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 pdb1kt1.ent

Checks that need to be done early-on in validation

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.

 375 SO4   ( 601-)  A  -
 376 SO4   ( 602-)  A  -

Administrative problems that can generate validation failures

Warning: Plausible side chain atoms detected with zero occupancy

Plausible side chain atoms were detected with (near) zero occupancy

When crystallographers do not see an atom they either leave it out completely, or give it an occupancy of zero or a very high B-factor. WHAT IF neglects these atoms. In this case some atoms were found with zero occupancy, but with coordinates that place them at a plausible position. Although WHAT IF knows how to deal with missing side chain atoms, validation will go more reliable if all atoms are presnt. So, please consider manually setting the occupancy of the listed atoms at 1.0.

   1 LYS   (  28-)  A  -   CG
   1 LYS   (  28-)  A  -   CD
   1 LYS   (  28-)  A  -   CE
   1 LYS   (  28-)  A  -   NZ
   2 LYS   (  29-)  A  -   CD
   2 LYS   (  29-)  A  -   CE
   2 LYS   (  29-)  A  -   NZ
   8 LYS   (  35-)  A  -   CD
   8 LYS   (  35-)  A  -   CE
   8 LYS   (  35-)  A  -   NZ
  13 GLU   (  44-)  A  -   CD
  13 GLU   (  44-)  A  -   OE1
  13 GLU   (  44-)  A  -   OE2
  29 LYS   (  60-)  A  -   CG
  29 LYS   (  60-)  A  -   CD
  29 LYS   (  60-)  A  -   CE
  29 LYS   (  60-)  A  -   NZ
  45 LYS   (  88-)  A  -   CD
  45 LYS   (  88-)  A  -   CE
  45 LYS   (  88-)  A  -   NZ
  74 LYS   ( 121-)  A  -   CG
  74 LYS   ( 121-)  A  -   CD
  74 LYS   ( 121-)  A  -   CE
  74 LYS   ( 121-)  A  -   NZ
  84 GLU   ( 131-)  A  -   CD
And so on for a total of 63 lines.

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: Missing atoms

The atoms listed in the table below are missing from the entry. If many atoms are missing, the other checks can become less sensitive. Be aware that it often happens that groups at the termini of DNA or RNA are really missing, so that the absence of these atoms normally is neither an error nor the result of poor electron density. Some of the atoms listed here might also be listed by other checks, most noticeably by the options in the previous section that list missing atoms in several categories. The plausible atoms with zero occupancy are not listed here, as they already got assigned a non-zero occupancy, and thus are no longer 'missing'.

   2 LYS   (  29-)  A      CG
   8 LYS   (  35-)  A      CG
  13 GLU   (  44-)  A      CG
  45 LYS   (  88-)  A      CG
  69 THR   ( 116-)  A      OG1
  69 THR   ( 116-)  A      CG2
  84 GLU   ( 131-)  A      CG
 204 GLU   ( 251-)  A      CG
 348 GLN   ( 395-)  A      CD
 352 LYS   ( 399-)  A      CG

Warning: B-factors outside the range 0.0 - 100.0

In principle, B-factors can have a very wide range of values, but in practice, B-factors should not be zero while B-factors above 100.0 are a good indicator that the location of that atom is meaningless. Be aware that the cutoff at 100.0 is arbitrary. 'High' indicates that atoms with a B-factor > 100.0 were observed; 'Zero' indicates that atoms with a B-factor of zero were observed.

  26 TYR   (  57-)  A    High
  27 ASN   (  58-)  A    High
  32 ASN   (  63-)  A    High

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) :200.000

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: Tyrosine convention problem

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

  23 TYR   (  54-)  A
  26 TYR   (  57-)  A
  66 TYR   ( 113-)  A
 112 TYR   ( 159-)  A
 231 TYR   ( 278-)  A
 237 TYR   ( 284-)  A
 244 TYR   ( 291-)  A
 280 TYR   ( 327-)  A
 286 TYR   ( 333-)  A
 362 TYR   ( 409-)  A

Warning: Phenylalanine convention problem

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

  36 PHE   (  79-)  A
  82 PHE   ( 129-)  A
 141 PHE   ( 188-)  A
 178 PHE   ( 225-)  A
 186 PHE   ( 233-)  A
 268 PHE   ( 315-)  A
 273 PHE   ( 320-)  A
 320 PHE   ( 367-)  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.

