WHAT IF Check report

This file was created 1997-08-24 from WHAT_CHECK output by a conversion script. If you are new to WHAT_CHECK, please read the introduction to the output.

Verification log for georg\_em.pdb

Symmetry related problems

Warning: Class of space group could be incorrect

The space group symbol indicates a different class than the unit cell given on the CRYST1 card of the PDB file.

Possible cause: The unit cell may have pseudo-symmetry, or one of the cell dimensions or the space group might be given incorrectly.

Crystal class of the cell: CUBIC

Crystal class of the space group: TRICLINIC

Space group name: P 1

Atom coordinate problems and/or unexpected atoms

Note: No rounded coordinates detected

No significant rounding of atom coordinates has been detected.

Symmetry related problems

Error: Matthews Coefficient (Vm) very high

The Matthews coefficient [REF] is defined as the density of the protein structure in cubic Angstroms per Dalton. Normal values are between 1.5 (tightly packed, little room for solvent) and 4.0 (loosely packed, much space for solvent). Some very loosely packed structures can get values a bit higher than that.

Numbers this high are almost always caused by giving the wrong value for Z on the CRYST1 card.

Molecular weight of all polymer chains: 16206.122
Volume of the Unit Cell V= 0.1000E+10
Cell multiplicity: 0
Matthews coefficient for observed atoms Vm= 61705.066

Nomenclature related problems

Note: Valine nomenclature OK

No errors were detected in valine nomenclature.

Note: Threonine nomenclature OK

No errors were detected in threonine nomenclature.

Note: Isoleucine nomenclature OK

No errors were detected in isoleucine nomenclature.

Note: Leucine nomenclature OK

No errors were detected in leucine nomenclature.

Note: Arginine nomenclature OK

No errors were detected in arginine nomenclature.

Note: Tyrosine torsion conventions OK

No errors were detected in tyrosine torsion angle conventions.

Note: Phenylalanine torsion conventions OK

No errors were detected in phenylalanine torsion angle conventions.

Note: Aspartic acid torsion conventions OK

No errors were detected in aspartic acid torsion angle conventions.

Note: Glutamic acid torsion conventions OK

No errors were detected in glutamic acid torsion angle conventions.

Note: Heavy atom naming OK

No errors were detected in the atom names for non-hydrogen atoms.

Warning: Chirality deviations detected

The atoms listed in the table below have an improper dihedral value that is deviating from expected values.

Improper dihedrals are a measure of the chirality/planarity of the structure at a specific atom. Values around -35 or +35 are expected for chiral atoms, and values around 0 for planar atoms. Planar side chains are left out of the calculations, these are better handled by the planarity checks.

Three numbers are given for each atom in the table. The first is the Z-score for the improper dihedral. The second number is the measured improper dihedral. The third number is the expected value for this atom type. A final column contains an extra warning if the chirality for an atom is opposite to the expected value.

  26 GLU  (  26 )      C        4.4      8.7      0.0
  28 ILE  (  28 )      CA      -4.4     24.7     33.8
  31 SER  (  31 )      C        4.6      9.0      0.0
  35 ASP  (  35 )      C        5.6     10.6      0.0
  41 THR  (  41 )      C        4.3      8.4     -0.1
  42 ASN  (  42 )      C        4.1      7.8      0.0
  59 TYR  (  59 )      C        8.4     15.6     -0.1
  63 HIS  (  63 )      C       -4.6     -9.1      0.0
  65 ASN  (  65 )      C        6.6     12.5      0.0
  74 SER  (  74 )      C        4.6      8.9      0.0
  82 GLU  (  82 )      C       -4.7     -9.4      0.0
  86 TYR  (  86 )      CA      -4.4     24.7     34.6
  91 GLN  (  91 )      C        4.9      9.3     -0.1
 104 GLY  ( 104 )      C        4.2      7.3      0.1
 108 GLY  ( 108 )      C        5.8      9.9      0.1
 116 VAL  ( 116 )      CA      -4.4     24.0     33.6
 118 GLY  ( 118 )      C       -4.1     -6.8      0.1
 120 VAL  ( 120 )      C        4.2      8.2     -0.2
 121 THR  ( 121 )      C        6.7     13.2     -0.1
 132 ASP  ( 132 )      C        5.3     10.0      0.0
 138 CYS  ( 138 )      C        4.2      7.8     -0.1
 141 GLU  ( 141 )      C        4.4      8.7      0.0

Warning: High improper dihedral angle deviations

The RMS Z-score for the improper dihedrals in the structure is high. For well refined structures this number is expected to be around 1.0. The fact that it is higher than 1.5 in this structure could be an indication of overrefinement.

