WHAT IF Check report

This file was created 2011-12-13 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 pdb3b7e.ent

Checks that need to be done early-on in validation

Note: Non crystallographic symmetry RMS plot

The plot shows the RMS differences between two similar chains on a residue- by-residue basis. Individual "spikes" can be indicative of interesting or wrong residues. If all residues show a high RMS value, the structure could be incorrectly refined.

Chain identifiers of the two chains: A and B

All-atom RMS fit for the two chains : 0.300
CA-only RMS fit for the two chains : 0.104

Warning: Ligands for which a topology was generated automatically

The topology for the ligands in the table below were determined automatically. WHAT IF uses a local copy of Daan van Aalten's Dundee PRODRG server to automatically generate topology information for ligands. For this PDB file that seems to have gone fine, but be aware that automatic topology generation is a complicated task. So, if you get messages that you fail to understand or that you believe are wrong, and one of these ligands is involved, then check the ligand topology first.

 779 ZMR   (1001-)  A  -
 791 ZMR   (1002-)  B  -

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. The header of the PDB file states that TLS groups were used. So, if WHAT IF complains about your B-factors, while 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:


Number of TLS groups mentione in PDB file header: 0

Crystal temperature (K) :100.000

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: Tyrosine convention problem

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

 126 TYR   ( 207-)  A
 171 TYR   ( 252-)  A
 511 TYR   ( 207-)  B
 585 TYR   ( 281-)  B

Warning: Phenylalanine convention problem

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

  33 PHE   ( 115-)  A
  39 PHE   ( 121-)  A
 224 PHE   ( 305-)  A
 240 PHE   ( 322-)  A
 269 PHE   ( 354-)  A
 340 PHE   ( 422-)  A
 418 PHE   ( 115-)  B
 424 PHE   ( 121-)  B
 625 PHE   ( 322-)  B
 654 PHE   ( 354-)  B
 725 PHE   ( 422-)  B

Geometric checks

Warning: Low bond length variability

Bond lengths were found to deviate less than normal from the mean Engh and Huber [REF] and/or Parkinson et al [REF] standard bond lengths. The RMS Z-score given below is expected to be near 1.0 for a normally restrained data set. The fact that it is lower than 0.667 in this structure might indicate that too-strong restraints have been used in the refinement. This can only be a problem for high resolution X-ray structures.

RMS Z-score for bond lengths: 0.539
RMS-deviation in bond distances: 0.014

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

 |  0.997376  0.000459 -0.000022|
 |  0.000459  0.999781 -0.000283|
 | -0.000022 -0.000283  0.996740|
Proposed new scale matrix

 |  0.008493 -0.000004  0.000000|
 | -0.000004  0.007739  0.000002|
 |  0.000000  0.000002  0.008442|
With corresponding cell

    A    = 117.740  B   = 129.221  C    = 118.462
    Alpha=  90.033  Beta=  90.001  Gamma=  89.947

The CRYST1 cell dimensions

    A    = 118.044  B   = 129.247  C    = 118.845
    Alpha=  90.000  Beta=  90.000  Gamma=  90.000

Variance: 123.434
(Under-)estimated Z-score: 8.188

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.

   2 ILE   (  84-)  A      N    CA   CB  118.62    4.8
 387 ILE   (  84-)  B      N    CA   CB  117.56    4.2
 712 HIS   ( 412-)  B      CG   ND1  CE1 109.63    4.0

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.

 588 THR   ( 284-)  B    -3.3
 203 THR   ( 284-)  A    -3.3
 734 PRO   ( 431-)  B    -2.6
 373 TRP   ( 456-)  A    -2.4
 758 TRP   ( 456-)  B    -2.4
 529 THR   ( 225-)  B    -2.4
 144 THR   ( 225-)  A    -2.4
  36 ARG   ( 118-)  A    -2.4
 600 HIS   ( 296-)  B    -2.3
 215 HIS   ( 296-)  A    -2.3
 421 ARG   ( 118-)  B    -2.3
 473 TYR   ( 169-)  B    -2.3
 543 THR   ( 239-)  B    -2.2
 349 PRO   ( 431-)  A    -2.2
  88 TYR   ( 169-)  A    -2.2
 158 THR   ( 239-)  A    -2.1
 497 GLY   ( 193-)  B    -2.0
 112 GLY   ( 193-)  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.

