Contacts of the helix formed by residues 186 - 213 (chain A) in PDB entry 1IW1


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 186 (chain A).
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    185A  LEU*     1.3    76.2    -      -       -      +
    187A  ASP*     1.3    65.8    +      -       -      +
    188A  GLU*     3.4     8.6    +      -       -      +
    189A  GLN*     2.9    38.2    +      -       -      +
    190A  ARG*     2.9    21.9    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ASP 187 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    185A  LEU      5.5     0.3    -      -       -      +
    186A  SER*     1.3    74.1    -      -       -      +
    188A  GLU*     1.3    58.5    +      -       +      +
    190A  ARG*     3.3    10.6    +      -       -      +
    191A  GLU*     2.9    30.2    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with GLU 188 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    186A  SER*     3.2     8.1    +      -       -      +
    187A  ASP*     1.3    79.1    -      -       +      +
    189A  GLN*     1.3    59.5    +      -       +      +
    191A  GLU*     3.4    13.6    +      -       -      +
    192A  HIS*     3.0    29.9    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with GLN 189 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     68A  PHE*     4.2    13.9    -      -       -      -
    123A  PRO*     3.7    32.5    -      -       +      +
    184A  GLU      4.0     4.2    -      -       -      +
    185A  LEU*     3.4    17.1    -      -       +      -
    186A  SER*     2.9    39.9    +      -       -      +
    188A  GLU*     1.3    77.6    -      -       +      +
    190A  ARG*     1.3    58.0    +      -       -      +
    192A  HIS*     3.3     7.2    +      -       -      +
    193A  LEU*     2.9    30.1    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ARG 190 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
      4A  ALA*     3.2    27.8    +      -       -      +
      7A  GLY*     3.4     4.8    +      -       -      -
      8A  LEU*     3.4    45.7    -      -       +      +
     11A  GLU*     2.5    30.1    +      -       -      -
    185A  LEU*     4.2    20.8    -      -       +      +
    186A  SER      2.9    16.5    +      -       -      +
    187A  ASP*     3.7    11.0    -      -       -      +
    189A  GLN*     1.3    76.6    -      -       -      +
    191A  GLU*     1.3    62.7    +      -       -      +
    193A  LEU*     3.2     3.5    +      -       -      +
    194A  LEU*     2.9    40.1    +      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with GLU 191 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    187A  ASP      2.9    17.8    +      -       -      +
    188A  GLU*     3.7    12.3    -      -       -      +
    190A  ARG*     1.3    77.8    -      -       -      +
    192A  HIS*     1.3    62.7    +      -       -      +
    194A  LEU*     3.4     9.5    +      -       -      +
    195A  LYS*     3.0    60.4    +      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with HIS 192 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    112A  ARG*     4.0    19.3    -      -       -      -
    121A  ASP*     2.7    41.8    +      -       -      -
    123A  PRO*     4.1    12.1    -      -       +      -
    124A  ALA*     3.8     7.0    -      -       +      +
    188A  GLU      3.0    17.1    +      -       -      +
    189A  GLN*     3.5     7.2    -      -       -      +
    190A  ARG      3.2     0.2    -      -       -      -
    191A  GLU*     1.3    73.5    -      -       -      +
    193A  LEU*     1.3    61.3    -      -       -      +
    195A  LYS*     3.4     8.2    +      -       -      +
    196A  GLU*     2.9    36.1    +      -       -      +
    462B  HIS*     6.3     0.4    -      -       -      -
    464B  GLU*     5.7     3.5    +      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with LEU 193 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
      8A  LEU*     4.2    13.7    -      -       +      -
     12A  LEU*     3.7    34.1    -      -       +      -
    123A  PRO*     3.4    34.3    -      -       +      +
    126A  VAL*     3.8    22.0    -      -       +      -
    127A  ALA*     3.3    15.0    -      -       +      +
    183A  LEU*     4.9     1.6    -      -       +      -
    185A  LEU*     3.8    25.8    -      -       +      -
    189A  GLN      2.9    15.3    +      -       -      +
    190A  ARG*     3.2     5.8    +      -       -      +
    192A  HIS*     1.3    76.8    -      -       -      +
    194A  LEU*     1.3    64.4    +      -       -      +