Improper dihedral RMS Z-score : 2.018

Note: Chain names are OK

All chain names assigned to polymer molecules are unique, and all residue numbers are strictly increasing within each chain.

Note: Weights checked OK

All atomic occupancy factors ('weights') fall in the 0.0--1.0 range.

Geometric checks

Note: No missing atoms detected

All expected atoms are present.

Note: OXT check OK

All required C-terminal oxygen atoms are present.

Note: No extra C-terminal groups found

No C-terminal groups are present for non C-terminal residues

Note: All bond lengths OK

All bond lengths are in agreement with standard bond lengths using a tolerance of 4 sigma (both standard values and sigma for amino acid residues have been taken from Engh and Huber [REF], for DNA/RNA from Parkinson et al [REF])

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 around 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 constraints have been used in the refinement. This can only be a problem for high resolution X-ray structures.

RMS Z-score for bond lengths: 0.621
RMS-deviation in bond distances: 0.012

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\% 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 lambda 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 constrained to obey the space group symmetry. This is done on purpose. The distortions can give you an indication of the accuracy of the determination.

Unit Cell deformation matrix

 |  0.998859 -0.000293 -0.000242|
 | -0.000293  0.996758 -0.000909|
 | -0.000242 -0.000909  0.996220|
Proposed new scale matrix

 |  0.001001  0.000000  0.000000|
 |  0.000000  0.001003  0.000001|
 |  0.000000  0.000001  0.001004|
With corresponding cell

    A    = 998.859  B   = 996.759  C    = 996.220
    Alpha=  90.105  Beta=  90.028  Gamma=  90.034

The CRYST1 cell dimensions

    A    =1000.000  B   =1000.000  C    =1000.000
    Alpha=  90.000  Beta=  90.000  Gamma=  90.000

Variance: 39.670
(Under-)estimated Z-score: 4.642

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.

  16 ASN  (  16 )      ND2  CG   OD1 118.391  -4.2
  17 LEU  (  17 )      C    CA   CB  117.806   4.1
  20 PHE  (  20 )      CA   CB   CG  120.544   6.7
  21 ASN  (  21 )      CA   CB   CG  117.731   5.1
  35 ASP  (  35 )      CA   CB   CG  117.513   4.9
  39 TYR  (  39 )      CB   CG   CD2 114.693  -4.1
  41 THR  (  41 )     <C    N    CA  129.501   4.3
  41 THR  (  41 )      CA   CB   CG2 117.988   4.4
  46 ASP  (  46 )      CA   CB   CG  116.795   4.2
  65 ASN  (  65 )     <C    N    CA  129.128   4.1
  86 TYR  (  86 )      CA   C    O   113.551  -4.3
  86 TYR  (  86 )      C    CA   CB  119.098   4.7
  87 PRO  (  87 )     <CA  <C    N   125.823   5.9
  87 PRO  (  87 )      N    CA   CB  107.403   4.0
  89 HIS  (  89 )      CG   ND1  CE1 109.639   4.0
 105 ASP  ( 105 )      CA   CB   CG  116.811   4.2
 116 VAL  ( 116 )     <CA  <C    N   124.909   4.1
 116 VAL  ( 116 )     <C    N    CA  135.982   7.9
 116 VAL  ( 116 )      N    CA   CB  122.762   7.2
 119 ILE  ( 119 )      CA   CB   CG1 120.328   5.8
 121 THR  ( 121 )      C    CA   CB  102.184  -4.2
 126 ASN  ( 126 )      CA   CB   CG  116.870   4.3
 127 HIS  ( 127 )      CA   CB   CG  118.551   4.8
 131 ILE  ( 131 )      CA   CB   CG1 118.108   4.5
 136 PHE  ( 136 )      CA   CB   CG  120.325   6.5

Note: Normal bond angle variability

Bond angles were found to deviate normally from the mean 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 around 1.0 for a normally restrained data set, and this is indeed observed for very high resolution X-ray structures. More common values are around 1.55

RMS Z-score for bond angles: 1.476
RMS-deviation in bond angles: 2.624

Error: Side chain planarity problems

The side chains of the residues listed in the table below contain a planar group that was found to deviate from planarity by more than 4.0 times the expected value. For an amino acid residue that has a side chain with a planar group, the RMS deviation of the atoms to a least squares plane was determined. The number in the table is the number of standard deviations this RMS value deviates from the expected value (0.0).

