Vriend,
      Verification of protein structures: side-chain planarity
    J. Appl. Cryst. 29, 714--716 (1996).

Puckering parameters
    D.Cremer and J.A.Pople,
      A general definition of ring puckering coordinates
    J. Am. Chem. Soc. 97, 1354--1358 (1975).

Quality Control
    G.Vriend and C.Sander,
      Quality control of protein models: directional atomic
      contact analysis,
    J. Appl. Cryst. 26, 47--60 (1993).

Ramachandran plot
    G.N.Ramachandran, C.Ramakrishnan and V.Sasisekharan,
      Stereochemistry of Polypeptide Chain Conformations
    J. Mol. Biol. 7, 95--99 (1963).

Symmetry Checks
    R.W.W.Hooft, C.Sander and G.Vriend,
      Reconstruction of symmetry related molecules from protein
      data bank (PDB) files
    J. Appl. Cryst. 27, 1006--1009 (1994).

Ion Checks
    I.D.Brown and K.K.Wu,
      Empirical Parameters for Calculating Cation-Oxygen Bond Valences
    Acta Cryst. B32, 1957--1959 (1975).

    M.Nayal and E.Di Cera,
      Valence Screening of Water in Protein Crystals Reveals Potential Na+
      Binding Sites
    J.Mol.Biol. 256 228--234 (1996).

    P.Mueller, S.Koepke and G.M.Sheldrick,
      Is the bond-valence method able to identify metal atoms in protein
      structures?
    Acta Cryst. D 59 32--37 (2003).

Checking checks
    K.Wilson, C.Sander, R.W.W.Hooft, G.Vriend, et al.
      Who checks the checkers
    J.Mol.Biol. (1998) 276,417-436.