Contacts of the helix formed by residues 117 - 141 (chain A) in PDB entry 3NX4


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 117 (chain A).
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    112A  LEU*     4.2     1.6    -      -       -      -
    115A  GLY      4.1     1.8    +      -       -      -
    116A  LEU*     1.3    78.6    -      -       -      +
    118A  SER*     1.3    64.2    +      -       -      +
    119A  ARG*     3.5     8.1    +      -       -      +
    120A  ASN*     2.9    36.7    +      -       -      +
    121A  ALA*     2.9    22.3    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with SER 118 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     35A  HIS*     4.7     3.6    +      -       -      +
     36A  TRP*     3.5    18.5    -      -       -      -
     66A  ALA*     3.4    31.5    -      -       -      +
     67A  GLY*     4.1     2.9    +      -       -      -
     82A  GLU*     3.9    20.3    +      -       -      -
     83A  VAL      5.2     0.6    +      -       -      -
    112A  LEU*     3.8    19.7    -      -       -      +
    117A  SER*     1.3    72.8    -      -       -      +
    119A  ARG*     1.3    62.7    +      -       -      +
    121A  ALA*     3.3    14.8    +      -       -      +
    122A  MSE      3.5     5.0    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ARG 119 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     36A  TRP*     3.5    40.2    -      -       +      +
    117A  SER*     3.2     7.3    +      -       -      +
    118A  SER*     1.3    78.7    -      -       -      +
    120A  ASN*     1.3    66.0    +      -       -      +
    122A  MSE      3.2     5.9    +      -       -      +
    123A  ILE*     3.1    38.9    +      -       +      +
    291A  TYR*     5.3     3.0    +      -       -      +
    295A  ALA*     5.1     5.5    -      -       -      +
    297A  GLU*     2.9    37.2    +      -       -      +
    320A  LEU*     3.5    23.4    -      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ASN 120 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    116A  LEU*     3.9    11.4    -      -       +      +
    117A  SER*     2.9    27.0    +      -       -      +
    119A  ARG*     1.3    80.6    +      -       -      +
    121A  ALA*     1.3    65.2    +      -       -      +
    123A  ILE*     3.3    18.2    +      -       -      +
    124A  ILE*     3.1    27.4    +      -       -      +
    288A  GLU*     4.7     8.5    +      -       -      -
    291A  TYR*     3.5    47.0    -      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 121 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     66A  ALA*     4.6     1.1    -      -       +      -
     84A  LEU*     3.8    29.4    -      -       +      -
    112A  LEU*     3.9     7.9    -      -       +      -
    116A  LEU*     3.8    17.6    -      -       +      +
    117A  SER      2.9    13.6    +      -       -      +
    118A  SER      3.4    11.2    -      -       -      +
    119A  ARG      3.2     0.2    -      -       -      -
    120A  ASN*     1.3    75.8    -      -       -      +
    122A  MSE      1.3    70.8    +      -       +      +
    124A  ILE*     3.5     4.8    -      -       -      +
    125A  GLY      2.9    19.9    +      -       -      -
    279A  TRP*     3.6     6.6    -      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with MSE 122 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     36A  TRP*     3.6    26.7    -      -       +      +
     37A  SER*     3.7    11.2    -      -       -      +
     38A  SER*     3.4     7.8    -      -       -      -
     64A  ASP*     3.5    28.0    -      -       +      +
     65A  PHE*     3.4    34.1    -      -       -      +
     66A  ALA*     3.7    15.5    -      -       +      -
     84A  LEU*     4.3    10.3    -      -       +      -
     85A  LEU      4.1     7.4    -      -       -      +
     86A  THR*     4.4     9.0    -      -       +      -
    118A  SER      3.5     0.4    +      -       -      +
    119A  ARG      3.2     4.3    +      -       -      +
    120A  ASN      3.1     0.4    -      -       -      -
    121A  ALA*     1.3    98.4    -      -       +      +
    123A  ILE*     1.3    66.4    +      -       -      +
    124A  ILE      3.1     0.9    -      -       -      -
    125A  GLY*     3.4     3.2    +      -       -      +
    279A  TRP*     5.0     1.1    -      -       +      -
    318A  ARG*     3.0    20.3    +      -       -      -
    319A  THR      5.1     0.2    -      -       -      +
    320A  LEU*     3.6    22.4    -      -       +      -
----------------------------------------------------------
 Back to top of page

Residues in contact with ILE 123 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    119A  ARG*     3.1    33.1    +      -       -      +