  76 ASP  (  76 )     4.541
  16 ASN  (  16 )     4.315

Error: Connections to aromatic rings out of plane

The atoms listed in the table below are connected to a planar aromatic group in the sidechain of a protein residue but were found to deviate from the least squares plane.

For all atoms that are connected to an aromatic side chain in a protein residue the distance of the atom to the least squares plane through the aromatic system was determined. This value was divided by the standard deviation from a distribution of similar values from a database of small molecule structures.

 127 HIS  ( 127 )      CB   9.990
  59 TYR  (  59 )      CB   8.950
  39 TYR  (  39 )      OH   7.136
  78 TYR  (  78 )      OH   6.475
  14 TYR  (  14 )      OH   6.283
  48 TYR  (  48 )      CB   5.763
  60 TYR  (  60 )      CB   4.410
  89 HIS  (  89 )      CB   4.246
  78 TYR  (  78 )      CB   4.011

Note: PRO puckering amplitude OK

Puckering amplitudes for all PRO residues are within normal ranges.

Note: PRO puckering phases OK

Puckering phases for all PRO residues are normal

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.

  89 HIS  (  89 )   -2.8679
  41 THR  (  41 )   -2.7546
 116 VAL  ( 116 )   -2.5762
  73 THR  (  73 )   -2.4135
  59 TYR  (  59 )   -2.2944
 111 LEU  ( 111 )   -2.2149
  37 ILE  (  37 )   -2.1666
  15 ARG  (  15 )   -2.1658
 119 ILE  ( 119 )   -2.1465
 115 GLY  ( 115 )   -2.1352
  47 ASP  (  47 )   -2.1294
  44 VAL  (  44 )   -2.1225
  29 LEU  (  29 )   -2.1106
  84 GLU  (  84 )   -2.0847
 110 LEU  ( 110 )   -2.0714
 124 GLY  ( 124 )   -2.0161
 118 GLY  ( 118 )   -2.0007

Warning: Backbone torsion angle evaluation shows 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.

   5 MET  (   5 )   Poor phi/psi
   9 VAL  (   9 )   Poor phi/psi
  26 GLU  (  26 )   omega poor
  27 SER  (  27 )   omega poor
  30 VAL  (  30 )   omega poor
  32 TYR  (  32 )   Poor phi/psi
  36 LEU  (  36 )   omega poor
  41 THR  (  41 )   Poor phi/psi, omega poor
  43 THR  (  43 )   omega poor
  47 ASP  (  47 )   Poor phi/psi
  57 ALA  (  57 )   omega poor
  59 TYR  (  59 )   omega poor
  60 TYR  (  60 )   omega poor
  65 ASN  (  65 )   omega poor
  66 ARG  (  66 )   Poor phi/psi
  69 PRO  (  69 )   Poor PRO-phi
  74 SER  (  74 )   Poor phi/psi
  84 GLU  (  84 )   Poor phi/psi
  86 TYR  (  86 )   Poor phi/psi
  87 PRO  (  87 )   Poor PRO-phi
  89 HIS  (  89 )   Poor phi/psi
  93 ASN  (  93 )   Poor phi/psi
 108 GLY  ( 108 )   omega poor
 115 GLY  ( 115 )   omega poor
 116 VAL  ( 116 )   Poor phi/psi, omega poor
 118 GLY  ( 118 )   omega poor
 125 ASP  ( 125 )   Poor phi/psi
 126 ASN  ( 126 )   omega poor

Warning: Ramachandran Z-score low

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

Ramachandran Z-score : -3.205

Warning: Omega angle restraints not strong enough

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

Standard deviation of omega values : 10.850

Note: chi-1/chi-2 angle correlation Z-score OK

The score expressing how well the chi-1/chi-2 angles of all residues are corresponding to the populated areas in the database is within expected ranges for well-refined structures.

chi-1/chi-2 correlation Z-score : -2.896

Note: Ramachandran plot

In this Ramachandran plot X-signs represent glycines, squares represent prolines and small plus-signs represent the other residues. If too many plus-signs fall outside the contoured areas then the molecule is poorly refined (or worse).

