WHAT IF Check report

This file was created 2011-12-17 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 pdb2od8.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. 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: 2

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

 133 TYR   ( 133-)  A

Warning: Phenylalanine convention problem

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

  57 PHE   (  57-)  A
 185 PHE   ( 185-)  A
 239 PHE   ( 239-)  A
 249 PHE   ( 249-)  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.

  21 ASP   (  21-)  A
  42 ASP   (  42-)  A
  71 ASP   (  71-)  A
  93 ASP   (  93-)  A
  97 ASP   (  97-)  A
 120 ASP   ( 120-)  A
 134 ASP   ( 134-)  A
 172 ASP   ( 172-)  A
 187 ASP   ( 187-)  A
 240 ASP   ( 240-)  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.

  32 GLU   (  32-)  A
  55 GLU   (  55-)  A
 129 GLU   ( 129-)  A
 198 GLU   ( 198-)  A

Geometric checks

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.

 122 ASP   ( 122-)  A     -C    N    CA  129.04    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.

  21 ASP   (  21-)  A
  32 GLU   (  32-)  A
  42 ASP   (  42-)  A
  55 GLU   (  55-)  A
  71 ASP   (  71-)  A
  93 ASP   (  93-)  A
  97 ASP   (  97-)  A
 120 ASP   ( 120-)  A
 129 GLU   ( 129-)  A
 134 ASP   ( 134-)  A
 172 ASP   ( 172-)  A
 187 ASP   ( 187-)  A
 198 GLU   ( 198-)  A
 240 ASP   ( 240-)  A

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.

 125 PHE   ( 125-)  A    -3.2
 137 LEU   ( 137-)  A    -2.5
 139 LEU   ( 139-)  A    -2.4
  95 THR   (  95-)  A    -2.4
 232 GLU   ( 232-)  A    -2.4
   3 GLU   (   3-)  A    -2.2
  31 LYS   (  31-)  A    -2.1
 121 ILE   ( 121-)  A    -2.1
 129 GLU   ( 129-)  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.

  19 PHE   (  19-)  A  omega poor
  31 LYS   (  31-)  A  Poor phi/psi
  44 ARG   (  44-)  A  Poor phi/psi
  51 GLU   (  51-)  A  omega poor
  52 ILE   (  52-)  A  omega poor
  57 PHE   (  57-)  A  omega poor
  84 ASN   (  84-)  A  omega poor
 108 LYS   ( 108-)  A  omega poor
 120 ASP   ( 120-)  A  omega poor
 121 ILE   ( 121-)  A  omega poor
 122 ASP   ( 122-)  A  Poor phi/psi
 123 ALA   ( 123-)  A  Poor phi/psi
 124 ASP   ( 124-)  A  omega poor
 129 GLU   ( 129-)  A  omega poor
 163 THR   ( 163-)  A  Poor phi/psi
 240 ASP   ( 240-)  A  omega poor
 242 LYS   ( 242-)  A  omega poor
 245 PHE   ( 245-)  A  omega poor
 chi-1/chi-2 correlation Z-score : -3.209

Warning: chi-1/chi-2 angle correlation Z-score low

The score expressing how well the chi-1/chi-2 angles of all residues correspond to the populated areas in the database is a bit low.

chi-1/chi-2 correlation Z-score : -3.209

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!

   7 GLU   (   7-)  A      0
   8 GLU   (   8-)  A      0
  19 PHE   (  19-)  A      0
  22 CYS   (  22-)  A      0
  25 LEU   (  25-)  A      0
  27 ASN   (  27-)  A      0
  31 LYS   (  31-)  A      0
  33 ASP   (  33-)  A      0
  43 SER   (  43-)  A      0
  44 ARG   (  44-)  A      0
  52 ILE   (  52-)  A      0
  57 PHE   (  57-)  A      0
  58 GLN   (  58-)  A      0
  59 GLU   (  59-)  A      0
  62 CYS   (  62-)  A      0
  64 HIS   (  64-)  A      0
  65 PRO   (  65-)  A      0
  70 MET   (  70-)  A      0
  81 CYS   (  81-)  A      0
  83 ASN   (  83-)  A      0
  84 ASN   (  84-)  A      0
  85 THR   (  85-)  A      0
  96 PRO   (  96-)  A      0
 107 LYS   ( 107-)  A      0
 108 LYS   ( 108-)  A      0
And so on for a total of 101 lines.

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].

  96 PRO   (  96-)  A   -35.3 envelop C-alpha (-36 degrees)
 252 PRO   ( 252-)  A    38.5 envelop C-delta (36 degrees)
 257 PRO   (  36-)  B    52.2 half-chair C-delta/C-gamma (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.

