Contacts of the helix formed by residues 256 - 283 (chain A) in PDB entry 3N4U


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 ASP 256 (chain A).
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    254A  HIS*     3.0    23.2    +      -       +      -
    255A  LYS*     1.3    82.0    -      -       +      +
    257A  ILE*     1.3    62.0    +      -       -      +
    258A  PRO*     3.5    14.3    -      -       -      +
    259A  THR*     2.4    44.7    +      -       -      +
    260A  VAL      3.3     4.5    +      -       -      -
----------------------------------------------------------
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Residues in contact with ILE 257 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    246A  SER*     6.4     0.2    -      -       -      -
    249A  LEU*     4.1    34.8    -      -       +      -
    250A  ASN*     3.6    27.8    -      -       -      +
    254A  HIS*     4.1    24.2    -      -       +      +
    255A  LYS      3.9     0.8    -      -       -      -
    256A  ASP*     1.3    74.5    -      -       -      +
    258A  PRO*     1.3    72.9    -      -       +      +
    260A  VAL*     2.9    16.4    +      -       -      +
    261A  LEU*     2.9    32.9    +      -       +      +
----------------------------------------------------------
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Residues in contact with PRO 258 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    256A  ASP*     3.4    14.1    -      -       -      +
    257A  ILE*     1.3    95.8    -      -       +      +
    259A  THR*     1.3    56.1    +      -       -      +
    261A  LEU*     3.4    13.0    +      -       +      +
    262A  GLU*     3.1    31.4    +      -       -      +
----------------------------------------------------------
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Residues in contact with THR 259 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    185A  ILE*     4.5    25.0    -      -       +      +
    227A  ASP*     4.3     3.8    -      -       -      +
    256A  ASP*     2.4    37.3    +      -       -      +
    258A  PRO*     1.3    76.0    -      -       -      +
    260A  VAL*     1.3    66.5    +      -       -      +
    262A  GLU*     3.3     9.6    +      -       -      +
    263A  LYS*     3.0    49.4    +      -       +      +
----------------------------------------------------------
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Residues in contact with VAL 260 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    227A  ASP*     3.5    17.3    -      -       -      +
    230A  PHE*     4.4    10.5    -      -       +      -
    231A  ILE*     3.9    14.6    -      -       +      +
    234A  MET*     3.5    28.3    -      -       +      -
    249A  LEU*     4.7     8.1    -      -       +      -
    254A  HIS*     3.1    45.5    -      -       +      +
    256A  ASP      3.7     1.3    -      -       -      +
    257A  ILE*     2.9    10.8    +      -       -      +
    259A  THR*     1.3    77.3    -      -       -      +
    261A  LEU*     1.3    60.9    -      -       +      +
    263A  LYS*     3.2     7.5    +      -       -      +
    264A  TYR*     3.0    21.3    +      -       -      +
----------------------------------------------------------
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Residues in contact with LEU 261 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    234A  MET*     4.4    11.0    -      -       +      -
    242A  MET*     3.6    34.3    -      -       +      -
    249A  LEU*     5.4     0.4    -      -       +      -
    257A  ILE*     2.9    35.6    +      -       +      +
    258A  PRO*     3.6    13.2    -      -       +      +
    260A  VAL*     1.3    76.3    -      -       +      +
    262A  GLU*     1.3    62.3    +      -       -      +
    264A  TYR*     3.4     8.7    +      -       +      +
    265A  ARG*     3.1    22.0    +      -       -      +
----------------------------------------------------------
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Residues in contact with GLU 262 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    183A  ASN*     5.2     6.4    +      -       -      -
    185A  ILE*     3.7    33.3    -      -       +      +
    186A  TYR*     4.5    11.5    +      -       -      +
    258A  PRO*     3.1    17.0    +      -       -      +