In a colour picture, the residues that are part of a helix are shown in blue, strand residues in red. "Allowed" regions for helical residues are drawn in blue, for strand residues in red, and for all other residues in green.

Chain without chain identifier

Accessibility related checks

Note: Inside/Outside residue distribution normal

The distribution of residue types over the inside and the outside of the protein is normal.

inside/outside RMS Z-score : 1.118

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 without chain identifier

Secondary structure

Note: Secondary structure

This is the secondary structure according to DSSP. Only helix (H), strand (S), turn (T) and coil (blank) are shown. [REF]
DBG> SSBOND cards to be written: 0
                     10        20        30        40        50        60
                      |         |         |         |         |         |
    1 -  60  GPSDMYVHVGNLIYRNLHLFNSEMHESILVSYSSDLIIYRTNTVGDDYIPSCDCTQATYY
    1 -  60        SSTTTSSSSSHHHHHT 333 SSSSTTTTSSSSS      T   TT     TT
                     70        80        90       100       110       120
                      |         |         |         |         |         |
   61 - 120  CKHKNRYFPITVTSHDWYEIQESEYYPKHIQYNLLIGEGPCEPGDCGGKLLCKHGVIGIV
   61 - 120   SSSTTSS      HHHHHHH T  TTT    TSSSST    TT TT SSS TTT SSSS
                    130       140
                      |         |
  121 - 142  TAGGDNHVAFIDLRHFHCAEEQ
  121 - 142  SSSSTTTSSSSSHHHHHHHTT
 
 
 

Bump checks

Error: Abnormally short interatomic distances

The pairs of atoms listed in the table below have an unusually short distance.

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 centers of the two atoms.

The last text-item on each line represents the status of the atom pair. The text `INTRA' means that the bump is between atoms that are explicitly listed in the PDB file. `INTER' means it is an inter-symmetry bump. If the final column contains the text 'HB', the bump criterium 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). If the last column is 'BF', the sum of the B-factors of the atoms is higher than 80, which makes the appearance of the bump somewhat less severe because the atoms probably aren't there anyway.

Bumps between atoms for which the sum of their occupancies is lower than one are not reported. In any case, each bump is listed in only one direction.

 112 CYS  ( 112 )      SG   --  114 HIS  ( 114 )      ND1    0.107   3.193 INTRA
   5 MET  (   5 )      SD   --  107 GLY  ( 107 )      O      0.096   2.904 INTRA
 137 HIS  ( 137 )      CG   --  138 CYS  ( 138 )      N      0.079   3.021 INTRA
   5 MET  (   5 )      CG   --    6 TYR  (   6 )      N      0.057   3.043 INTRA
   8 HIS  (   8 )      O    --    9 VAL  (   9 )      C      0.042   2.758 INTRA
 138 CYS  ( 138 )      SG   --  139 ALA  ( 139 )      N      0.013   3.287 INTRA
 119 ILE  ( 119 )      CG2  --  131 ILE  ( 131 )      C      0.001   3.199 INTRA

3D-database related checks

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.

  86 TYR  (  86 )    -7.52
  59 TYR  (  59 )    -6.27
 113 LYS  ( 113 )    -6.11
  92 TYR  (  92 )    -5.98
 114 HIS  ( 114 )    -5.24
  56 GLN  (  56 )    -5.22
  48 TYR  (  48 )    -5.02

Note: No series of residues with bad packing environment

There are no stretches of three or more residues each having a quality control score worse than -4.0.

Warning: Structural average packing environment a bit worrysome

The structural average quality control value is a bit low.

The protein is probably threaded correctly, but either poorly refined, or it is just a protein with an unusual (but correct) structure. The average quality of 200 highly refined Xray structures was -0.5+/-0.4 [REF].