    196A  GLU*     3.2     1.3    +      -       -      -
    197A  ALA*     2.9    19.6    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with LEU 194 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
      8A  LEU*     4.3     8.7    -      -       +      -
     11A  GLU*     3.5    37.5    -      -       +      +
     12A  LEU*     3.9    42.8    -      -       +      +
     15A  SER*     4.3    18.5    +      -       -      +
     16A  THR*     4.9     1.2    -      -       -      +
    190A  ARG*     2.9    32.9    +      -       +      +
    191A  GLU*     3.9     7.6    -      -       -      +
    193A  LEU*     1.3    78.6    -      -       +      +
    195A  LYS*     1.3    62.7    +      -       +      +
    197A  ALA*     3.3    12.6    +      -       -      +
    198A  THR*     3.3    14.4    +      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with LYS 195 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    191A  GLU*     3.0    50.5    +      -       +      +
    192A  HIS*     3.9     7.9    -      -       -      +
    194A  LEU*     1.3    76.8    -      -       +      +
    196A  GLU*     1.3    64.1    +      -       -      +
    198A  THR*     3.3     8.8    +      -       -      -
    199A  ASP*     3.1    27.3    +      -       -      +
    464B  GLU*     4.4    25.1    +      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with GLU 196 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    112A  ARG*     2.8    47.0    +      -       -      +
    124A  ALA*     3.7    21.9    -      -       +      +
    127A  ALA*     3.7     6.1    -      -       +      -
    128A  HIS*     2.8    39.0    +      -       +      +
    192A  HIS*     2.9    22.8    +      -       +      +
    193A  LEU      3.2     4.5    +      -       -      +
    195A  LYS*     1.3    78.1    -      -       -      +
    197A  ALA*     1.3    56.4    +      -       -      +
    199A  ASP*     3.1    17.9    +      -       -      +
    200A  ALA*     2.8    27.5    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 197 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     12A  LEU*     3.5    31.4    -      -       +      -
     16A  THR*     3.7    12.1    -      -       +      -
    127A  ALA*     3.6    13.4    -      -       +      +
    131A  VAL*     3.8    13.2    -      -       +      +
    193A  LEU      2.9    12.3    +      -       -      +
    194A  LEU      3.6     4.7    -      -       -      +
    195A  LYS      3.2     0.4    -      -       -      -
    196A  GLU*     1.3    74.5    -      -       -      +
    198A  THR*     1.3    65.3    +      -       -      +
    200A  ALA*     3.3     3.8    +      -       -      +
    201A  PHE*     3.2    27.2    +      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with THR 198 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     15A  SER*     3.9    20.3    +      -       -      -
     16A  THR*     4.0    10.2    -      -       -      +
     19A  ALA*     4.4    12.5    -      -       +      +
    194A  LEU      3.3     8.3    +      -       -      -
    195A  LYS*     3.3    11.5    +      -       -      -
    197A  ALA*     1.3    79.4    -      -       -      +
    199A  ASP*     1.3    66.2    +      -       -      +
    201A  PHE*     3.1     7.4    +      -       -      +
    202A  VAL*     3.0    32.4    +      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ASP 199 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    112A  ARG*     5.8     0.5    +      -       -      -
    195A  LYS*     3.1    20.6    +      -       -      +
    196A  GLU*     3.1    24.2    +      -       -      +
    198A  THR*     1.3    79.5    -      -       -      +
    200A  ALA*     1.3    57.9    +      -       -      +
    202A  VAL*     3.1    10.6    +      -       -      +
    203A  PHE*     2.9    48.7    +      -       +      -
    464B  GLU      5.5     2.3    -      -       -      +
    467B  ALA*     3.9    22.9    -      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 200 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    109A  TYR*     5.2     0.9    -      -       -      +
    128A  HIS*     3.6    35.1    -      -       +      +
    131A  VAL*     3.9    24.5    -      -       +      -
    196A  GLU      2.8    15.6    +      -       -      +
    197A  ALA*     3.5    10.1    -      -       -      +
    198A  THR      3.2     0.2    -      -       -      -
    199A  ASP*     1.3    74.2    -      -       -      +
    201A  PHE*     1.3    60.8    +      -       -      +
    203A  PHE*     3.3     4.5    +      -       -      +