  33 PHE   ( 115-)  A  omega poor
  35 ILE   ( 117-)  A  omega poor
  59 ASN   ( 141-)  A  Poor phi/psi
  66 THR   ( 148-)  A  omega poor
  96 ALA   ( 177-)  A  omega poor
 108 TRP   ( 189-)  A  omega poor
 127 ASN   ( 208-)  A  Poor phi/psi
 139 ASN   ( 220-)  A  Poor phi/psi
 141 ILE   ( 222-)  A  Poor phi/psi
 144 THR   ( 225-)  A  Poor phi/psi, omega poor
 145 GLN   ( 226-)  A  omega poor
 146 GLU   ( 227-)  A  Poor phi/psi
 153 ASN   ( 234-)  A  Poor phi/psi
 191 ASN   ( 272-)  A  Poor phi/psi
 209 VAL   ( 290-)  A  omega poor
 217 SER   ( 298-)  A  omega poor
 228 LEU   ( 310-)  A  Poor phi/psi, omega poor
 243 ASN   ( 325-)  A  PRO omega poor
 253 CYS   ( 336-)  A  omega poor
 259 ASN   ( 344-)  A  Poor phi/psi
 262 ASN   ( 347-)  A  Poor phi/psi
 272 ASP   ( 357-)  A  Poor phi/psi
 275 VAL   ( 360-)  A  omega poor
 318 SER   ( 404-)  A  Poor phi/psi
 323 SER   ( 409-)  A  omega poor
And so on for a total of 61 lines.

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!

   4 THR   (  86-)  A      0
   6 ASN   (  88-)  A      0
  19 SER   ( 101-)  A      0
  28 SER   ( 110-)  A      0
  29 LYS   ( 111-)  A      0
  33 PHE   ( 115-)  A      0
  35 ILE   ( 117-)  A      0
  37 GLU   ( 119-)  A      0
  38 PRO   ( 120-)  A      0
  44 HIS   ( 126-)  A      0
  45 LEU   ( 127-)  A      0
  46 GLU   ( 128-)  A      0
  54 GLN   ( 136-)  A      0
  58 LEU   ( 140-)  A      0
  59 ASN   ( 141-)  A      0
  64 ASN   ( 146-)  A      0
  66 THR   ( 148-)  A      0
  67 VAL   ( 149-)  A      0
  70 ARG   ( 152-)  A      0
  74 ARG   ( 156-)  A      0
  81 VAL   ( 163-)  A      0
  86 SER   ( 168-)  A      0
  93 GLU   ( 174-)  A      0
  94 SER   ( 175-)  A      0
  95 VAL   ( 176-)  A      0
And so on for a total of 427 lines.

Warning: Omega angle restraints not strong enough

The omega angles for trans-peptide bonds in a structure is expected to give a gaussian distribution with the average around +178 degrees, and a standard deviation around 5.5. In the current structure the standard deviation of this distribution is above 7.0, which indicates that the omega values have been under-restrained.

Standard deviation of omega values : 7.149

Warning: Unusual PRO puckering amplitudes

The proline residues listed in the table below have a puckering amplitude that is outside of normal ranges. Puckering parameters were calculated by the method of Cremer and Pople [REF]. Normal PRO rings have a puckering amplitude Q between 0.20 and 0.45 Angstrom. If Q is lower than 0.20 Angstrom for a PRO residue, this could indicate disorder between the two different normal ring forms (with C-gamma below and above the ring, respectively). If Q is higher than 0.45 Angstrom something could have gone wrong during the refinement. Be aware that this is a warning with a low confidence level. See: Who checks the checkers? Four validation tools applied to eight atomic resolution structures [REF]