Average for range 1 - 142 : -1.735

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 without chain identifier

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 quality 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.

  25 HIS  (  25 )    -3.12
 114 HIS  ( 114 )    -3.05
  86 TYR  (  86 )    -2.74
  24 MET  (  24 )    -2.57
  90 ILE  (  90 )    -2.53

Note: No series of residues with abnormal new packing environment

There are no stretches of four or more residues each having a quality control Z-score worse than -1.75.

Error: Abnormal structural average packing Z-score

The quality control Z-score for the structure is very low.

A molecule is certain to be incorrect if the Z-score is below -5.0. Poorly refined molecules, very well energy minimized misthreaded molecules and low homology models give values between -2.0 and -5.0. The average quality of properly refined Xray structures is 0.0+/-1.0.

All contacts : Average = -0.798 Z-score = -5.13
BB-BB contacts : Average = -0.226 Z-score = -1.61
BB-SC contacts : Average = -0.773 Z-score = -4.16
SC-BB contacts : Average = -0.419 Z-score = -2.38
SC-SC contacts : Average = -0.927 Z-score = -4.79

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 without chain identifier

Warning: Backbone oxygen evaluation

The residues listed in the table below have an unusual backbone oxygen position.

For each of the residues in the structure, a search was performed to find 5-residue stretches in the WHAT IF database with superposable C-alpha coordinates, and some constraints on the neighboring backbone oxygens.

In the following table the RMS distance between the backbone oxygen positions of these matching structures in the database and the position of the backbone oxygen atom in the current residue is given. If this number is larger than 1.5 a significant number of structures in the database show an alternative position for the backbone oxygen. If the number is larger than 2.0 most matching backbone fragments in the database have the peptide plane flipped. A manual check needs to be performed to assess whether the experimental data can support that alternative as well. The number in the last column is the number of database hits (maximum 80) used in the calculation. It is "normal" that some glycine residues show up in this list, but they are still worth checking!

 124 GLY  ( 124 )    2.71   12
  44 VAL  (  44 )    1.63   17
  69 PRO  (  69 )    1.54   11

Warning: Unusual rotamers

The residues listed in the table below have a rotamer that is not seen very often in the database of solved protein structures. This option determines for every residue the position specific chi-1 rotamer distribution. Thereafter it verified whether the actual residue in the molecule has the most preferred rotamer or not. If the actual rotamer is the preferred one, the score is 1.0. If the actual rotamer is unique, the score is 0.0. If there are two preferred rotamers, with a population distribution of 3:2 and your rotamer sits in the lesser populated rotamer, the score will be 0.66. No value will be given if insufficient hits are found in the database.

It is not necessarily an error if a few residues have rotamer values below 0.3, but careful inspection of all residues with these low values could be worth it.

  31 SER  (  31 )     0.35
  38 ILE  (  38 )     0.40

Warning: Unusual backbone conformations

For the residues listed in the table below, the backbone formed by itself and two neighboring 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 center.

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!

   5 MET  (   5 )    0
   9 VAL  (   9 )    0
  24 MET  (  24 )    0
  32 TYR  (  32 )    0
  41 THR  (  41 )    0
  47 ASP  (  47 )    0
  60 TYR  (  60 )    0
  64 LYS  (  64 )    0
  65 ASN  (  65 )    0
  66 ARG  (  66 )    0
  74 SER  (  74 )    0
  85 TYR  (  85 )    0
  89 HIS  (  89 )    0
 116 VAL  ( 116 )    0
 119 ILE  ( 119 )    0
 125 ASP  ( 125 )    0
  27 SER  (  27 )    1
  29 LEU  (  29 )    1
  73 THR  (  73 )    1
  86 TYR  (  86 )    1
 106 CYS  ( 106 )    1
 122 ALA  ( 122 )    1
  28 ILE  (  28 )    2
  40 ARG  (  40 )    2
  61 CYS  (  61 )    2
 114 HIS  ( 114 )    2
 126 ASN  ( 126 )    2
 127 HIS  ( 127 )    2

Error: Backbone conformation Z-score very low

A comparison of the backbone conformation with database proteins shows that the backbone fold in this structure is very unusual.