    204A  ASN*     2.9    32.8    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with PHE 201 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     16A  THR*     3.6    33.0    -      -       -      -
     19A  ALA*     3.6    21.3    -      -       +      +
     20A  HIS*     3.6    42.0    -      +       +      -
     23A  ALA*     4.2    11.8    -      -       +      +
    130A  TYR*     4.7     0.9    -      +       -      -
    131A  VAL*     3.7    20.9    -      -       +      -
    197A  ALA      3.2    19.2    +      -       -      -
    198A  THR      3.1     8.7    +      -       -      +
    200A  ALA*     1.3    79.3    -      -       -      +
    202A  VAL*     1.3    57.9    +      -       -      +
    204A  ASN*     3.2     5.0    +      -       +      +
    205A  HIS*     2.9    28.8    +      -       -      +
    901A  HEM      3.5    51.6    -      +       +      -
----------------------------------------------------------
 Back to top of page

Residues in contact with VAL 202 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     19A  ALA*     5.3     5.4    -      -       +      -
     22A  LYS*     6.0     7.0    -      -       +      +
    198A  THR*     3.0    28.9    +      -       +      +
    199A  ASP*     3.1    13.9    +      -       -      +
    201A  PHE*     1.3    76.8    -      -       -      +
    203A  PHE*     1.3    63.9    +      -       -      +
    205A  HIS*     3.3     6.4    +      -       -      +
    206A  GLN*     3.1    21.0    +      -       -      +
    467B  ALA*     4.8     9.2    -      -       +      -
    468B  LYS*     3.7    36.7    +      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with PHE 203 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    105A  ALA*     4.7     3.2    -      -       -      +
    108A  ASP*     4.0    19.7    -      -       +      -
    109A  TYR*     3.7    42.4    -      +       +      -
    112A  ARG*     3.9    35.9    -      -       +      -
    128A  HIS*     4.1    11.2    -      +       -      -
    196A  GLU*     4.8     0.2    -      -       -      -
    199A  ASP*     2.9    35.2    +      -       +      -
    200A  ALA*     3.6     5.6    -      -       -      +
    202A  VAL*     1.3    75.2    -      -       -      +
    204A  ASN*     1.3    59.9    +      -       -      +
    206A  GLN*     3.1     8.3    +      -       +      +
    207A  VAL*     3.0    31.5    +      -       -      +
    467B  ALA*     3.4    39.7    -      -       +      -
    468B  LYS*     4.3    10.3    -      -       +      -
----------------------------------------------------------
 Back to top of page

Residues in contact with ASN 204 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     23A  ALA*     4.9     2.5    -      -       +      -
     52A  PHE*     3.9     5.2    -      -       -      -
    109A  TYR*     2.9    32.7    +      -       -      -
    131A  VAL*     4.2     8.1    -      -       -      +
    132A  ARG*     2.8    37.3    +      -       -      +
    200A  ALA      2.9    27.6    +      -       -      +
    201A  PHE*     3.2     8.9    +      -       -      +
    203A  PHE*     1.3    74.5    -      -       -      +
    205A  HIS*     1.3    65.3    +      -       -      +
    207A  VAL*     3.3     9.7    +      -       -      +
    208A  PHE*     3.2    28.1    +      -       -      -
    901A  HEM      3.8    20.3    -      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with HIS 205 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     19A  ALA      5.7     0.4    -      -       -      +
     22A  LYS*     3.4    59.1    +      -       +      +
     23A  ALA*     4.1    12.2    -      -       +      +
     26A  SER*     3.8    19.7    -      -       -      -
    201A  PHE      2.9    15.3    +      -       -      +
    202A  VAL*     3.7     8.0    +      -       -      +
    204A  ASN*     1.3    76.7    -      -       -      +
    206A  GLN*     1.3    68.5    +      -       -      +
    208A  PHE*     3.1    11.8    +      -       -      +
    209A  ALA*     2.9    36.3    +      -       +      +
    468B  LYS*     5.0     3.6    +      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with GLN 206 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    105A  ALA*     3.5    22.9    -      -       +      +
    202A  VAL      3.1     5.6    +      -       -      +
    203A  PHE*     3.6     8.3    -      -       +      +
    205A  HIS*     1.3    80.3    +      -       -      +
    207A  VAL*     1.3    65.0    +      -       -      +
    209A  ALA*     3.6    16.6    -      -       -      +
