WHAT IF Check report

This file was created 2011-12-18 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 pdb1snt.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

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

Warning: Occupancies atoms do not add up to 1.0.

In principle, the occupancy of all alternates of one atom should add up till 1.0. A valid exception is the missing atom (i.e. an atom not seen in the electron density) that is allowed to have a 0.0 occupancy. Sometimes this even happens when there are no alternate atoms given...

Atoms want to move. That is the direct result of the second law of thermodynamics, in a somewhat weird way of thinking. Any way, many atoms seem to have more than one position where they like to sit, and they jump between them. The population difference between those sites (which is related to their energy differences) is seen in the occupancy factors. As also for atoms it is 'to be or not to be', these occupancies should add up to 1.0. Obviously, it is possible that they add up to a number less than 1.0, in cases where there are yet more, but undetected' rotamers/positions in play, but also in those cases a warning is in place as the information shown in the PDB file is less certain than it could have been. The residues listed below contain atoms that have an occupancy greater than zero, but all their alternates do not add up to one.

WARNING. Presently WHAT CHECK only deals with a maximum of two alternate positions. A small number of atoms in the PDB has three alternates. In those cases the warning given here should obviously be neglected! In a next release we will try to fix this.

  63 GLU   (  72-)  A    0.50
  69 ARG   (  78-)  A    0.50
  74 ARG   (  83-)  A    0.50
  81 LEU   (  90-)  A    0.67
 131 ARG   ( 152-)  A    0.50
 300 VAL   ( 325-)  A    1.34
 332 ASN   ( 357-)  A    0.50

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:

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

Nomenclature related problems

Warning: Valine nomenclature problem

The valine residues listed in the table below have their C-gamma-1 and C-gamma-2 swapped.

 300 VAL   ( 325-)  A

Warning: Leucine nomenclature problem

The leucine residues listed in the table below have their C-delta-1 and C-delta-2 swapped.

  81 LEU   (  90-)  A

Warning: Tyrosine convention problem

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

 158 TYR   ( 179-)  A
 270 TYR   ( 295-)  A
 329 TYR   ( 354-)  A

Warning: Phenylalanine convention problem

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

  35 PHE   (  37-)  A
  90 PHE   (  99-)  A
  93 PHE   ( 102-)  A
 136 PHE   ( 157-)  A
 174 PHE   ( 195-)  A
 258 PHE   ( 279-)  A

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.

 123 ASP   ( 144-)  A
 194 ASP   ( 215-)  A
 281 ASP   ( 306-)  A
 311 ASP   ( 336-)  A
 333 ASP   ( 358-)  A

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.

  41 GLU   (  50-)  A
  63 GLU   (  72-)  A
 132 GLU   ( 153-)  A
 245 GLU   ( 266-)  A
 294 GLU   ( 319-)  A
 298 GLU   ( 323-)  A
 336 GLU   ( 361-)  A

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: 0.272
RMS-deviation in bond distances: 0.006

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.

 197 GLU   ( 218-)  A     -C    N    CA  131.30    5.3

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.

  41 GLU   (  50-)  A
  63 GLU   (  72-)  A
 123 ASP   ( 144-)  A
 132 GLU   ( 153-)  A
 194 ASP   ( 215-)  A
 245 GLU   ( 266-)  A
 281 ASP   ( 306-)  A
 294 GLU   ( 319-)  A
 298 GLU   ( 323-)  A
 300 VAL   ( 325-)  A
 311 ASP   ( 336-)  A
 333 ASP   ( 358-)  A
 336 GLU   ( 361-)  A

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.

 144 LEU   ( 165-)  A    4.37
 125 ALA   ( 146-)  A    4.36
 215 ALA   ( 236-)  A    4.12
 176 PHE   ( 197-)  A    4.11

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.

 291 PRO   ( 316-)  A    -3.0
 166 ILE   ( 187-)  A    -2.9
 248 PRO   ( 269-)  A    -2.8
 135 THR   ( 156-)  A    -2.7
 122 THR   ( 143-)  A    -2.7
 164 HIS   ( 185-)  A    -2.4
  20 ILE   (  22-)  A    -2.4
  42 LEU   (  51-)  A    -2.3
 174 PHE   ( 195-)  A    -2.1
 196 LEU   ( 217-)  A    -2.1
  45 LEU   (  54-)  A    -2.1
  16 HIS   (  18-)  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.