    259A  THR*     3.5    12.4    +      -       -      +
    260A  VAL      3.2     0.2    -      -       -      -
    261A  LEU*     1.3    74.7    -      -       -      +
    263A  LYS*     1.3    65.6    +      -       +      +
    265A  ARG*     3.1    16.1    +      -       +      +
    266A  MET*     3.0    21.1    +      -       -      +
----------------------------------------------------------
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Residues in contact with LYS 263 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    185A  ILE*     3.4    26.1    +      -       +      -
    186A  TYR*     4.1    26.9    -      -       +      +
    188A  LYS      5.5     0.6    +      -       -      -
    189A  TYR*     4.3     8.5    -      -       -      +
    225A  ASP*     2.6    33.4    +      -       -      +
    227A  ASP*     2.8    33.7    +      -       +      +
    228A  ASN*     5.1     2.7    -      -       -      +
    231A  ILE*     3.5    17.9    -      -       +      -
    259A  THR*     3.0    30.4    +      -       +      +
    260A  VAL      3.2     2.6    +      -       -      +
    262A  GLU*     1.3    74.9    -      -       -      +
    264A  TYR*     1.3    57.4    +      -       -      +
    266A  MET*     3.3     7.9    +      -       +      +
    267A  LYS*     2.9    32.7    +      -       +      +
----------------------------------------------------------
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Residues in contact with TYR 264 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    231A  ILE*     3.6    34.6    -      -       +      +
    234A  MET*     3.7    40.7    +      -       +      -
    235A  GLU*     3.1    41.6    -      -       +      +
    236A  ASP*     4.3     6.9    +      -       -      -
    242A  MET*     5.4     5.6    -      -       +      -
    260A  VAL      3.0     9.5    +      -       -      +
    261A  LEU*     3.7    11.0    -      -       +      +
    262A  GLU      3.2     0.2    -      -       -      -
    263A  LYS*     1.3    76.3    -      -       -      +
    265A  ARG*     1.3    58.3    +      -       -      +
    267A  LYS*     3.2     2.5    +      -       +      -
    268A  GLU*     2.9    64.4    +      -       +      +
----------------------------------------------------------
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Residues in contact with ARG 265 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    261A  LEU      3.1    13.1    +      -       -      +
    262A  GLU*     3.3    18.0    -      -       -      +
    264A  TYR*     1.3    81.4    -      -       +      +
    266A  MET*     1.3    62.0    +      -       -      +
    268A  GLU*     3.6    27.1    +      -       -      +
    269A  LYS*     3.7    16.6    -      -       +      +
----------------------------------------------------------
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Residues in contact with MET 266 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    146A  PHE*     3.8    20.6    -      -       +      -
    176A  PHE*     5.1     1.0    -      -       -      -
    180A  ILE*     3.5    28.5    -      -       +      -
    186A  TYR*     3.4    46.4    +      -       +      +
    262A  GLU      3.0     6.8    +      -       -      +
    263A  LYS*     3.6    12.8    -      -       +      +
    265A  ARG*     1.3    75.2    -      -       -      +
    267A  LYS*     1.3    94.5    +      -       +      +
    269A  LYS*     3.3    11.9    +      -       -      +
    270A  TYR*     2.9    41.6    +      -       -      +
----------------------------------------------------------
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Residues in contact with LYS 267 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    146A  PHE*     4.3    19.9    -      -       -      -
    228A  ASN*     4.0    26.3    +      -       -      +
    231A  ILE*     4.2    24.6    -      -       +      +
    263A  LYS*     2.9    21.9    +      -       +      +
    264A  TYR*     3.2     5.6    +      -       +      +
    266A  MET*     1.3    99.8    -      -       +      +
    268A  GLU*     1.3    57.7    +      -       -      +
    270A  TYR*     3.7    18.2    -      -       +      -
    271A  TRP*     2.6    37.6    +      -       -      +
----------------------------------------------------------
