Contacts of the helix formed by residues 134 - 157 (chain Q) in PDB entry 1H2I


Residue contacts within the protein are derived with the CSU software (Sobolev V., Sorokine A., Prilusky J., Abola E.E. and Edelman M. (1999) Automated analysis of interatomic contacts in proteins. Bioinformatics, 15, 327-332). A short description of the analytical approach is given at the end of the page.
For CSU analysis of other PDB entry

Note:
Non-standard 3 letter residue codes indicate a heterogroup. To identify and analyse, use LPC software

Legend:
Dist - nearest distance (Å) between atoms of two residues
Surf - contact surface area (Å2) between two residues
HB   - hydrophilic-hydrophilic contact (hydrogen bond)
Arom - aromatic-aromatic contact
Phob - hydrophobic-hydrophobic contact
DC   - hydrophobic-hydrophilic contact (destabilizing contact)
+/-  - indicates presence/absence of a specific contacts
*    - indicates residues forming contacts  by their side chain
       (including CA atoms)
Residues in contact with SER 134 (chain Q).
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    103Q  PHE*     3.8     1.3    -      -       -      -
    132Q  LEU*     3.3     2.7    -      -       -      +
    133Q  LYS*     1.3    78.2    -      -       -      +
    135Q  LYS*     1.3    63.5    +      -       -      +
    136Q  ALA      3.7     0.2    +      -       -      -
    137Q  LEU*     3.2    38.7    +      -       -      +
    138Q  SER*     3.0    26.2    +      -       -      -
    130R  GLU*     3.0    25.9    +      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with LYS 135 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     96Q  VAL*     4.3    15.0    -      -       +      -
    103Q  PHE*     3.5    48.4    -      -       +      -
    105Q  VAL*     6.4     0.2    -      -       +      -
    133Q  LYS      3.7     0.2    +      -       -      -
    134Q  SER*     1.3    72.0    +      -       -      +
    136Q  ALA*     1.3    65.5    +      -       -      +
    138Q  SER*     3.0     4.1    +      -       -      -
    139Q  LEU*     2.9    33.3    +      -       +      +
     95R  PHE*     3.7    37.8    -      -       +      +
     97R  ASP*     2.9    34.6    +      -       -      +
    130R  GLU*     5.0     1.2    +      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 136 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    134Q  SER*     3.7     0.4    +      -       -      +
    135Q  LYS*     1.3    79.8    -      -       -      +
    137Q  LEU*     1.3    58.5    +      -       +      +
    139Q  LEU*     3.8     2.0    -      -       -      +
    140Q  GLU*     2.9    31.3    +      -       -      +
     95R  PHE*     3.5    24.9    -      -       +      -
    105R  VAL      4.6     2.2    -      -       -      +
    126R  TYR*     3.8     8.6    -      -       +      -
    128R  VAL*     3.7    37.0    -      -       +      -
    130R  GLU*     3.9    13.9    +      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with LEU 137 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    132Q  LEU*     4.1    17.2    -      -       +      +
    134Q  SER*     3.2    29.6    +      -       -      +
    135Q  LYS      3.3     0.2    -      -       -      -
    136Q  ALA*     1.3    84.3    -      -       +      +
    138Q  SER*     1.3    57.7    +      -       -      +
    140Q  GLU*     3.6    22.0    -      -       -      +
    141Q  LYS*     3.1    28.2    +      -       -      +
    128R  VAL*     4.9     7.6    -      -       +      -
    130R  GLU*     4.1    13.7    -      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with SER 138 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    103Q  PHE*     3.8    16.3    +      -       -      +
    105Q  VAL*     3.8    22.0    -      -       -      -
    129Q  SER*     3.2    30.5    +      -       -      -
    132Q  LEU*     3.4    15.6    -      -       -      +
    134Q  SER      3.0    21.5    +      -       -      -
    135Q  LYS*     3.0     5.5    +      -       -      -
    137Q  LEU*     1.3    75.2    -      -       -      +
    139Q  LEU*     1.3    64.5    +      -       -      +
    141Q  LYS      3.3     0.9    +      -       -      -
    142Q  ALA*     3.0    21.1    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with LEU 139 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     93Q  VAL*     4.5    17.7    -      -       +      -
     96Q  VAL*     4.0    21.5    -      -       +      -
    105Q  VAL*     3.6    26.5    -      -       +      -
    107Q  VAL*     4.7     2.5    -      -       +      -
    135Q  LYS*     2.9    27.4    +      -       +      +
    136Q  ALA      3.8     1.1    -      -       -      +
    138Q  SER*     1.3    76.0    -      -       -      +
    140Q  GLU*     1.3    58.9    +      -       -      +
    142Q  ALA*     3.3     1.4    +      -       -      +
    143Q  ARG*     2.8    38.1    +      -       +      +
     94R  ASP*     3.5    24.0    -      -       +      +
     95R  PHE*     4.0    24.9    -      -       +      -
    126R  TYR*     3.5    15.0    -      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with GLU 140 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    136Q  ALA      2.9    16.1    +      -       -      +
    137Q  LEU*     3.6    27.3    -      -       -      +
    139Q  LEU*     1.3    77.3    -      -       -      +
    141Q  LYS*     1.3    65.0    +      -       -      +
    143Q  ARG*     4.1     0.8    -      -       -      -
    144Q  LYS*     3.0    60.9    +      -       +      +
    126R  TYR*     3.7    34.1    -      -       +      +
    128R  VAL*     4.8     7.0    -      -       -      +
    149R  ASP*     4.5     1.0    -      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with LYS 141 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    128Q  VAL      2.6    27.5    +      -       -      +
    129Q  SER*     4.0    13.7    -      -       -      +
    132Q  LEU*     5.0     7.9    -      -       +      -
    137Q  LEU      3.1    19.1    +      -       -      +
    138Q  SER      3.8     3.8    -      -       -      +
    139Q  LEU      3.3     0.2    -      -       -      -
    140Q  GLU*     1.3    79.4    -      -       -      +
    142Q  ALA*     1.3    63.6    +      -       -      +
    144Q  LYS*     4.1     2.5    -      -       -      +
    145Q  GLU*     2.9    59.3    +      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 142 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    105Q  VAL*     3.9    15.3    -      -       +      +
    107Q  VAL*     3.8    17.6    -      -       +      +
    127Q  GLY*     3.3    34.5    -      -       -      +
    128Q  VAL      4.1     5.8    -      -       -      +
    129Q  SER      4.4     0.2    -      -       -      +
    138Q  SER      3.0    17.0    +      -       -      +
    139Q  LEU      3.9     0.9    -      -       -      +
    141Q  LYS*     1.3    76.0    -      -       -      +
    143Q  ARG*     1.3    67.1    +      -       -      +
    146Q  ALA*     3.0    21.5    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ARG 143 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     91Q  GLN*     2.8    61.6    +      -       -      +
     93Q  VAL*     3.5    27.6    -      -       -      +
    107Q  VAL*     4.1    13.0    -      -       +      -
    139Q  LEU*     2.8    26.5    +      -       +      +
    140Q  GLU*     4.2     2.9    -      -       -      +
    142Q  ALA*     1.3    73.7    -      -       -      +
    144Q  LYS*     1.3    64.7    +      -       +      +
    146Q  ALA      3.3     0.2    +      -       -      -
    147Q  VAL*     3.3    11.4    +      -       -      +
     92R  ASN*     4.9     3.8    +      -       -      +
     94R  ASP*     2.6    45.1    +      -       -      -
    108R  CYS*     3.3    26.4    -      -       -      -
    110R  PHE*     4.5     5.9    -      -       -      -
    124R  VAL*     4.1    10.8    -      -       +      -
    126R  TYR*     3.8    22.7    -      -       +      -
----------------------------------------------------------
 Back to top of page