  16 HIS   (  18-)  A  Poor phi/psi
  20 ILE   (  22-)  A  Poor phi/psi
  30 GLN   (  32-)  A  Poor phi/psi
  68 ALA   (  77-)  A  Poor phi/psi
  77 ASN   (  86-)  A  Poor phi/psi
 111 HIS   ( 132-)  A  Poor phi/psi
 139 GLY   ( 160-)  A  PRO omega poor
 151 ARG   ( 172-)  A  Poor phi/psi
 181 HIS   ( 202-)  A  Poor phi/psi
 191 VAL   ( 212-)  A  Poor phi/psi
 194 ASP   ( 215-)  A  Poor phi/psi
 196 LEU   ( 217-)  A  Poor phi/psi
 219 LEU   ( 240-)  A  Poor phi/psi
 230 ASP   ( 251-)  A  Poor phi/psi
 247 PRO   ( 268-)  A  PRO omega poor
 272 HIS   ( 297-)  A  Poor phi/psi
 281 ASP   ( 306-)  A  Poor phi/psi
 290 PRO   ( 315-)  A  PRO omega poor
 308 ALA   ( 333-)  A  Poor phi/psi
 334 TYR   ( 359-)  A  Poor phi/psi
 chi-1/chi-2 correlation Z-score : -1.402

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!

   6 GLN   (   8-)  A      0
  10 VAL   (  12-)  A      0
  13 SER   (  15-)  A      0
  17 ALA   (  19-)  A      0
  18 TYR   (  20-)  A      0
  19 ARG   (  21-)  A      0
  20 ILE   (  22-)  A      0
  21 PRO   (  23-)  A      0
  30 GLN   (  32-)  A      0
  38 GLN   (  40-)  A      0
  39 ARG   (  41-)  A      0
  40 ALA   (  49-)  A      0
  41 GLU   (  50-)  A      0
  54 THR   (  63-)  A      0
  55 HIS   (  64-)  A      0
  60 GLN   (  69-)  A      0
  66 ALA   (  75-)  A      0
  68 ALA   (  77-)  A      0
  69 ARG   (  78-)  A      0
  70 LEU   (  79-)  A      0
  71 ASP   (  80-)  A      0
  75 SER   (  84-)  A      0
  76 MET   (  85-)  A      0
  77 ASN   (  86-)  A      0
  78 PRO   (  87-)  A      0
And so on for a total of 171 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 : 1.670

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.