   3 ASP   (  30-)  A
 213 ASP   ( 260-)  A
 294 ASP   ( 341-)  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.

  93 GLU   ( 140-)  A
 145 GLU   ( 192-)  A
 160 GLU   ( 207-)  A
 219 GLU   ( 266-)  A
 261 GLU   ( 308-)  A
 291 GLU   ( 338-)  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.

   1 LYS   (  28-)  A      CA   CB   CG  145.85   15.9
   1 LYS   (  28-)  A      CB   CG   CD  129.05    7.7
  31 ALA   (  62-)  A      N    CA   C    93.63   -6.3
  84 GLU   ( 131-)  A      N    CA   C    99.58   -4.2
 138 ASP   ( 185-)  A      N    CA   C    98.37   -4.6
 178 PHE   ( 225-)  A      N    CA   C    96.69   -5.2
 197 GLU   ( 244-)  A      N    CA   C    99.68   -4.1
 338 LYS   ( 385-)  A      CA   CB   CG  104.91   -4.6
 367 LYS   ( 414-)  A      CA   CB   CG  103.93   -5.1

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.

   3 ASP   (  30-)  A
  93 GLU   ( 140-)  A
 145 GLU   ( 192-)  A
 160 GLU   ( 207-)  A
 213 ASP   ( 260-)  A
 219 GLU   ( 266-)  A
 261 GLU   ( 308-)  A
 291 GLU   ( 338-)  A
 294 ASP   ( 341-)  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.

  31 ALA   (  62-)  A    7.37
 178 PHE   ( 225-)  A    5.61
 251 LEU   ( 298-)  A    4.75
 328 GLU   ( 375-)  A    4.56
 345 PHE   ( 392-)  A    4.26
 351 ALA   ( 398-)  A    4.23
 197 GLU   ( 244-)  A    4.21
 348 GLN   ( 395-)  A    4.13
  84 GLU   ( 131-)  A    4.05

Warning: High tau angle deviations

The RMS Z-score for the tau angles (N-Calpha-C) in the structure is too high. For well refined structures this number is expected to be near 1.0. The fact that it is higher than 1.5 worries us. However, we determined the tau normal distributions from 500 high-resolution X-ray structures, rather than from CSD data, so we cannot be 100 percent certain about these numbers.

Tau angle RMS Z-score : 1.685

Torsion-related checks

Warning: Ramachandran Z-score low

The score expressing how well the backbone conformations of all residues correspond to the known allowed areas in the Ramachandran plot is a bit low.

Ramachandran Z-score : -3.662

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.

  76 PRO   ( 123-)  A    -2.8
  43 VAL   (  86-)  A    -2.6
  36 PHE   (  79-)  A    -2.5
 141 PHE   ( 188-)  A    -2.5
  97 GLU   ( 144-)  A    -2.4
  26 TYR   (  57-)  A    -2.4
  67 GLY   ( 114-)  A    -2.4
  77 SER   ( 124-)  A    -2.3
  72 LEU   ( 119-)  A    -2.3
 139 VAL   ( 186-)  A    -2.2
 153 ILE   ( 200-)  A    -2.2
  70 GLY   ( 117-)  A    -2.2
 319 GLU   ( 366-)  A    -2.2
  27 ASN   (  58-)  A    -2.1
 285 GLU   ( 332-)  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.

   4 ARG   (  31-)  A  Poor phi/psi
  19 GLY   (  50-)  A  Poor phi/psi
  30 LEU   (  61-)  A  Poor phi/psi
  36 PHE   (  79-)  A  Poor phi/psi
  39 GLY   (  82-)  A  Poor phi/psi
  41 GLY   (  84-)  A  Poor phi/psi
  43 VAL   (  86-)  A  Poor phi/psi
  53 THR   (  96-)  A  Poor phi/psi
  67 GLY   ( 114-)  A  Poor phi/psi
  72 LEU   ( 119-)  A  PRO omega poor
  77 SER   ( 124-)  A  Poor phi/psi
  97 GLU   ( 144-)  A  Poor phi/psi
  98 ASP   ( 145-)  A  Poor phi/psi
 150 ASP   ( 197-)  A  Poor phi/psi
 165 GLU   ( 212-)  A  Poor phi/psi
 191 ASN   ( 238-)  A  Poor phi/psi
 284 ARG   ( 331-)  A  Poor phi/psi
 318 ASN   ( 365-)  A  Poor phi/psi
 338 LYS   ( 385-)  A  Poor phi/psi
 chi-1/chi-2 correlation Z-score : -2.429