Residues in contact with LYS 144 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    140Q  GLU*     3.0    49.0    +      -       +      +
    141Q  LYS*     4.1     3.1    -      -       -      +
    143Q  ARG*     1.3    78.4    -      -       +      +
    145Q  GLU*     1.3    63.1    +      -       +      +
    147Q  VAL*     3.3     4.9    +      -       -      +
    148Q  THR*     3.2    23.7    +      -       -      -
    124R  VAL*     4.1    14.6    -      -       +      +
    126R  TYR*     4.0    11.7    -      -       +      +
    149R  ASP*     2.7    34.8    +      -       -      -
    153R  ARG*     3.5    41.3    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with GLU 145 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    126Q  TYR      4.0     4.0    -      -       -      +
    127Q  GLY*     4.1     8.3    -      -       -      -
    128Q  VAL*     3.6    11.4    +      -       -      +
    141Q  LYS*     2.9    63.7    +      -       +      +
    144Q  LYS*     1.3    74.2    -      -       +      +
    146Q  ALA*     1.3    61.7    +      -       -      +
    148Q  THR*     4.0     5.1    -      -       -      +
    149Q  ASP*     2.7    34.8    +      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 146 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     91Q  GLN*     3.9     4.9    -      -       -      +
    107Q  VAL*     3.5    13.7    -      -       +      +
    109Q  ALA*     3.7    21.6    -      -       +      +
    125Q  GLY*     3.5     8.1    -      -       -      -
    126Q  TYR      3.6    13.9    -      -       -      -
    127Q  GLY*     3.5    12.7    -      -       -      +
    142Q  ALA      3.0    18.0    +      -       -      +
    143Q  ARG      3.6     5.2    -      -       -      +
    144Q  LYS      3.2     0.2    -      -       -      -
    145Q  GLU*     1.3    77.5    -      -       -      +
    147Q  VAL*     1.3    56.8    +      -       -      +
    150Q  GLY*     2.9    25.5    +      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with VAL 147 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     86Q  HIS*     5.1     6.5    -      -       +      +
     88Q  ILE*     3.9    29.2    -      -       +      -
     91Q  GLN*     3.6    11.4    -      -       -      +
    109Q  ALA*     4.0    11.4    -      -       +      -
    111Q  VAL*     3.7     6.3    -      -       +      +
    143Q  ARG      3.3     4.7    +      -       -      +
    144Q  LYS      3.3     6.7    +      -       -      +
    145Q  GLU      3.2     0.8    -      -       -      -
    146Q  ALA*     1.3    76.9    -      -       -      +
    148Q  THR*     1.3    59.3    +      -       -      +
    150Q  GLY*     3.0     2.4    +      -       -      -
    151Q  LEU*     2.8    28.7    +      -       +      +
    122R  GLU      4.6     3.8    -      -       -      +
    123R  ASP*     3.6    26.0    -      -       -      +
    124R  VAL*     3.3    28.3    -      -       +      -
----------------------------------------------------------
 Back to top of page

