Contacts of the helix formed by residues 114 - 141 (chain A) in PDB entry 2IAI


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 THR 114 (chain A).
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     27A  TYR*     4.5    15.5    +      -       -      -
     54A  GLU*     3.8    24.7    +      -       -      +
     57A  LEU*     5.0     1.0    -      -       -      -
    113A  ASN*     3.8    20.1    +      -       -      +
    115A  GLY*     1.3    65.7    +      -       -      +
    116A  THR*     3.7     4.9    -      -       -      -
    117A  GLU*     2.8    44.0    +      -       -      -
    118A  ARG*     2.9    38.3    -      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with GLY 115 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     54A  GLU*     3.8     5.2    +      -       -      -
    114A  THR*     1.3    74.2    +      -       -      +
    116A  THR*     1.3    56.5    +      -       -      +
    118A  ARG*     3.4    20.7    +      -       -      +
    119A  TRP*     2.9    30.7    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with THR 116 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     54A  GLU*     2.6    37.4    +      -       -      +
     57A  LEU*     4.3    12.3    -      -       +      -
     58A  ARG*     3.6    51.4    -      -       +      +
     61A  VAL*     4.3     9.4    -      -       +      -
    114A  THR*     3.2     1.5    -      -       -      +
    115A  GLY*     1.3    77.5    -      -       -      +
    117A  GLU*     1.3    57.9    +      -       -      +
    119A  TRP*     3.3    10.1    +      -       +      +
    120A  ALA*     2.9    27.7    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with GLU 117 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     27A  TYR*     4.1    17.8    -      -       -      +
     28A  ASP*     4.5     6.9    -      -       -      +
     57A  LEU*     3.8    22.5    -      -       +      +
    110A  VAL*     3.4    24.4    -      -       +      +
    111A  ARG      3.9     6.8    +      -       -      -
    112A  GLY*     3.3    39.2    +      -       -      +
    113A  ASN      3.8     1.0    +      -       -      -
    114A  THR*     2.8    36.7    +      -       -      +
    116A  THR*     1.3    71.3    -      -       -      +
    118A  ARG*     1.3    60.9    +      -       -      +
    120A  ALA*     3.3     3.1    +      -       -      +
    121A  LEU*     2.9    35.8    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ARG 118 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    112A  GLY      4.1    12.6    -      -       -      +
    113A  ASN*     3.1    52.8    -      -       +      +
    114A  THR*     2.9    19.1    -      -       -      +
    115A  GLY*     3.6    24.5    -      -       -      +
    117A  GLU*     1.3    75.7    -      -       -      +
    119A  TRP*     1.3    58.5    +      -       -      +
    121A  LEU*     3.3    10.2    +      -       +      +
    122A  GLU*     2.9    39.8    +      -       -      +
    125A  ARG*     4.8     0.5    +      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with TRP 119 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     58A  ARG*     4.5    20.0    -      -       +      -
     61A  VAL*     4.3    13.9    -      -       +      -
     62A  SER*     4.1    23.3    -      -       -      -
     65A  LEU*     4.1    20.6    -      -       +      -
     66A  ASP*     6.1     0.9    -      -       -      -
    115A  GLY      2.9    18.0    +      -       -      +
    116A  THR*     3.5    10.8    -      -       +      +
    117A  GLU      3.2     0.2    -      -       -      -
    118A  ARG*     1.3    76.9    -      -       -      +
    120A  ALA*     1.3    68.4    +      -       +      +
    122A  GLU*     3.2    20.9    +      -       -      +
    123A  ARG*     2.9    59.8    +      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 120 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     61A  VAL*     4.0    24.5    -      -       +      -
     65A  LEU*     4.1     6.7    -      -       +      -
    107A  LEU*     4.1    17.8    -      -       +      +
    110A  VAL*     4.6     9.4    -      -       +      -
    116A  THR      2.9    16.1    +      -       -      +
    117A  GLU*     3.3     8.0    +      -       -      +
    119A  TRP*     1.3    80.6    -      -       +      +
    121A  LEU*     1.3    57.6    +      -       -      +
    123A  ARG*     3.3     2.8    +      -       -      +