Backbone conformation Z-score : -6.189

B-factor analysis

Warning: Average B-factor problem

The average B-factor for all buried protein atoms normally lies between 10--20. Values around 3--5 are expected for X-ray studies performed at liquid nitrogen temperature.

Because of the extreme value for the average B-factor, no further analysis of the B-factors is performed.

Average B-factor for buried atoms : 0.000

Warning: B-factor plot impossible

All average B-factors are zero. Plot suppressed.

Chain without chain identifier

Hydrogen bond related checks

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 favorable 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. If a residue is marked ``flexible'' the flipped conformation is only slightly better than the non-flipped conformation.

  65 ASN  (  65 )
  81 GLN  (  81 )
 127 HIS  ( 127 )
 137 HIS  ( 137 )

Note: Histidine type assignments

For all complete HIS residues in the structure a tentative assignment to HIS-D (protonated on ND1), HIS-E (protonated on NE2), or HIS-H (protonated on both ND1 and NE2, positively charged) is made based on the hydrogen bond network. A second assignment is made based on which of the Engh and Huber [REF] histidine geometries fits best to the structure.

In the table below all normal histidine residues are listed. The assignment based on the geometry of the residue is listed first, together with the RMS Z-score for the fit to the Engh and Huber parameters. For all residues where the H-bond assignment is different, the assignment is listed in the last columns, together with its RMS Z-score to the Engh and Huber parameters.

As always, the RMS Z-scores should be close to 1.0 if the residues were restrained to the Engh and Huber parameters during refinement.

Please note that because the differences between the geometries of the different types are small it is possible that the geometric assignment given here does not correspond to the type used in refinement. This is especially true if the RMS Z-scores are much higher than 1.0.

If the two assignments differ, or the ``geometry'' RMS Z-score is high, it is advisable to verify the hydrogen bond assignment, check the HIS type used during the refinement and possibly adjust it.

   8 HIS  (   8 )     HIS-E   1.67
  18 HIS  (  18 )     HIS-E   1.95
  25 HIS  (  25 )     HIS-E   1.95
  63 HIS  (  63 )     HIS-E   1.91 HIS-D   2.47
  75 HIS  (  75 )     HIS-E   2.02
  89 HIS  (  89 )     HIS-E   1.82
 114 HIS  ( 114 )     HIS-E   1.74
 127 HIS  ( 127 )     HIS-E   1.75 HIS-D   2.45
 135 HIS  ( 135 )     HIS-E   1.86
 137 HIS  ( 137 )     HIS-E   1.72 HIS-D   2.22

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.

   6 TYR  (   6 )      N
   8 HIS  (   8 )      NE2
  16 ASN  (  16 )      N
  16 ASN  (  16 )      ND2
  30 VAL  (  30 )      N
  44 VAL  (  44 )      N
  56 GLN  (  56 )      N
  65 ASN  (  65 )      ND2
  74 SER  (  74 )      N
  84 GLU  (  84 )      N
  85 TYR  (  85 )      OH
  86 TYR  (  86 )      N
  90 ILE  (  90 )      N
  91 GLN  (  91 )      N
  91 GLN  (  91 )      NE2
  92 TYR  (  92 )      N
  96 ILE  (  96 )      N
  99 GLY  (  99 )      N
 102 GLU  ( 102 )      N
 106 CYS  ( 106 )      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 that are 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.

   8 HIS  (   8 )      ND1
  81 GLN  (  81 )      OE1
  82 GLU  (  82 )      OE1
 142 GLN  ( 142 )      OE1

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 constraint values. The first part of the table shows a number of constraint-independent quality indicators.


Structure Z-scores, positive is better than average:

  1st generation packing quality :  -3.088
  2nd generation packing quality :  -5.126 (bad)
  Ramachandran plot appearance   :  -3.205 (poor)
  chi-1/chi-2 rotamer normality  :  -2.896
  Backbone conformation          :  -6.189 (bad)

RMS Z-scores, should be close to 1.0:
  Bond lengths                   :   0.621 (tight)
  Bond angles                    :   1.476
  Omega angle restraints         :   1.973 (loose)
  Side chain planarity           :   1.600
  Improper dihedral distribution :   2.018 (loose)
  Inside/Outside distribution    :   1.118