Residues in contact with THR 148 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     68Q  GLY*     4.0    27.4    -      -       -      +
     72Q  ILE*     6.5     1.1    -      -       +      -
    144Q  LYS      3.2    14.2    +      -       -      -
    145Q  GLU*     4.0     5.4    -      -       -      -
    147Q  VAL*     1.3    78.9    -      -       -      +
    149Q  ASP*     1.3    58.7    +      -       -      +
    151Q  LEU*     3.4    10.4    +      -       +      +
    152Q  LYS*     2.9    37.2    +      -       +      +
    123R  ASP*     5.1     3.3    +      -       -      -
    153R  ARG*     3.8    16.6    +      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with ASP 149 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    140P  GLU*     5.3     0.2    -      -       -      -
    144P  LYS*     2.6    34.9    +      -       -      -
    125Q  GLY*     3.4     2.3    -      -       -      -
    126Q  TYR      2.9    24.6    +      -       -      +
    145Q  GLU*     2.7    23.6    +      -       +      +
    146Q  ALA      3.7     3.6    -      -       -      +
    148Q  THR*     1.3    74.3    -      -       -      +
    150Q  GLY*     1.3    57.1    +      -       -      +
    152Q  LYS*     3.3    21.1    +      -       -      +
    153Q  ARG*     2.8    40.3    +      -       -      +
    156Q  ARG*     5.0     4.2    +      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with GLY 150 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    111Q  VAL*     3.8    16.2    -      -       -      +
    123Q  ASP*     4.5     2.5    -      -       -      +
    124Q  VAL      4.0     4.3    -      -       -      -
    125Q  GLY*     3.4    22.6    -      -       -      -
    146Q  ALA      2.9    12.0    +      -       -      -
    147Q  VAL      3.5     3.1    -      -       -      -
    149Q  ASP*     1.3    74.7    -      -       -      +
    151Q  LEU*     1.3    58.9    +      -       -      +
    153Q  ARG*     3.2     2.0    +      -       -      +
    154Q  ALA*     2.8    32.1    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with LEU 151 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     71Q  VAL*     5.6     0.9    -      -       +      -
     72Q  ILE*     4.4    20.0    -      -       +      -
     84Q  TRP*     3.8    17.3    -      -       +      -
     86Q  HIS*     3.8    49.1    -      -       +      +
    111Q  VAL*     3.8    14.1    -      -       +      +
    113Q  VAL*     4.7     5.2    -      -       +      -
    147Q  VAL*     2.8    20.1    +      -       +      +
    148Q  THR*     3.7     9.2    -      -       +      +
    150Q  GLY*     1.3    71.8    -      -       -      +
    152Q  LYS*     1.3    64.9    +      -       +      +
    154Q  ALA*     3.8     1.0    -      -       -      +
    155Q  LEU*     3.0    48.6    +      -       +      +
    123R  ASP*     6.2     0.2    -      -       -      +
    157R  SER*     5.2     0.4    -      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with LYS 152 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     65Q  TYR*     4.2    16.4    -      -       -      +
     66Q  ILE*     2.9    33.1    +      -       +      +
     67Q  GLU*     4.9     0.2    -      -       -      +
     68Q  GLY*     4.1    13.5    -      -       -      +
     71Q  VAL*     3.8    35.2    -      -       +      -
    148Q  THR*     2.9    31.0    +      -       +      +
    149Q  ASP*     3.6    20.6    +      -       -      +
    151Q  LEU*     1.3    79.0    -      -       +      +
    153Q  ARG*     1.3    64.5    +      -       -      +
    155Q  LEU*     3.3     2.3    +      -       -      +
    156Q  ARG*     3.1    44.3    +      -       -      +
    162Q  LEU      4.8     1.4    -      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ARG 153 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    144P  LYS*     3.4    56.6    +      -       -      +
    148P  THR*     3.8    18.0    +      -       -      -
    123Q  ASP*     2.4    57.9    +      -       +      +