    124A  ARG*     2.9    32.3    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with LEU 121 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    110A  VAL*     3.6    33.4    -      -       +      +
    111A  ARG*     5.1     1.8    -      -       -      -
    112A  GLY      4.0    21.1    -      -       -      +
    117A  GLU      2.9    22.7    +      -       -      +
    118A  ARG*     3.7     9.0    -      -       +      +
    119A  TRP      3.2     0.2    -      -       -      -
    120A  ALA*     1.3    73.9    -      -       -      +
    122A  GLU*     1.3    64.0    +      -       -      +
    124A  ARG*     3.3    22.3    +      -       +      +
    125A  ARG*     3.0    46.3    +      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with GLU 122 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    118A  ARG*     2.9    25.1    +      -       +      +
    119A  TRP*     3.2    25.0    +      -       -      +
    121A  LEU*     1.3    73.1    -      -       -      +
    123A  ARG*     1.3    67.4    +      -       +      +
    125A  ARG*     3.1    31.6    +      -       -      +
    126A  GLU*     2.9    22.6    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ARG 123 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     65A  LEU*     3.8    21.3    -      -       +      +
     69A  PHE*     3.2    60.5    -      -       +      +
    119A  TRP*     2.9    58.5    +      -       +      +
    120A  ALA      3.6     4.3    -      -       -      +
    122A  GLU*     1.3    77.1    -      -       -      +
    124A  ARG*     1.3    59.9    +      -       -      +
    126A  GLU*     3.2    16.2    +      -       -      +
    127A  PHE      3.0    22.3    +      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with ARG 124 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     65A  LEU*     4.2     3.4    -      -       +      -
     68A  LEU*     6.0     0.9    -      -       +      -
    107A  LEU*     3.8    42.9    +      -       +      +
    108A  LEU*     3.3    45.9    +      -       -      +
    110A  VAL*     5.6     1.2    +      -       -      -
    120A  ALA      2.9    18.0    +      -       -      +
    121A  LEU*     3.7    22.7    -      -       +      +
    122A  GLU      3.3     0.2    -      -       -      -
    123A  ARG*     1.3    76.3    -      -       -      +
    125A  ARG*     1.3    58.4    +      -       +      +
    127A  PHE*     3.4     8.8    +      -       -      +
    128A  ASP*     2.9    27.9    +      -       -      +
    155A  ARG*     5.9     3.0    -      -       -      +
    158A  PHE*     5.8     4.0    -      -       -      -
    162A  ASN*     3.9    12.9    -      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ARG 125 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    118A  ARG      5.0     0.2    +      -       -      -
    121A  LEU*     3.0    39.9    +      -       +      +
    122A  GLU*     3.1    42.1    +      -       -      +
    124A  ARG*     1.3    75.4    -      -       +      +
    126A  GLU*     1.3    61.4    +      -       -      +
    128A  ASP*     3.4     9.8    +      -       -      +
    129A  HIS*     2.9    44.6    +      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with GLU 126 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     69A  PHE*     4.0    17.5    -      -       +      -
    122A  GLU      2.9    12.7    +      -       -      +
    123A  ARG*     3.2    23.3    +      -       -      +
    125A  ARG*     1.3    73.2    -      -       -      +
    127A  PHE*     1.3    65.3    +      -       -      +
    129A  HIS*     3.2    18.1    +      -       -      +
    130A  ARG*     3.0    44.2    +      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with PHE 127 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     65A  LEU*     5.8     1.1    -      -       +      -
     68A  LEU*     3.3    51.4    -      -       +      -
     69A  PHE*     3.6    21.7    -      +       +      -
     71A  ILE*     5.1     0.7    -      -       +      -
     72A  LEU*     3.8    29.4    -      -       +      -
     89A  VAL*     5.0     0.2    -      -       +      -
     93A  MSE      4.0    29.6    -      -       +      -
    123A  ARG      3.0    13.1    +      -       -      +
    124A  ARG*     3.6    12.3    -      -       -      +
    126A  GLU*     1.3    75.1    -      -       -      +
    128A  ASP*     1.3    65.9    +      -       -      +
    130A  ARG*     3.1     6.1    +      -       -      +
    131A  VAL*     3.0    31.1    +      -       +      +