    120A  ASN*     3.3    28.7    +      -       -      +
    122A  MSE      1.3    75.1    -      -       -      +
    124A  ILE*     1.3    53.9    +      -       -      +
    290A  PHE*     4.3    12.1    -      -       +      -
    291A  TYR*     3.8    30.3    -      -       +      +
    294A  ALA*     4.9     0.4    -      -       +      -
    295A  ALA*     3.6    36.1    -      -       +      +
    318A  ARG*     2.7    43.0    +      -       +      +
    319A  THR      6.3     0.2    -      -       -      -
    320A  LEU*     3.9    16.8    -      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ILE 124 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    116A  LEU*     4.0    12.8    -      -       +      -
    120A  ASN      3.1    15.6    +      -       -      +
    121A  ALA      3.5     5.6    -      -       -      +
    122A  MSE      3.8     0.2    -      -       -      -
    123A  ILE*     1.3    75.0    -      -       -      +
    125A  GLY*     1.3    60.7    +      -       -      +
    128A  GLY*     2.8    32.3    +      -       -      -
    129A  PHE      3.5    23.6    -      -       -      +
    162A  THR*     5.6     0.4    -      -       -      -
    279A  TRP*     3.7    20.4    -      -       +      -
    282A  LEU*     3.7    26.5    -      -       +      -
    286A  LEU*     3.8    22.4    -      -       +      -
    290A  PHE*     5.2     3.8    -      -       +      -
    291A  TYR*     3.8    22.0    -      -       +      +
    318A  ARG*     3.2    13.2    +      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with GLY 125 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     64A  ASP*     3.4    14.6    -      -       -      -
     86A  THR*     4.0    11.9    -      -       -      -
    121A  ALA      2.9    20.3    +      -       -      -
    122A  MSE      3.4     7.9    +      -       -      -
    124A  ILE*     1.3    81.1    -      -       -      +
    126A  THR*     1.3    62.7    +      -       -      -
    129A  PHE*     3.0    19.4    +      -       -      +
    279A  TRP*     4.3     1.1    -      -       -      -
    318A  ARG*     3.6     8.3    -      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with THR 126 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     40A  ASN*     3.5    10.3    +      -       -      +
     42A  LYS*     6.3     0.2    -      -       -      -
     63A  ILE*     3.5    24.1    -      -       +      +
     64A  ASP*     2.5    33.5    +      -       -      -
     86A  THR*     3.5    12.1    -      -       -      -
     87A  GLY*     4.3     4.0    +      -       -      -
    125A  GLY*     1.3    71.5    -      -       -      -
    127A  ALA*     1.3    54.5    -      -       -      +
    129A  PHE*     3.8     5.9    -      -       -      +
    130A  THR*     2.7    37.4    +      -       -      -
    267A  SER*     3.6    24.5    -      -       -      +
    330A  NAP      3.6    19.1    -      -       +      -
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 127 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     40A  ASN*     3.0    16.9    +      -       -      +
    125A  GLY      3.2     0.8    -      -       -      -
    126A  THR*     1.3    77.9    -      -       -      +
    128A  GLY*     1.3    58.7    +      -       -      +
    130A  THR      3.4     0.3    +      -       -      -
    131A  ALA*     3.0    22.0    +      -       -      +
    158A  GLY*     3.6    28.0    -      -       -      -
    159A  VAL*     3.4    28.4    -      -       +      +
    162A  THR*     4.6     0.2    -      -       -      -
    318A  ARG*     3.6    20.0    -      -       -      +
    330A  NAP      4.3     6.7    -      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with GLY 128 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    124A  ILE*     2.8    34.5    +      -       -      -
    127A  ALA*     1.3    71.5    -      -       -      +
    129A  PHE*     1.3    66.2    +      -       -      +
    131A  ALA*     3.2     2.8    +      -       -      +
    132A  MSE      3.0    22.9    +      -       -      +
    162A  THR*     3.6    26.1    +      -       -      -
    282A  LEU*     3.7     5.5    -      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with PHE 129 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     86A  THR*     4.1    11.2    -      -       -      +
    124A  ILE*     3.5     2.4    -      -       -      +
    125A  GLY      3.0    18.7    +      -       -      +
    126A  THR*     3.8     4.9    -      -       -      +
    128A  GLY*     1.3    74.8    -      -       -      +
    130A  THR*     1.3    58.8    +      -       -      +
    132A  MSE      3.2     5.0    +      -       -      +