  38 GLN   (  38-)  A      NE2 <->  126 LEU   ( 126-)  A      O      0.35    2.35  INTRA
  35 ILE   (  35-)  A      N   <->   52 ILE   (  52-)  A      O      0.25    2.45  INTRA
   3 GLU   (   3-)  A      N   <->   61 ARG   (  61-)  A      O      0.16    2.54  INTRA
 187 ASP   ( 187-)  A      OD2 <->  190 HIS   ( 190-)  A      ND1    0.16    2.54  INTRA
 159 ASN   ( 159-)  A      N   <->  170 VAL   ( 170-)  A      O      0.11    2.59  INTRA BL
 194 SER   ( 194-)  A      O   <->  224 ARG   ( 224-)  A      NH2    0.10    2.60  INTRA BL
 137 LEU   ( 137-)  A      O   <->  227 ILE   ( 227-)  A      N      0.09    2.61  INTRA BL
  44 ARG   (  44-)  A      O   <->  262 LEU   (  41-)  B      N      0.09    2.61  INTRA
  10 SER   (  10-)  A      O   <->   14 ARG   (  14-)  A      N      0.08    2.62  INTRA
 160 ILE   ( 160-)  A      N   <->  205 LEU   ( 205-)  A      O      0.08    2.62  INTRA BL
  49 SER   (  49-)  A      O   <->  247 GLN   ( 247-)  A      N      0.07    2.63  INTRA
 251 ALA   ( 251-)  A      O   <->  259 GLN   (  38-)  B      NE2    0.04    2.66  INTRA
 161 MET   ( 161-)  A      N   <->  168 LYS   ( 168-)  A      O      0.03    2.67  INTRA
  27 ASN   (  27-)  A      ND2 <->  121 ILE   ( 121-)  A      O      0.03    2.67  INTRA
 261 THR   (  40-)  B      OG1 <->  264 ARG   (  43-)  B      NH1    0.02    2.68  INTRA BL
  84 ASN   (  84-)  A      CA  <->   85 THR   (  85-)  A      CA     0.02    2.78  INTRA B3
  97 ASP   (  97-)  A      N   <->   98 SER   (  98-)  A      N      0.01    2.59  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

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.

  80 ARG   (  80-)  A      -6.51
 129 GLU   ( 129-)  A      -5.77
 242 LYS   ( 242-)  A      -5.61
 188 MET   ( 188-)  A      -5.55
 107 LYS   ( 107-)  A      -5.46

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.

 254 PHE   ( 254-)  A   -2.55

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: 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.

   7 GLU   (   7-)  A      N
   8 GLU   (   8-)  A      N
  10 SER   (  10-)  A      N
  12 PHE   (  12-)  A      N
  21 ASP   (  21-)  A      N
  33 ASP   (  33-)  A      N
  34 GLY   (  34-)  A      N
  55 GLU   (  55-)  A      N
  64 HIS   (  64-)  A      N
  82 GLY   (  82-)  A      N
  89 THR   (  89-)  A      OG1
 105 ASP   ( 105-)  A      N
 110 ARG   ( 110-)  A      N
 121 ILE   ( 121-)  A      N
 124 ASP   ( 124-)  A      N
 176 GLY   ( 176-)  A      N
 189 GLU   ( 189-)  A      N
 192 GLU   ( 192-)  A      N
 194 SER   ( 194-)  A      OG
 196 LYS   ( 196-)  A      NZ
 208 GLY   ( 208-)  A      N
 230 SER   ( 230-)  A      N
 240 ASP   ( 240-)  A      N

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.

  17 ASP   (  17-)  A   H-bonding suggests Asn
  32 GLU   (  32-)  A   H-bonding suggests Gln
  86 ASP   (  86-)  A   H-bonding suggests Asn; but Alt-Rotamer
  93 ASP   (  93-)  A   H-bonding suggests Asn
 105 ASP   ( 105-)  A   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 :   0.455
  2nd generation packing quality :  -1.272
  Ramachandran plot appearance   :  -1.586
  chi-1/chi-2 rotamer normality  :  -3.209 (poor)
  Backbone conformation          :  -0.127

RMS Z-scores, should be close to 1.0:
  Bond lengths                   :   0.330 (tight)
  Bond angles                    :   0.530 (tight)
  Omega angle restraints         :   1.038
  Side chain planarity           :   0.274 (tight)
  Improper dihedral distribution :   0.523
  B-factor distribution          :   0.355
  Inside/Outside distribution    :   0.975

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 : 2.80


Structure Z-scores, positive is better than average:

  1st generation packing quality :   1.9
  2nd generation packing quality :   0.3
  Ramachandran plot appearance   :   0.8
  chi-1/chi-2 rotamer normality  :  -1.0
  Backbone conformation          :   0.6

RMS Z-scores, should be close to 1.0:
  Bond lengths                   :   0.330 (tight)
  Bond angles                    :   0.530 (tight)
  Omega angle restraints         :   1.038
  Side chain planarity           :   0.274 (tight)
  Improper dihedral distribution :   0.523
  B-factor distribution          :   0.355
  Inside/Outside distribution    :   0.975
==============

WHAT IF
    G.Vriend,
      WHAT IF: a molecular modelling and drug design program,
    J. Mol. Graph. 8, 52--56 (1990).

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.