    158A  PHE*     3.8    30.3    -      +       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with ASP 128 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    124A  ARG      2.9    15.7    +      -       -      +
    125A  ARG*     3.5    13.1    -      -       -      +
    127A  PHE*     1.3    77.8    -      -       -      +
    129A  HIS*     1.3    66.0    +      -       -      +
    131A  VAL*     3.1     2.4    +      -       -      +
    132A  ALA*     2.9    29.1    +      -       -      +
    151A  ARG*     4.9     5.7    +      -       -      +
    154A  THR*     3.6    21.0    -      -       -      +
    155A  ARG*     3.4    40.7    +      -       -      +
    158A  PHE*     4.0    18.3    -      -       +      -
----------------------------------------------------------
 Back to top of page

Residues in contact with HIS 129 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    125A  ARG*     2.9    35.3    +      -       +      +
    126A  GLU*     3.2    23.3    +      -       -      +
    128A  ASP*     1.3    81.1    +      -       -      +
    130A  ARG*     1.3    57.2    +      -       -      +
    132A  ALA*     3.4     7.2    +      -       -      +
    133A  ALA*     3.0    28.4    +      -       -      +
    151A  ARG*     3.1    34.2    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ARG 130 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     69A  PHE*     4.4    19.2    +      -       -      -
     72A  LEU*     3.7    50.3    +      -       +      +
     73A  ASP*     4.0    24.9    +      -       -      -
     78A  ARG*     5.2     3.8    -      -       -      +
    126A  GLU*     3.0    35.7    +      -       -      +
    127A  PHE      3.1     7.8    +      -       -      +
    129A  HIS*     1.3    76.7    -      -       -      +
    131A  VAL*     1.3    63.8    +      -       -      +
    133A  ALA*     3.1    16.0    +      -       -      +
    134A  LEU*     3.1    17.6    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with VAL 131 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     72A  LEU*     4.2     8.3    -      -       +      -
     86A  LEU*     3.9    21.5    -      -       +      -
     89A  VAL*     4.2    19.5    -      -       +      -
     90A  VAL*     5.9     1.8    -      -       +      -
     93A  MSE      4.6     1.1    -      -       -      -
    127A  PHE*     3.0    32.4    +      -       +      +
    128A  ASP      3.9     1.3    -      -       -      +
    130A  ARG*     1.3    76.4    -      -       -      +
    132A  ALA*     1.3    61.7    +      -       -      +
    134A  LEU*     3.0    17.4    +      -       +      +
    135A  LEU*     3.1    12.7    +      -       +      +
    154A  THR*     4.5     5.4    -      -       +      +
    158A  PHE*     3.6    39.0    -      -       +      -
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 132 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    128A  ASP*     2.9    19.8    +      -       -      +
    129A  HIS*     3.6     5.2    -      -       -      +
    131A  VAL*     1.3    76.5    -      -       -      +
    133A  ALA*     1.3    57.1    +      -       -      +
    135A  LEU      3.2     0.7    +      -       -      -
    136A  LYS*     2.9    25.0    +      -       -      +
    150A  VAL*     3.4    11.9    -      -       +      +
    151A  ARG*     4.0    32.5    -      -       +      +
    154A  THR*     3.6    27.7    -      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 133 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    129A  HIS      3.0    13.4    +      -       -      +
    130A  ARG*     3.1    12.1    +      -       -      +
    132A  ALA*     1.3    75.3    -      -       -      +
    134A  LEU*     1.3    60.8    +      -       +      +
    136A  LYS*     3.3     9.6    +      -       +      +
    137A  ASP*     2.9    39.8    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with LEU 134 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     72A  LEU*     4.7     7.6    -      -       +      -
     77A  ALA*     4.7     9.0    -      -       +      +
     82A  ALA*     4.1     7.6    -      -       +      +
     85A  ARG*     4.6    22.7    -      -       +      +
     86A  LEU*     4.2    22.0    -      -       +      -
     89A  VAL*     3.8    34.3    -      -       +      -
    130A  ARG      3.1    15.5    +      -       -      +
    131A  VAL*     3.0    16.0    +      -       -      +
    133A  ALA*     1.3    78.1    -      -       +      +
    135A  LEU*     1.3    61.6    +      -       -      +