    124Q  VAL*     2.9    22.0    +      -       -      +
    149Q  ASP*     2.8    29.0    +      -       -      +
    150Q  GLY      3.9     2.7    -      -       -      +
    152Q  LYS*     1.3    71.6    -      -       -      +
    154Q  ALA*     1.3    65.2    +      -       -      +
    156Q  ARG*     3.2    44.5    +      -       -      +
    157Q  SER*     3.9     4.9    +      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 154 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    111Q  VAL*     3.7    14.4    -      -       +      +
    113Q  VAL*     3.2    27.0    -      -       +      +
    121Q  HIS*     3.7    15.6    -      -       -      +
    122Q  GLU      4.8     1.3    -      -       -      -
    123Q  ASP*     3.8    11.8    -      -       -      +
    150Q  GLY      2.8    21.1    +      -       -      +
    151Q  LEU*     3.8     5.2    -      -       -      +
    153Q  ARG*     1.3    72.2    -      -       -      +
    155Q  LEU*     1.3    64.8    +      -       -      +
    157Q  SER*     3.1    25.1    +      -       -      -
    158Q  PHE*     4.5     1.2    +      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with LEU 155 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     71Q  VAL*     3.8    20.2    -      -       +      -
     72Q  ILE*     5.9     0.2    -      -       -      -
     75Q  ALA*     4.5     9.6    -      -       +      -
     79Q  PHE*     4.9     5.2    -      -       +      -
     84Q  TRP*     4.2    15.3    -      -       +      -
    113Q  VAL*     3.5    28.9    -      -       +      -
    151Q  LEU*     3.0    45.8    +      -       +      +
    152Q  LYS      3.7     4.0    -      -       -      +
    154Q  ALA*     1.3    75.0    -      -       -      +
    156Q  ARG*     1.3    65.2    +      -       -      +
    157Q  SER      2.9     1.4    +      -       -      -
    158Q  PHE*     2.9    34.9    +      -       +      +
    162Q  LEU*     3.6    32.9    -      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ARG 156 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     72P  ILE*     5.0     3.8    -      -       +      -
     65Q  TYR*     6.2     2.6    -      -       -      +
     66Q  ILE*     4.9     9.1    -      -       -      +
     71Q  VAL*     6.1     1.0    -      -       -      +
    149Q  ASP*     5.0     4.8    +      -       -      -
    152Q  LYS*     3.1    38.5    +      -       -      +
    153Q  ARG*     3.4    37.9    -      -       -      +
    154Q  ALA      3.2     0.6    -      -       -      -
    155Q  LEU*     1.3    75.6    -      -       -      +
    157Q  SER*     1.3    63.0    +      -       -      +
    158Q  PHE      3.0     1.9    +      -       -      -
    159Q  GLY      3.0    11.8    +      -       -      +
    162Q  LEU      3.8    12.2    +      -       -      +
    163Q  GLY*     3.7    23.8    +      -       -      +
    164Q  ASN*     3.4    30.3    -      -       -      +
    166Q  ILE*     3.9    25.6    -      -       -      +
    167Q  LEU*     4.2    15.3    -      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with SER 157 (chain Q). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     72P  ILE*     3.4    22.9    -      -       -      +
     76P  ASN*     2.9    24.9    +      -       -      +
     84P  TRP*     3.8     9.2    -      -       -      -
     86P  HIS*     3.5    18.3    -      -       -      -
    151P  LEU*     5.2     0.9    -      -       -      +
    121Q  HIS*     3.3    29.1    -      -       -      -
    123Q  ASP*     5.2     2.4    +      -       -      -
    153Q  ARG      4.0     5.4    +      -       -      -
    154Q  ALA*     3.1    16.4    +      -       -      -
    155Q  LEU      2.9     1.2    +      -       -      -
    156Q  ARG*     1.3    78.7    -      -       -      +
    158Q  PHE*     1.3    58.0    +      -       -      +
    159Q  GLY      3.3     0.2    -      -       -      -
----------------------------------------------------------
 Back to top of page