 163 LEU   ( 184-)  A      C   <->  165 PRO   ( 186-)  A      CD     0.32    2.88  INTRA BF
  81 LEU   (  90-)  A      CB  <->  143 CYS   ( 164-)  A    A SG     0.28    3.12  INTRA BL
 187 ARG   ( 208-)  A      NH1 <->  353 HOH   ( 709 )  A      O      0.18    2.52  INTRA BF
  39 ARG   (  41-)  A      NE  <->  353 HOH   ( 702 )  A      O      0.15    2.55  INTRA BF
 162 LYS   ( 183-)  A      C   <->  164 HIS   ( 185-)  A      N      0.15    2.75  INTRA BF
 197 GLU   ( 218-)  A      OE1 <->  216 ARG   ( 237-)  A      NH1    0.15    2.55  INTRA
 349 PRO   ( 374-)  A      O   <->  352 TYR   ( 377-)  A      N      0.14    2.56  INTRA BF
 164 HIS   ( 185-)  A      O   <->  166 ILE   ( 187-)  A      N      0.13    2.57  INTRA BF
  83 ASP   (  92-)  A      OD2 <->  181 HIS   ( 202-)  A      ND1    0.12    2.58  INTRA BL
 220 ARG   ( 241-)  A      NE  <->  353 HOH   ( 692 )  A      O      0.11    2.59  INTRA BF
 147 ASN   ( 168-)  A      O   <->  209 ARG   ( 230-)  A      NH1    0.10    2.60  INTRA BF
 164 HIS   ( 185-)  A      N   <->  165 PRO   ( 186-)  A      CD     0.10    2.90  INTRA BF
  83 ASP   (  92-)  A      O   <->   87 GLY   (  96-)  A      N      0.10    2.60  INTRA
 164 HIS   ( 185-)  A      C   <->  166 ILE   ( 187-)  A      N      0.10    2.80  INTRA BF
   1 SER   (   3-)  A      N   <->  353 HOH   ( 729 )  A      O      0.10    2.60  INTRA BF
  19 ARG   (  21-)  A      NE  <->  330 GLU   ( 355-)  A      OE2    0.09    2.61  INTRA
 209 ARG   ( 230-)  A      NH2 <->  353 HOH   ( 697 )  A      O      0.08    2.62  INTRA BF
 206 GLY   ( 227-)  A      N   <->  353 HOH   ( 679 )  A      O      0.08    2.62  INTRA BF
  51 ASP   (  60-)  A      O   <->   55 HIS   (  64-)  A      N      0.08    2.62  INTRA
 163 LEU   ( 184-)  A      CD1 <->  193 GLN   ( 214-)  A      NE2    0.07    3.03  INTRA BF
 308 ALA   ( 333-)  A      CB  <->  309 TYR   ( 334-)  A      N      0.06    2.64  INTRA BL
 351 GLU   ( 376-)  A      O   <->  353 HOH   ( 694 )  A      O      0.06    2.34  INTRA BF
 289 ARG   ( 314-)  A      NH1 <->  353 HOH   ( 669 )  A      O      0.06    2.64  INTRA BF
 289 ARG   ( 314-)  A      N   <->  290 PRO   ( 315-)  A      CD     0.06    2.94  INTRA BL
 277 TRP   ( 302-)  A      CZ2 <->  278 GLN   ( 303-)  A      NE2    0.05    3.05  INTRA
 349 PRO   ( 374-)  A      C   <->  351 GLU   ( 376-)  A      N      0.05    2.85  INTRA BF
  45 LEU   (  54-)  A      N   <->   63 GLU   (  72-)  A      O      0.05    2.65  INTRA
  79 CYS   (  88-)  A    A SG  <->  138 VAL   ( 159-)  A      C      0.05    3.35  INTRA BL
 351 GLU   ( 376-)  A      CG  <->  353 HOH   ( 694 )  A      O      0.04    2.76  INTRA BF
  74 ARG   (  83-)  A      N   <->   96 ILE   ( 105-)  A      O      0.04    2.66  INTRA BF
 163 LEU   ( 184-)  A      N   <->  164 HIS   ( 185-)  A      N      0.04    2.56  INTRA BF
  52 ALA   (  61-)  A      N   <->   53 PRO   (  62-)  A      CD     0.04    2.96  INTRA
 179 HIS   ( 200-)  A      NE2 <->  353 HOH   ( 456 )  A      O      0.04    2.66  INTRA BL
  54 THR   (  63-)  A      C   <->   55 HIS   (  64-)  A      ND1    0.04    2.96  INTRA BF
 171 PRO   ( 192-)  A      O   <->  194 ASP   ( 215-)  A      N      0.03    2.67  INTRA BL
  79 CYS   (  88-)  A    A SG  <->  139 GLY   ( 160-)  A      CA     0.03    3.37  INTRA BL
 102 ARG   ( 123-)  A      NH2 <->  353 HOH   ( 612 )  A      O      0.03    2.67  INTRA BF
 161 ARG   ( 182-)  A      NE  <->  353 HOH   ( 745 )  A      O      0.03    2.67  INTRA BF
   1 SER   (   3-)  A      CA  <->  353 HOH   ( 409 )  A      O      0.03    2.77  INTRA BF
 165 PRO   ( 186-)  A      O   <->  166 ILE   ( 187-)  A      CG2    0.03    2.67  INTRA BF
 218 HIS   ( 239-)  A      N   <->  219 LEU   ( 240-)  A      N      0.03    2.57  INTRA B3
 237 SER   ( 258-)  A      OG  <->  353 HOH   ( 509 )  A      O      0.02    2.38  INTRA
 277 TRP   ( 302-)  A      O   <->  353 HOH   ( 391 )  A      O      0.02    2.38  INTRA
 111 HIS   ( 132-)  A      ND1 <->  353 HOH   ( 558 )  A      O      0.02    2.68  INTRA
  81 LEU   (  90-)  A      O   <->   90 PHE   (  99-)  A      N      0.01    2.69  INTRA BL
 222 ARG   ( 243-)  A      NH2 <->  353 HOH   ( 418 )  A      O      0.01    2.69  INTRA BL
 165 PRO   ( 186-)  A      C   <->  167 GLN   ( 188-)  A      N      0.01    2.89  INTRA BF
 238 GLN   ( 259-)  A      CD  <->  293 PRO   ( 318-)  A      CG     0.01    3.19  INTRA BF

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

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.

 167 GLN   ( 188-)  A      -6.79
 168 ARG   ( 189-)  A      -6.41
 289 ARG   ( 314-)  A      -6.28
 113 ARG   ( 134-)  A      -6.16
 249 GLN   ( 270-)  A      -5.83
  85 GLN   (  94-)  A      -5.80
 304 LYS   ( 329-)  A      -5.66
 163 LEU   ( 184-)  A      -5.58
 220 ARG   ( 241-)  A      -5.52
 166 ILE   ( 187-)  A      -5.48
  29 GLN   (  31-)  A      -5.38
 207 GLU   ( 228-)  A      -5.18
 183 ARG   ( 204-)  A      -5.05

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.