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 ARG   (  31-)  A      0
   8 LYS   (  35-)  A      0
   9 ILE   (  36-)  A      0
  10 VAL   (  37-)  A      0
  11 HIS   (  42-)  A      0
  12 GLY   (  43-)  A      0
  13 GLU   (  44-)  A      0
  14 GLU   (  45-)  A      0
  16 PRO   (  47-)  A      0
  17 MET   (  48-)  A      0
  18 ILE   (  49-)  A      0
  23 TYR   (  54-)  A      0
  24 VAL   (  55-)  A      0
  25 HIS   (  56-)  A      0
  30 LEU   (  61-)  A      0
  31 ALA   (  62-)  A      0
  32 ASN   (  63-)  A      0
  33 PRO   (  76-)  A      0
  34 PHE   (  77-)  A      0
  38 ILE   (  81-)  A      0
  42 GLN   (  85-)  A      0
  43 VAL   (  86-)  A      0
  44 ILE   (  87-)  A      0
  52 ALA   (  95-)  A      0
  53 THR   (  96-)  A      0
And so on for a total of 124 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 : 1.390

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].

  76 PRO   ( 123-)  A   107.6 envelop C-beta (108 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.

  28 GLY   (  59-)  A      O   <->   29 LYS   (  60-)  A      CG     0.52    2.18  INTRA BF
  31 ALA   (  62-)  A      N   <->   32 ASN   (  63-)  A      N      0.47    2.13  INTRA BF
   8 LYS   (  35-)  A      NZ  <->   58 GLU   ( 101-)  A      OE2    0.42    2.28  INTRA
  66 TYR   ( 113-)  A      CD1 <->   67 GLY   ( 114-)  A      N      0.40    2.60  INTRA BF
 294 ASP   ( 341-)  A      OD1 <->  310 ARG   ( 357-)  A      NH1    0.39    2.31  INTRA BF
  11 HIS   (  42-)  A      ND1 <->   12 GLY   (  43-)  A      N      0.36    2.54  INTRA BF
 108 ARG   ( 155-)  A      NH1 <->  377 HOH   ( 506 )  A      O      0.32    2.38  INTRA BF
 147 GLU   ( 194-)  A      CG  <->  236 LYS   ( 283-)  A      NZ     0.28    2.82  INTRA BF
  72 LEU   ( 119-)  A      N   <->   75 ILE   ( 122-)  A      O      0.26    2.44  INTRA BF
   1 LYS   (  28-)  A      O   <->    3 ASP   (  30-)  A      N      0.25    2.45  INTRA BF
 178 PHE   ( 225-)  A      N   <->  377 HOH   ( 504 )  A      O      0.25    2.45  INTRA BL
 111 GLY   ( 158-)  A      O   <->  163 GLN   ( 210-)  A      NE2    0.24    2.46  INTRA BF
 180 GLU   ( 227-)  A      OE2 <->  191 ASN   ( 238-)  A      ND2    0.24    2.46  INTRA BF
  28 GLY   (  59-)  A      C   <->   29 LYS   (  60-)  A      CG     0.23    2.87  INTRA BF
  39 GLY   (  82-)  A      O   <->  108 ARG   ( 155-)  A      NH2    0.23    2.47  INTRA BF
 369 PHE   ( 416-)  A      O   <->  372 GLN   ( 419-)  A      N      0.23    2.47  INTRA BF
  98 ASP   ( 145-)  A      OD1 <->  100 GLY   ( 147-)  A      N      0.21    2.49  INTRA BF
 351 ALA   ( 398-)  A      O   <->  355 ASN   ( 402-)  A      ND2    0.21    2.49  INTRA BF
  30 LEU   (  61-)  A      CG  <->   31 ALA   (  62-)  A      N      0.20    2.80  INTRA BF
  22 VAL   (  53-)  A      CG1 <->   23 TYR   (  54-)  A      N      0.19    2.81  INTRA BF
  30 LEU   (  61-)  A      C   <->   32 ASN   (  63-)  A      N      0.18    2.72  INTRA BF
  11 HIS   (  42-)  A      CB  <->   56 LYS   (  99-)  A      O      0.17    2.63  INTRA BF
 139 VAL   ( 186-)  A      CG2 <->  140 ALA   ( 187-)  A      N      0.17    2.83  INTRA BL
  40 LYS   (  83-)  A      O   <->   42 GLN   (  85-)  A      N      0.17    2.53  INTRA BF
  17 MET   (  48-)  A      CE  <->  104 ARG   ( 151-)  A      CZ     0.17    3.03  INTRA BF
And so on for a total of 103 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

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.

