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.
166 3AO ( 301-) A -
Alternate atom indicators in PDB files are known to often be erroneous. It has been observed that alternate atom indicators are missing, or that there are too many of them. It is common to see that the distance between two atoms that should be covalently bound is far too big, but the distance between the alternate A of one of them and alternate B of the other is proper for a covalent bond. We have discovered many, many ways in which alternate atoms can be abused. The software tries to deal with most cases, but we know for sure that it cannot deal with all cases. If an alternate atom indicator problem is not properly solved, subsequent checks will list errors that are based on wrong coordinate combinations. So, any problem listed in this table should be solved before error messages further down in this report can be trusted.
24 LYS ( 67-) A - 30 LYS ( 73-) A - 116 ILE ( 159-) A - 155 ILE ( 198-) A -
In case any of these residues shows up as poor or bad in checks further down this report, please check the consistency of the alternate atoms in this residue first, correct it yourself if needed, and run the validation again.
30 LYS ( 73-) A - 116 ILE ( 159-) A - 155 ILE ( 198-) A -
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.
6 TYR ( 49-) A 0.80 10 ASP ( 53-) A 0.80 14 LYS ( 57-) A 0.80 22 GLU ( 65-) A 0.90 24 LYS ( 67-) A 0.70 26 ASP ( 69-) A 0.80 43 LYS ( 86-) A 0.70 48 LYS ( 91-) A 0.90 49 GLY ( 92-) A 0.90 54 ARG ( 97-) A 0.80 58 SER ( 101-) A 0.90 66 PHE ( 109-) A 0.90 67 THR ( 110-) A 0.80 68 ASN ( 111-) A 0.90 69 HIS ( 112-) A 0.90 70 ASN ( 113-) A 0.90 71 GLY ( 114-) A 0.95 75 LYS ( 118-) A 0.90 80 SER ( 123-) A 0.90 81 ARG ( 124-) A 0.90 117 LYS ( 160-) A 0.70 119 ASP ( 162-) A 0.90 124 LYS ( 167-) A 0.85 133 GLU ( 176-) A 0.95 135 MET ( 178-) A 0.80 140 LYS ( 183-) A 0.60 144 PHE ( 187-) A 0.90 147 LYS ( 190-) A 0.80 150 ARG ( 193-) A 0.90 153 LYS ( 196-) A 0.90 154 LYS ( 197-) A 0.70 159 ASP ( 202-) A 0.65
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
Warning: More than 5 percent of buried atoms has low B-factor
For normal protein structures, no more than about 1 percent of the B factors
of buried atoms is below 5.0. The fact that this value is much higher in the
current structure could be a signal that the B-factors were restraints or
constraints to too-low values, misuse of B-factor field in the PDB file, or
a TLS/scaling problem. If the average B factor is low too, it is probably a
low temperature structure determination.
Percentage of buried atoms with B less than 5 : 40.28
Note: B-factor plot
The average atomic B-factor per residue is plotted as function of the residue
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
6 TYR ( 49-) A
111 PHE ( 154-) A
10 ASP ( 53-) A 119 ASP ( 162-) A 159 ASP ( 202-) A
RMS Z-score for bond lengths: 0.325
RMS-deviation in bond distances: 0.007
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
| 0.998213 0.000025 0.000054| | 0.000025 0.998028 0.000366| | 0.000054 0.000366 0.996791|Proposed new scale matrix
| 0.017459 0.000000 0.000000| | 0.000000 0.017462 -0.000006| | 0.000000 -0.000004 0.011429|With corresponding cell
A = 57.276 B = 57.266 C = 87.499 Alpha= 89.958 Beta= 90.001 Gamma= 90.001
The CRYST1 cell dimensions
A = 57.379 B = 57.379 C = 87.784 Alpha= 90.000 Beta= 90.000 Gamma= 90.000
(Under-)estimated Z-score: 4.000
Warning: Low bond angle variability
Bond angles were found to deviate less than normal from the standard bond
angles (normal values for protein residues were taken from Engh and Huber
[REF], for DNA/RNA from Parkinson et al [REF]). 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 angles: 0.601
RMS-deviation in bond angles: 1.189
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.