  72 PRO   ( 154-)  A    0.14 LOW
 246 PRO   ( 328-)  A    0.15 LOW
 457 PRO   ( 154-)  B    0.17 LOW

Warning: Unusual PRO puckering phases

The proline residues listed in the table below have a puckering phase that is not expected to occur in protein structures. Puckering parameters were calculated by the method of Cremer and Pople [REF]. Normal PRO rings approximately show a so-called envelope conformation with the C-gamma atom above the plane of the ring (phi=+72 degrees), or a half-chair conformation with C-gamma below and C-beta above the plane of the ring (phi=-90 degrees). If phi deviates strongly from these values, this is indicative of a very strange conformation for a PRO residue, and definitely requires a manual check of the data. Be aware that this is a warning with a low confidence level. See: Who checks the checkers? Four validation tools applied to eight atomic resolution structures [REF].

  87 PRO   ( 169-)  A  -112.9 envelop C-gamma (-108 degrees)
 472 PRO   ( 169-)  B  -112.3 envelop C-gamma (-108 degrees)
 734 PRO   ( 431-)  B   -59.5 half-chair C-beta/C-alpha (-54 degrees)

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.

 153 ASN   ( 234-)  A      ND2 <->  792 HOH   (1356 )  A      O      0.34    2.36  INTRA
 523 ARG   ( 219-)  B      NH1 <->  793 HOH   (1272 )  B      O      0.27    2.43  INTRA
 386 VAL   (  83-)  B      CG1 <->  793 HOH   (1340 )  B      O      0.25    2.55  INTRA
 253 CYS   ( 336-)  A      CB  <->  792 HOH   (1183 )  A      O      0.24    2.56  INTRA
 538 ASN   ( 234-)  B      ND2 <->  793 HOH   (1342 )  B      O      0.21    2.49  INTRA
  62 HIS   ( 144-)  A      NE2 <->  765 GLU   ( 463-)  B      N      0.17    2.83  INTRA BL
 377 ASP   ( 460-)  A      O   <->  792 HOH   (1472 )  A      O      0.13    2.27  INTRA
 101 ALA   ( 182-)  A      C   <->  149 CYS   ( 230-)  A      SG     0.12    3.28  INTRA BL
 271 TYR   ( 356-)  A      CD2 <->  780 GOL   (1007-)  A      C3     0.11    3.09  INTRA
 563 LYS   ( 259-)  B      O   <->  565 LYS   ( 261-)  B      NZ     0.11    2.59  INTRA
 705 TYR   ( 406-)  B      OH  <->  791 ZMR   (1002-)  B      C2     0.09    2.71  INTRA
 272 ASP   ( 357-)  A      OD1 <->  792 HOH   (1304 )  A      O      0.08    2.32  INTRA
 647 ASN   ( 347-)  B    A OD1 <->  793 HOH   (1174 )  B      O      0.08    2.32  INTRA BL
 486 ALA   ( 182-)  B      C   <->  534 CYS   ( 230-)  B      SG     0.08    3.32  INTRA BL
 612 ASN   ( 309-)  B      CB  <->  793 HOH   (1278 )  B      O      0.08    2.72  INTRA
 386 VAL   (  83-)  B      CG2 <->  793 HOH   (1459 )  B      O      0.07    2.73  INTRA BF
 488 HIS   ( 184-)  B      ND1 <->  490 GLY   ( 186-)  B      N      0.07    2.93  INTRA BL
 762 ASP   ( 460-)  B      O   <->  793 HOH   (1269 )  B      O      0.07    2.33  INTRA
  20 LYS   ( 102-)  A      NZ  <->  376 PRO   ( 459-)  A      O      0.06    2.64  INTRA
 103 HIS   ( 184-)  A      ND1 <->  105 GLY   ( 186-)  A      N      0.06    2.94  INTRA BL
 422 GLU   ( 119-)  B      N   <->  423 PRO   ( 120-)  B      CD     0.05    2.95  INTRA BL
  91 ARG   ( 172-)  A      NE  <->   93 GLU   ( 174-)  A      OE2    0.05    2.65  INTRA
 638 CYS   ( 336-)  B      CB  <->  793 HOH   (1234 )  B      O      0.05    2.75  INTRA
 320 TYR   ( 406-)  A      OH  <->  779 ZMR   (1001-)  A      C2     0.04    2.76  INTRA BL
  37 GLU   ( 119-)  A      N   <->   38 PRO   ( 120-)  A      CD     0.04    2.96  INTRA BL
 476 ARG   ( 172-)  B      NE  <->  478 GLU   ( 174-)  B      OE2    0.04    2.66  INTRA
 594 VAL   ( 290-)  B      C   <->  595 CYS   ( 291-)  B      SG     0.04    3.26  INTRA BL
 786 GOL   (1000-)  B      C3  <->  793 HOH   (1273 )  B      O      0.04    2.76  INTRA
 153 ASN   ( 234-)  A      ND2 <->  792 HOH   (1402 )  A      O      0.03    2.67  INTRA
 504 GLY   ( 200-)  B      O   <->  520 LYS   ( 216-)  B      NZ     0.03    2.67  INTRA
   1 VAL   (  83-)  A      O   <->  105 GLY   ( 186-)  A      C      0.03    2.77  INTRA
 189 ALA   ( 270-)  A      N   <->  190 PRO   ( 271-)  A      CD     0.03    2.97  INTRA BL
 574 ALA   ( 270-)  B      N   <->  575 PRO   ( 271-)  B      CD     0.02    2.98  INTRA BL
 557 LYS   ( 253-)  B      NZ  <->  790 GOL   (1008-)  B      O3     0.02    2.68  INTRA
 102 CYS   ( 183-)  A      SG  <->  151 CYS   ( 232-)  A      SG     0.01    3.44  INTRA BL
 327 HIS   ( 412-)  A      ND1 <->  792 HOH   (1050 )  A      O      0.01    2.69  INTRA BL
  83 GLU   ( 165-)  A      OE1 <->  785 GOL   (1010-)  A      C1     0.01    2.79  INTRA
 209 VAL   ( 290-)  A      C   <->  210 CYS   ( 291-)  A      SG     0.01    3.29  INTRA BL