 166 ILE   ( 187-)  A       168 - ARG    189- ( A)         -6.22

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

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.

 295 ALA   ( 320-)  A   -2.84

Warning: Abnormal packing Z-score for sequential residues

A stretch of at least four sequential residues with a 2nd generation packing Z-score below -1.75 was found. This could indicate that these residues are part of a strange loop or that the residues in this range are incomplete, but it might also be an indication of misthreading.

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

 162 LYS   ( 183-)  A     -  165 PRO   ( 186-)  A        -1.89

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

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.

 353 HOH   ( 665 )  A      O      5.11    4.99   26.86
 353 HOH   ( 681 )  A      O    -22.06   25.42   60.05
 353 HOH   ( 751 )  A      O    -19.66   26.99   60.93
 353 HOH   ( 752 )  A      O    -35.64   31.08   34.59

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.

 353 HOH   ( 392 )  A      O
 353 HOH   ( 594 )  A      O
 353 HOH   ( 598 )  A      O
 353 HOH   ( 622 )  A      O
 353 HOH   ( 643 )  A      O
 353 HOH   ( 663 )  A      O
 353 HOH   ( 717 )  A      O
 353 HOH   ( 718 )  A      O
 353 HOH   ( 740 )  A      O

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.

  85 GLN   (  94-)  A
 167 GLN   ( 188-)  A
 218 HIS   ( 239-)  A
 224 GLN   ( 245-)  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.

  59 TRP   (  68-)  A      NE1
  86 THR   (  95-)  A      OG1
  99 ASN   ( 120-)  A      ND2
 138 VAL   ( 159-)  A      N
 166 ILE   ( 187-)  A      N
 167 GLN   ( 188-)  A      NE2
 172 SER   ( 193-)  A      OG
 187 ARG   ( 208-)  A      NH1
 197 GLU   ( 218-)  A      N
 209 ARG   ( 230-)  A      NE
 221 ALA   ( 242-)  A      N
 249 GLN   ( 270-)  A      N
 252 GLN   ( 273-)  A      N
 260 SER   ( 281-)  A      OG
 278 GLN   ( 303-)  A      NE2
 287 ASN   ( 312-)  A      ND2
 346 GLN   ( 371-)  A      NE2

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.

 164 HIS   ( 185-)  A      ND1
 249 GLN   ( 270-)  A      OE1

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.

 353 HOH   ( 446 )  A      O  1.21  K  6 *2
 353 HOH   ( 518 )  A      O  1.05  K  4 *2
 353 HOH   ( 548 )  A      O  0.92  K  4 *2 Ion-B
 353 HOH   ( 586 )  A      O  0.95  K  6 *2 Ion-B
 353 HOH   ( 659 )  A      O  0.87  K  4 *2
 353 HOH   ( 708 )  A      O  0.92  K  4 *2 Ion-B H2O-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.

 110 ASP   ( 131-)  A   H-bonding suggests Asn; but Alt-Rotamer
 180 ASP   ( 201-)  A   H-bonding suggests Asn; 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 :  -0.449
  2nd generation packing quality :  -1.868
  Ramachandran plot appearance   :  -1.952
  chi-1/chi-2 rotamer normality  :  -1.402
  Backbone conformation          :  -1.099

RMS Z-scores, should be close to 1.0:
  Bond lengths                   :   0.272 (tight)
  Bond angles                    :   0.687
  Omega angle restraints         :   0.304 (tight)
  Side chain planarity           :   0.204 (tight)
  Improper dihedral distribution :   0.605
  B-factor distribution          :   0.453
  Inside/Outside distribution    :   0.964

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 : 1.75


Structure Z-scores, positive is better than average:

  1st generation packing quality :  -0.1
  2nd generation packing quality :  -1.6
  Ramachandran plot appearance   :  -3.0
  chi-1/chi-2 rotamer normality  :  -2.0
  Backbone conformation          :  -2.3

RMS Z-scores, should be close to 1.0:
  Bond lengths                   :   0.272 (tight)
  Bond angles                    :   0.687
  Omega angle restraints         :   0.304 (tight)
  Side chain planarity           :   0.204 (tight)
  Improper dihedral distribution :   0.605
  B-factor distribution          :   0.453
  Inside/Outside distribution    :   0.964
==============

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,
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Hydrogen bond networks
    R.W.W.Hooft, C.Sander and G.Vriend,
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      protein structures
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Matthews' Coefficient
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Protein side chain planarity
    R.W.W. Hooft, C. Sander and G. Vriend,
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    J. Appl. Cryst. 29, 714--716 (1996).

Puckering parameters
    D.Cremer and J.A.Pople,
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    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.