    133A  LEU*     3.0    51.8    +      -       +      +
    267A  SER*     3.7    29.2    -      -       -      -
    270A  THR*     3.7     7.2    -      -       +      -
    275A  ARG*     3.7    38.6    -      -       +      -
    278A  ALA*     3.7    24.7    -      -       +      -
    279A  TRP*     3.5    39.7    -      +       +      -
    282A  LEU*     4.0     8.3    -      -       +      -
----------------------------------------------------------
 Back to top of page

Residues in contact with THR 130 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    126A  THR      2.7    22.5    +      -       -      -
    127A  ALA      3.4     4.9    -      -       -      -
    129A  PHE*     1.3    73.7    -      -       -      +
    131A  ALA*     1.3    66.1    +      -       -      +
    133A  LEU*     3.2    12.0    +      -       -      +
    134A  CYS*     2.9    21.3    +      -       -      -
    159A  VAL*     4.2     2.5    -      -       +      -
    240A  CYS*     3.7    37.7    -      -       +      -
    265A  VAL*     4.3     9.2    -      -       +      -
    267A  SER*     3.2    11.5    -      -       -      -
    330A  NAP      3.1    33.2    -      -       +      -
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 131 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    127A  ALA      3.0    11.1    +      -       -      +
    128A  GLY      3.2     8.2    +      -       -      +
    130A  THR*     1.3    75.0    -      -       -      +
    132A  MSE      1.3    57.8    +      -       -      +
    134A  CYS*     3.1     7.3    +      -       -      +
    135A  VAL*     2.9    32.4    +      -       -      +
    159A  VAL*     3.5    32.3    -      -       +      +
    162A  THR*     3.7    12.1    -      -       +      -
    163A  ALA*     3.7    19.7    -      -       +      +
    166A  LEU*     4.2     2.2    -      -       +      -
    216A  ILE*     4.5     0.3    -      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with MSE 132 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    128A  GLY      3.0    13.1    +      -       -      +
    129A  PHE      3.4     8.5    -      -       -      +
    130A  THR      3.1     0.2    -      -       -      -
    131A  ALA*     1.3    74.0    -      -       -      +
    133A  LEU*     1.3    65.2    +      -       -      +
    135A  VAL*     3.3    16.2    +      -       +      -
    136A  MSE      2.9    38.7    +      -       +      +
    166A  LEU*     3.9    29.1    -      -       +      +
    170A  LEU*     5.2     0.2    -      -       +      -
    278A  ALA*     3.6    31.2    -      -       +      +
    281A  ARG*     3.6    50.7    -      -       +      +
    282A  LEU*     3.8    21.5    -      -       +      -
    285A  ASP*     4.3     1.8    -      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with LEU 133 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    129A  PHE*     3.0    44.4    +      -       +      +
    130A  THR*     3.2     6.9    +      -       -      +
    132A  MSE      1.3    75.9    -      -       -      +
    134A  CYS*     1.3    58.6    -      -       -      +
    136A  MSE      3.4     8.4    +      -       -      +
    137A  ALA*     3.0    26.0    +      -       -      +
    265A  VAL*     3.7    18.6    -      -       +      +
    266A  ASP      3.9    11.7    -      -       -      +
    267A  SER*     4.1     6.3    -      -       -      -
    270A  THR*     3.6    22.0    -      -       +      +
    274A  ARG*     4.1    35.3    +      -       +      +
    278A  ALA*     4.1    17.9    -      -       +      -
----------------------------------------------------------
 Back to top of page

Residues in contact with CYS 134 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    130A  THR      2.9    18.3    +      -       -      -
    131A  ALA*     3.1     8.7    +      -       -      +
    133A  LEU*     1.3    72.7    -      -       -      +
    135A  VAL*     1.3    67.8    +      -       -      +
    137A  ALA*     3.2     4.7    +      -       -      +
    138A  LEU*     3.1    24.1    +      -       -      +
    159A  VAL*     5.2     0.2    -      -       -      -
    216A  ILE*     3.8    31.0    -      -       +      -
    238A  ALA*     3.7    21.2    -      -       +      +
    240A  CYS*     4.0    25.1    -      -       -      -
    265A  VAL*     3.9    20.6    -      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with VAL 135 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    131A  ALA      2.9    18.3    +      -       -      +
    132A  MSE      3.3    20.6    +      -       +      +
    134A  CYS*     1.3    76.4    -      -       -      +
    136A  MSE      1.3    63.1    +      -       -      +
    138A  LEU*     3.2     9.8    +      -       +      +