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.

 458 TYR   ( 155-)  B      -6.19
 430 LEU   ( 127-)  B      -5.88
  45 LEU   ( 127-)  A      -5.81
 491 MET   ( 187-)  B      -5.47
 106 MET   ( 187-)  A      -5.46
 473 TYR   ( 169-)  B      -5.38
 455 ARG   ( 152-)  B      -5.24
  70 ARG   ( 152-)  A      -5.22
 247 ASN   ( 329-)  A      -5.20
 632 ASN   ( 329-)  B      -5.18
 553 GLN   ( 249-)  B      -5.16
 168 GLN   ( 249-)  A      -5.09
  73 TYR   ( 155-)  A      -5.03

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.

 735 LYS   ( 432-)  B   -2.74
 309 GLN   ( 395-)  A   -2.59
 694 GLN   ( 395-)  B   -2.58

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.

 792 HOH   (1331 )  A      O     18.58   38.26  -13.30

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.

   6 ASN   (  88-)  A

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.

  15 TRP   (  97-)  A      NE1
  20 LYS   ( 102-)  A      N
  36 ARG   ( 118-)  A      NH2
  40 ILE   ( 122-)  A      N
  56 ALA   ( 138-)  A      N
  59 ASN   ( 141-)  A      N
  60 ASP   ( 142-)  A      N
  71 SER   ( 153-)  A      N
 147 SER   ( 228-)  A      N
 167 GLY   ( 248-)  A      N
 194 TYR   ( 275-)  A      N
 265 LYS   ( 350-)  A      N
 335 CYS   ( 417-)  A      N
 355 TRP   ( 438-)  A      N
 368 SER   ( 451-)  A      N
 400 TRP   (  97-)  B      NE1
 405 LYS   ( 102-)  B      N
 421 ARG   ( 118-)  B      NH2
 425 ILE   ( 122-)  B      N
 441 ALA   ( 138-)  B      N
 456 SER   ( 153-)  B      N
 532 SER   ( 228-)  B      N
 552 GLY   ( 248-)  B      N
 579 TYR   ( 275-)  B      N
 648 GLY   ( 348-)  B      N
 650 LYS   ( 350-)  B      N
 720 CYS   ( 417-)  B      N
 740 TRP   ( 438-)  B      N
 747 SER   ( 445-)  B      OG
 753 SER   ( 451-)  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.