10 ASP ( 53-) A 119 ASP ( 162-) A 159 ASP ( 202-) A
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.
116 ILE ( 159-) A -2.4 59 PHE ( 102-) A -2.3 60 MET ( 103-) A -2.2 108 GLY ( 151-) A -2.1
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.
10 ASP ( 53-) A omega poor 51 THR ( 94-) A omega poor 58 SER ( 101-) A Poor phi/psi 59 PHE ( 102-) A Poor phi/psi 105 ASN ( 148-) A Poor phi/psi 109 SER ( 152-) A Poor phi/psi chi-1/chi-2 correlation Z-score : 0.040
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!
10 ASP ( 53-) A 0 11 ALA ( 54-) A 0 16 LEU ( 59-) A 0 18 ARG ( 61-) A 0 24 LYS ( 67-) A 0 25 ALA ( 68-) A 0 27 VAL ( 70-) A 0 28 VAL ( 71-) A 0 42 GLU ( 85-) A 0 43 LYS ( 86-) A 0 45 PHE ( 88-) A 0 47 TYR ( 90-) A 0 48 LYS ( 91-) A 0 50 SER ( 93-) A 0 52 PHE ( 95-) A 0 53 HIS ( 96-) A 0 54 ARG ( 97-) A 0 57 PRO ( 100-) A 0 58 SER ( 101-) A 0 59 PHE ( 102-) A 0 60 MET ( 103-) A 0 63 ALA ( 106-) A 0 67 THR ( 110-) A 0 69 HIS ( 112-) A 0 70 ASN ( 113-) A 0And so on for a total of 79 lines.
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.
69 HIS ( 112-) A ND1 <-> 167 HOH ( 777 ) A O 0.09 2.61 INTRA BL 64 GLY ( 107-) A N <-> 167 HOH ( 775 ) A O 0.09 2.61 INTRA BL 99 MET ( 142-) A SD <-> 128 PHE ( 171-) A CE1 0.04 3.36 INTRA BL
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.
147 LYS ( 190-) A -5.92 81 ARG ( 124-) A -5.63 78 TYR ( 121-) A -5.13
Chain identifier: A
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.
11 ALA ( 54-) A - 14 LYS ( 57-) A -1.61
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.
167 HOH ( 587 ) A B O 12.84 33.73 27.67 167 HOH ( 623 ) A B O -1.62 6.57 36.20 167 HOH ( 629 ) A B O 1.31 9.68 40.05 167 HOH ( 630 ) A A O -3.12 8.86 13.65
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.
86 ASN ( 129-) A N 93 GLY ( 136-) A N 110 GLN ( 153-) A NE2 116 ILE ( 159-) A N 153 LYS ( 196-) A N
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.
167 HOH ( 535 ) A O 0.86 K 4 167 HOH ( 553 ) A O 1.00 K 4 167 HOH ( 557 ) A O 0.99 K 4 167 HOH ( 564 ) A A O 1.11 MG 5 167 HOH ( 565 ) A O 0.93 K 4 167 HOH ( 570 ) A O 1.01 K 4 167 HOH ( 587 ) A A O 1.04 MG 4 167 HOH ( 655 ) A A O 0.93 MG 6 167 HOH ( 718 ) A O 0.92 K 4
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 : -0.391 2nd generation packing quality : -1.709 Ramachandran plot appearance : -0.088 chi-1/chi-2 rotamer normality : 0.040 Backbone conformation : -0.257
Bond lengths : 0.325 (tight) Bond angles : 0.601 (tight) Omega angle restraints : 1.130 Side chain planarity : 0.454 (tight) Improper dihedral distribution : 0.550 Inside/Outside distribution : 0.919
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 : 1.10
Structure Z-scores, positive is better than average:
1st generation packing quality : -0.0 2nd generation packing quality : -1.5 Ramachandran plot appearance : -0.5 chi-1/chi-2 rotamer normality : -0.5 Backbone conformation : -0.5
Bond lengths : 0.325 (tight) Bond angles : 0.601 (tight) Omega angle restraints : 1.130 Side chain planarity : 0.454 (tight) Improper dihedral distribution : 0.550 Inside/Outside distribution : 0.919 ==============
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.