 112 TYR   ( 159-)  A      -8.10
 255 TYR   ( 302-)  A      -7.67
 108 ARG   ( 155-)  A      -6.99
  42 GLN   (  85-)  A      -6.50
  66 TYR   ( 113-)  A      -6.39
 175 ARG   ( 222-)  A      -5.92
 149 HIS   ( 196-)  A      -5.88
  72 LEU   ( 119-)  A      -5.57
  74 LYS   ( 121-)  A      -5.45
 180 GLU   ( 227-)  A      -5.14
 253 MET   ( 300-)  A      -5.11
   4 ARG   (  31-)  A      -5.05
  97 GLU   ( 144-)  A      -5.04

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: 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

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.

 377 HOH   ( 528 )  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.

  61 HIS   ( 104-)  A
 167 GLN   ( 214-)  A
 314 GLN   ( 361-)  A
 318 ASN   ( 365-)  A
 364 ASN   ( 411-)  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.

  14 GLU   (  45-)  A      N
  24 VAL   (  55-)  A      N
  31 ALA   (  62-)  A      N
  37 SER   (  80-)  A      N
  39 GLY   (  82-)  A      N
  42 GLN   (  85-)  A      N
  43 VAL   (  86-)  A      N
  44 ILE   (  87-)  A      N
  46 ALA   (  89-)  A      N
  47 TRP   (  90-)  A      N
  47 TRP   (  90-)  A      NE1
  51 VAL   (  94-)  A      N
  52 ALA   (  95-)  A      N
  56 LYS   (  99-)  A      N
  72 LEU   ( 119-)  A      N
  74 LYS   ( 121-)  A      N
  80 THR   ( 127-)  A      N
  82 PHE   ( 129-)  A      N
  90 PHE   ( 137-)  A      N
 112 TYR   ( 159-)  A      N
 116 ASN   ( 163-)  A      N
 150 ASP   ( 197-)  A      N
 164 ARG   ( 211-)  A      N
 210 TRP   ( 257-)  A      N
 243 GLN   ( 290-)  A      NE2
 255 TYR   ( 302-)  A      N
 336 GLN   ( 383-)  A      N
 340 ALA   ( 387-)  A      N
 341 ARG   ( 388-)  A      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.

  13 GLU   (  44-)  A      OE1
  20 ASP   (  51-)  A      OD1
  48 ASP   (  91-)  A      OD1
 254 GLU   ( 301-)  A      OE2

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.

  48 ASP   (  91-)  A   H-bonding suggests Asn; but Alt-Rotamer
  97 GLU   ( 144-)  A   H-bonding suggests Gln
  98 ASP   ( 145-)  A   H-bonding suggests Asn
 156 ASP   ( 203-)  A   H-bonding suggests Asn; but Alt-Rotamer
 326 ASP   ( 373-)  A   H-bonding suggests Asn
 358 ASP   ( 405-)  A   H-bonding suggests Asn; but Alt-Rotamer
 373 ASP   ( 420-)  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 :  -0.887
  2nd generation packing quality :  -0.786
  Ramachandran plot appearance   :  -3.662 (poor)
  chi-1/chi-2 rotamer normality  :  -2.429
  Backbone conformation          :   0.296

RMS Z-scores, should be close to 1.0:
  Bond lengths                   :   0.436 (tight)
  Bond angles                    :   0.746
  Omega angle restraints         :   0.253 (tight)
  Side chain planarity           :   0.260 (tight)
  Improper dihedral distribution :   0.624
  B-factor distribution          :   1.300
  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 : 2.80


Structure Z-scores, positive is better than average:

  1st generation packing quality :   0.2
  2nd generation packing quality :   0.8
  Ramachandran plot appearance   :  -1.2
  chi-1/chi-2 rotamer normality  :  -0.3
  Backbone conformation          :   1.1

RMS Z-scores, should be close to 1.0:
  Bond lengths                   :   0.436 (tight)
  Bond angles                    :   0.746
  Omega angle restraints         :   0.253 (tight)
  Side chain planarity           :   0.260 (tight)
  Improper dihedral distribution :   0.624
  B-factor distribution          :   1.300
  Inside/Outside distribution    :   1.053
==============

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.