    137A  ASP*     3.2    14.0    +      -       +      +
    138A  ALA*     2.9    22.3    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with LEU 135 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     86A  LEU*     4.0    30.7    -      -       +      +
    131A  VAL*     3.1    12.1    +      -       +      +
    132A  ALA      3.2     7.6    +      -       -      +
    134A  LEU*     1.3    75.7    -      -       -      +
    136A  LYS*     1.3    57.4    +      -       -      +
    138A  ALA*     3.2     3.4    +      -       -      +
    139A  ALA*     2.9    26.0    +      -       -      +
    144A  VAL*     3.9    22.3    -      -       +      +
    148A  VAL      5.9     0.4    -      -       -      +
    150A  VAL*     3.8    29.8    -      -       +      -
    153A  ALA*     4.2    12.8    -      -       +      -
    154A  THR*     3.5    32.3    -      -       +      +
    157A  VAL*     5.4     7.9    -      -       +      -
----------------------------------------------------------
 Back to top of page

Residues in contact with LYS 136 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    132A  ALA      2.9    17.6    +      -       -      +
    133A  ALA*     3.5    10.3    -      -       +      +
    135A  LEU*     1.3    76.3    -      -       -      +
    137A  ASP*     1.3    59.0    +      -       -      +
    139A  ALA*     3.2     4.3    +      -       +      +
    140A  ALA*     3.0    28.8    +      -       +      +
    150A  VAL*     3.8    25.4    -      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ASP 137 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     82A  ALA*     3.6    15.7    -      -       +      +
    133A  ALA*     2.9    23.5    +      -       -      +
    134A  LEU*     3.2    17.0    +      -       +      +
    136A  LYS*     1.3    78.8    -      -       -      +
    138A  ALA*     1.3    65.1    +      -       -      +
    140A  ALA*     3.2     8.1    +      -       -      +
    141A  GLU*     3.0    31.6    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 138 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     82A  ALA*     3.3     8.7    -      -       -      +
     83A  ALA*     3.9    26.9    -      -       +      +
     86A  LEU*     4.7     2.5    -      -       +      -
    134A  LEU      2.9    13.7    +      -       -      +
    135A  LEU*     3.2     7.4    +      -       -      +
    137A  ASP*     1.3    78.1    -      -       -      +
    139A  ALA*     1.3    57.8    +      -       -      +
    141A  GLU*     3.4     3.4    +      -       -      +
    142A  GLY      3.3     3.6    +      -       -      -
    143A  ASP*     3.0    28.0    +      -       -      +
    144A  VAL*     3.2    26.6    +      -       +      -
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 139 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    135A  LEU      2.9    12.7    +      -       -      +
    136A  LYS*     3.5    11.4    -      -       +      +
    138A  ALA*     1.3    74.5    -      -       -      +
    140A  ALA*     1.3    64.5    +      -       -      +
    142A  GLY*     3.1    14.6    +      -       -      -
    144A  VAL*     3.5    29.8    -      -       +      +
    145A  ARG      4.5     5.8    -      -       -      +
    146A  ALA*     5.6     4.7    -      -       +      +
    150A  VAL*     4.6    11.0    -      -       +      -
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 140 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    136A  LYS*     3.0    14.3    +      -       +      +
    137A  ASP*     3.2    12.1    +      -       -      +
    139A  ALA*     1.3    79.6    -      -       -      +
    141A  GLU*     1.3    60.2    +      -       +      +
    142A  GLY*     3.2     1.7    +      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with GLU 141 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     81A  THR*     3.8    12.9    -      -       -      +
     82A  ALA*     2.9    42.9    +      -       -      +
     83A  ALA      4.5     0.2    +      -       -      -
    137A  ASP*     3.0    17.9    +      -       -      +
    138A  ALA*     3.9     6.1    -      -       -      +
    139A  ALA      3.2     0.2    -      -       -      -
    140A  ALA*     1.3    77.0    -      -       +      +
    142A  GLY*     1.3    60.6    +      -       -      +
    143A  ASP*     3.3    15.4    +      -       -      +
----------------------------------------------------------
 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