    139A  GLU*     3.0    31.0    +      -       +      +
    163A  ALA*     4.8     1.6    -      -       -      +
    166A  LEU*     4.1    22.0    -      -       +      -
    167A  LEU*     4.1    18.2    -      -       +      -
    170A  LEU*     3.7    27.6    -      -       +      -
    172A  TYR*     5.6     2.0    -      -       +      -
    216A  ILE*     3.8    18.6    -      -       +      -
----------------------------------------------------------
 Back to top of page

Residues in contact with MSE 136 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    132A  MSE      2.9    37.6    +      -       +      +
    133A  LEU*     3.7     7.0    -      -       -      +
    134A  CYS      3.2     0.2    -      -       -      -
    135A  VAL*     1.3    75.7    -      -       -      +
    137A  ALA*     1.3    57.7    +      -       -      +
    139A  GLU*     3.3    16.8    +      -       -      +
    140A  ASP*     2.8    34.1    +      -       -      +
    274A  ARG*     3.6    42.6    -      -       +      +
    277A  GLU*     3.5    40.6    -      -       +      +
    278A  ALA*     3.9    30.1    -      -       -      -
    281A  ARG*     4.2     7.4    -      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 137 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    133A  LEU      3.0    14.0    +      -       -      +
    134A  CYS*     3.2     9.8    +      -       -      +
    136A  MSE      1.3    73.6    -      -       -      +
    138A  LEU*     1.3    66.3    +      -       -      +
    140A  ASP*     3.2    13.9    +      -       -      +
    141A  ALA*     3.0    21.8    +      -       -      +
    236A  CYS*     4.3     4.1    -      -       -      -
    238A  ALA*     4.1    12.8    -      -       +      -
    261A  ARG*     4.8     1.4    +      -       -      -
    263A  GLN*     3.9    29.1    -      -       +      +
    265A  VAL*     4.5     3.6    -      -       +      -
    274A  ARG*     4.1     2.8    -      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with LEU 138 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    134A  CYS      3.1    12.8    +      -       -      +
    135A  VAL*     3.5     8.1    -      -       +      +
    137A  ALA*     1.3    75.0    -      -       -      +
    139A  GLU*     1.3    63.6    +      -       +      +
    141A  ALA*     3.0    11.0    +      -       -      +
    143A  ILE*     3.0    36.3    +      -       +      +
    150A  VAL*     3.9    34.3    -      -       +      -
    167A  LEU*     4.4    10.8    -      -       +      -
    172A  TYR*     5.3     3.6    -      -       +      +
    214A  GLY*     4.2     4.0    -      -       -      -
    215A  ALA      3.8    14.1    -      -       -      +
    216A  ILE*     4.0    18.2    -      -       +      -
    236A  CYS*     3.3    38.8    -      -       +      +
    238A  ALA*     4.3     4.5    -      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with GLU 139 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    135A  VAL*     3.0    26.6    +      -       +      +
    136A  MSE      3.4    15.1    -      -       -      +
    138A  LEU*     1.3    73.5    -      -       +      +
    140A  ASP*     1.3    61.7    +      -       -      +
    142A  GLY*     2.9    21.0    +      -       -      +
    143A  ILE      4.6     5.6    -      -       -      +
    170A  LEU*     4.2     7.1    -      -       -      +
    172A  TYR*     4.3    16.4    +      -       -      +
    281A  ARG*     2.8    45.6    +      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with ASP 140 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    136A  MSE      2.8    20.1    +      -       -      +
    137A  ALA*     3.4    12.4    -      -       -      +
    139A  GLU*     1.3    73.3    -      -       -      +
    141A  ALA*     1.3    60.6    +      -       -      +
    142A  GLY*     3.2     1.1    +      -       -      -
    261A  ARG*     3.9    14.5    +      -       -      +
    274A  ARG*     2.9    31.6    +      -       -      -
    261B  ARG*     4.8    10.6    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 141 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    137A  ALA      3.0    10.9    +      -       -      +
    138A  LEU      3.0    10.2    +      -       -      +
    140A  ASP*     1.3    76.2    -      -       -      +
    142A  GLY*     1.3    60.4    +      -       -      +
    143A  ILE*     3.6     8.9    +      -       +      +
    234A  GLY      5.2     3.5    -      -       -      +
    236A  CYS*     3.5    31.9    -      -       +      -
    261A  ARG*     3.5    23.6    -      -       +      +
----------------------------------------------------------
 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