    210A  ASP*     2.9    43.2    +      -       -      +
    213A  LYS*     4.8     8.1    -      -       -      +
    468B  LYS*     2.8    48.9    +      -       +      +
    471B  VAL*     3.7    22.3    -      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with VAL 207 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     45A  LEU*     4.7     7.6    -      -       +      -
     48A  GLN*     4.6     6.1    -      -       +      -
     52A  PHE*     4.3    18.8    -      -       +      -
    103A  SER*     5.1     1.8    +      -       -      +
    105A  ALA*     3.6    14.1    -      -       +      -
    106A  VAL*     3.9    28.0    -      -       +      -
    109A  TYR*     4.1    20.0    -      -       +      -
    203A  PHE      3.0    19.5    +      -       -      +
    204A  ASN*     3.5    11.7    -      -       -      +
    205A  HIS      3.2     0.2    -      -       -      -
    206A  GLN*     1.3    76.0    -      -       -      +
    208A  PHE*     1.3    64.8    +      -       +      +
    210A  ASP*     3.4     1.9    +      -       -      +
    211A  LEU*     3.0    38.9    +      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with PHE 208 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     23A  ALA*     3.4    19.5    -      -       +      -
     26A  SER*     3.1    31.4    -      -       -      +
     28A  PHE*     3.4    30.8    -      +       +      +
     29A  MET*     3.4    35.4    -      -       +      -
     45A  LEU*     3.9    24.2    -      -       +      -
    132A  ARG*     5.6     0.9    -      -       -      -
    143A  ILE*     6.1     0.2    -      -       +      -
    204A  ASN*     3.2    14.6    +      -       +      -
    205A  HIS*     3.1     9.4    +      -       -      +
    207A  VAL*     1.3    77.2    -      -       +      +
    209A  ALA*     1.3    64.2    +      -       -      +
    211A  LEU*     3.2     5.1    +      -       -      +
    212A  GLY*     2.9    19.4    +      -       -      -
    901A  HEM      3.6    36.3    -      -       +      -
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 209 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     26A  SER*     5.3     1.7    -      -       -      -
    205A  HIS*     2.9    25.1    +      -       +      +
    206A  GLN*     3.2    25.8    +      -       -      +
    208A  PHE*     1.3    78.0    -      -       -      +
    210A  ASP*     1.3    64.6    +      -       -      +
    212A  GLY*     3.1    11.2    +      -       -      -
    213A  LYS*     3.2    24.6    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ASP 210 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    103A  SER*     4.1    20.4    -      -       -      +
    104A  PRO*     3.7    17.3    -      -       +      +
    105A  ALA*     3.0    29.8    +      -       +      +
    206A  GLN*     2.9    41.9    +      -       -      +
    207A  VAL      3.9     3.4    -      -       -      +
    209A  ALA*     1.3    75.9    -      -       -      +
    211A  LEU*     1.3    61.9    +      -       +      +
    213A  LYS*     3.1    33.1    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with LEU 211 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     28A  PHE*     3.8    34.1    -      -       +      -
     44A  ARG*     3.9    36.1    -      -       +      +
     45A  LEU*     3.6    36.3    -      -       +      +
     48A  GLN*     4.3    11.7    -      -       +      -
    207A  VAL*     3.0    28.1    +      -       +      +
    208A  PHE*     3.5     8.5    -      -       -      +
    210A  ASP*     1.3    76.4    -      -       -      +
    212A  GLY*     1.3    61.9    +      -       -      +
    213A  LYS      3.1     5.1    +      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with GLY 212 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     28A  PHE*     3.9    17.0    -      -       -      -
    208A  PHE      2.9    14.3    +      -       -      -
    209A  ALA*     3.1     7.3    +      -       -      -
    211A  LEU*     1.3    76.4    -      -       -      +
    213A  LYS*     1.3    59.7    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with LYS 213 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    206A  GLN*     4.8     5.5    -      -       -      +
    209A  ALA*     3.3    21.8    -      -       -      +
    210A  ASP*     3.1    32.2    +      -       -      +
    211A  LEU      3.1     5.2    -      -       -      -
    212A  GLY*     1.3    82.7    -      -       -      +
----------------------------------------------------------
 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