 195 GLU   ( 276-)  A      OE1
 580 GLU   ( 276-)  B      OE1

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+.

 776  CA   (   1-)  A     0.89   1.13 Scores about as good as NA
 778  CA   (1006-)  A     0.52   0.71 Scores about as good as NA *S
 783  CA   (   1-)  B     0.86   1.11 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.

 792 HOH   (1199 )  A      O  1.07  K  4
 792 HOH   (1325 )  A      O  1.14  K  4 Ion-B
 792 HOH   (1327 )  A      O  0.91  K  5 Ion-B
 792 HOH   (1433 )  A      O  0.96  K  5 Ion-B
 792 HOH   (1445 )  A      O  0.94  K  4 ION-B
 793 HOH   (1078 )  B      O  1.15  K  4 NCS 1/1
 793 HOH   (1168 )  B      O  0.92  K  5 NCS 1/1
 793 HOH   (1193 )  B      O  0.90  K  6 NCS 1/1
 793 HOH   (1266 )  B      O  0.87  K  4 Ion-B NCS 1/1
 793 HOH   (1348 )  B      O  0.99  K  4 Ion-B NCS 1/1
 793 HOH   (1403 )  B      O  0.87  K  4 Ion-B

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.

 104 ASP   ( 185-)  A   H-bonding suggests Asn; but Alt-Rotamer
 162 ASP   ( 243-)  A   H-bonding suggests Asn
 468 GLU   ( 165-)  B   H-bonding suggests Gln; but Alt-Rotamer; Ligand-contact
 489 ASP   ( 185-)  B   H-bonding suggests Asn; but Alt-Rotamer
 547 ASP   ( 243-)  B   H-bonding suggests Asn

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 :  -0.423
  2nd generation packing quality :  -1.985
  Ramachandran plot appearance   :  -0.561
  chi-1/chi-2 rotamer normality  :  -0.822
  Backbone conformation          :  -0.967

RMS Z-scores, should be close to 1.0:
  Bond lengths                   :   0.539 (tight)
  Bond angles                    :   0.706
  Omega angle restraints         :   1.300 (loose)
  Side chain planarity           :   0.829
  Improper dihedral distribution :   0.815
  B-factor distribution          :   0.666
  Inside/Outside distribution    :   1.053

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 : 1.45


Structure Z-scores, positive is better than average:

  1st generation packing quality :  -0.1
  2nd generation packing quality :  -1.7
  Ramachandran plot appearance   :  -1.0
  chi-1/chi-2 rotamer normality  :  -1.3
  Backbone conformation          :  -1.5

RMS Z-scores, should be close to 1.0:
  Bond lengths                   :   0.539 (tight)
  Bond angles                    :   0.706
  Omega angle restraints         :   1.300 (loose)
  Side chain planarity           :   0.829
  Improper dihedral distribution :   0.815
  B-factor distribution          :   0.666
  Inside/Outside distribution    :   1.053
==============

WHAT IF
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WHAT_CHECK (verification routines from WHAT IF)
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    (see also http://swift.cmbi.ru.nl/gv/whatcheck for a course and extra inform

Bond lengths and angles, protein residues
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Bond lengths and angles, DNA/RNA
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DSSP
    W.Kabsch and C.Sander,
      Dictionary of protein secondary structure: pattern
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    Biopolymers 22, 2577--2637 (1983).

Hydrogen bond networks
    R.W.W.Hooft, C.Sander and G.Vriend,
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      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.