A short description of the analytical approach
The contact analysis used in this page is based upon the approach developed in: Sobolev V., Wade R.C., Vriend G. and Edelman M. PROTEINS (1996) 25, 120-129. Contact legitimacy depends on the hydrophobic-hydrophilic properties of the contacting atoms. In order to define it, for each inter-atomic contact, eight atom classes have been introduced:


   I  Hydrophilic      - N and O that can donate and accept hydrogen bonds
                         (e.g., oxygen of hydroxyl group of Ser. or Thr)
  II  Acceptor         - N or O that can only accept a hydrogen bond
 III  Donor            - N that can only donate a hydrogen bond
  IV  Hydrophobic      - Cl, Br, I and all C atoms that are not in
                         aromatic rings and do not have a covalent bond to
                         a N or O atom
   V  Aromatic         - C in aromatic rings irrespective of any other 
                         bonds formed by the atom
  VI  Neutral          - C atoms that have a covalent bond to at least one
                         atom of class I or two or more atoms from class II
                         or III; atoms; S, F, P, and metal atoms in all cases
 VII  Neutral-donor    - C atoms that have a covalent bond with only one
                         atom of class III
VIII  Neutral-acceptor - C atoms that have a covalent bond with only 
                         one atom of class II
For each pair of contacts the state of legitimacy is shown below:

Legend:
+, legitimate
-, illegitimate
------------------------------------------------------------
  Atomic class           I  II  III   IV   V   VI  VII  VIII
------------------------------------------------------------
   I  (Hydrophilic)      +   +    +    -   +   +    +    +
  II  (Acceptor)         +   -    +    -   +   +    +    -
 III  (Donor)            +   +    -    -   +   +    -    +
  IV  (Hydrophobic)      -   -    -    +   +   +    +    +
   V  (Aromatic)         +   +    +    +   +   +    +    +
  VI  (Neutral)          +   +    +    +   +   +    +    +
 VII  (Neutral-donor)    +   +    -    +   +   +    -    +
VIII  (Neutral-acceptor) +   -    +    +   +   +    +    -
------------------------------------------------------------
Warning!
Atom classes for heterogroups are automatically assigned based on the atomic coordinates. However, in three cases (see below) the automatic assignment is currently ambiguous. In these cases, the user is advised to manually analyse the full list of contacts using LPC software.
1. Carbon atoms belonging to a 4-, 5- or 6-member ring are 
   considered "aromatic" (Class V) if the ring is approximately
   planar, and "hydrophobic" (Class IV) or "neutral" (Classes
   VI, VII, VIII) if the ring is non-planar.
2. The oxygen atom of a carbonyl or hydroxy group is considered
   "hydroxy" (Class I) if the CO bond is longer than 1.29 Å, and
   "carbonyl" (Class II) if shorter.
3. All nitrogen atoms are considered "hydrophilic" (Class I).

Please E-mail any questions and/or suggestions concerning this page to Vladimir.Sobolev@weizmann.ac.il