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Residues in contact with GLU 268 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    235A  GLU*     6.2     0.7    -      -       +      -
    264A  TYR*     2.9    52.0    +      -       +      +
    265A  ARG*     3.6    21.9    -      -       -      +
    266A  MET      3.2     0.2    -      -       -      -
    267A  LYS*     1.3    77.9    -      -       -      +
    269A  LYS*     1.3    66.1    +      -       +      +
    271A  TRP*     3.3    10.9    +      -       -      +
    272A  SER*     3.3    14.9    +      -       -      -
----------------------------------------------------------
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Residues in contact with LYS 269 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    176A  PHE*     4.0    25.5    -      -       +      -
    180A  ILE*     6.4     0.7    -      -       -      -
    265A  ARG*     3.7    20.0    -      -       +      +
    266A  MET*     3.3     8.0    +      -       -      +
    267A  LYS      3.2     0.2    -      -       -      -
    268A  GLU*     1.3    78.2    -      -       +      +
    270A  TYR*     1.3    65.4    +      -       -      +
    272A  SER*     3.2    22.3    +      -       -      -
    273A  PHE*     3.5    14.0    -      -       +      -
    294A  GLU*     6.5     0.4    -      -       -      -
----------------------------------------------------------
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Residues in contact with TYR 270 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    146A  PHE*     3.8    26.4    -      +       -      -
    149A  LYS*     3.9     5.4    -      -       +      +
    150A  ILE*     3.7    21.7    +      -       +      -
    153A  ASP*     2.7    31.9    +      -       +      +
    176A  PHE*     4.0    18.8    -      +       +      -
    177A  TYR*     3.6    24.9    -      +       -      -
    180A  ILE*     5.1     4.5    -      -       +      -
    266A  MET*     2.9    28.1    +      -       -      +
    267A  LYS*     3.4    30.1    -      -       +      +
    269A  LYS*     1.3    77.4    -      -       -      +
    271A  TRP*     1.3    63.6    +      -       -      +
    273A  PHE*     3.0    14.6    +      -       -      +
    274A  GLU*     3.1    30.7    +      -       +      +
----------------------------------------------------------
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Residues in contact with TRP 271 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    235A  GLU*     6.0     6.3    -      -       +      -
    267A  LYS      2.6    19.8    +      -       -      +
    268A  GLU*     3.7     7.2    -      -       -      +
    270A  TYR*     1.3    72.6    -      -       -      +
    272A  SER*     1.3    56.5    +      -       -      +
    274A  GLU*     2.8    44.3    +      -       +      +
    275A  LYS*     2.8    79.6    +      -       +      +
    278A  TYR*     4.4    17.3    -      +       -      -
    287A  TRP*     4.8    17.2    -      +       -      +
----------------------------------------------------------
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Residues in contact with SER 272 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    268A  GLU      3.3    12.5    +      -       -      -
    269A  LYS*     3.2    12.4    +      -       -      -
    270A  TYR      3.1     0.6    -      -       -      -
    271A  TRP*     1.3    79.7    -      -       -      +
    273A  PHE*     1.3    66.2    +      -       -      +
    275A  LYS*     3.8    16.4    +      -       -      +
    276A  ILE*     3.7    18.7    +      -       -      +
    290A  GLU      6.2     0.2    -      -       -      -
    291A  GLY*     3.8    13.0    -      -       -      -
    294A  GLU*     4.6    25.6    +      -       -      +
----------------------------------------------------------
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Residues in contact with PHE 273 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    157A  ILE*     3.5    20.6    -      -       +      +
    172A  LYS      5.0     0.2    -      -       -      -
    173A  VAL*     4.3    15.3    -      -       +      -
    176A  PHE*     3.6    51.8    -      +       +      -
    177A  TYR*     3.5    23.3    -      +       -      +
    269A  LYS*     3.5    15.0    -      -       +      -
    270A  TYR*     3.0     7.4    +      -       +      +
    272A  SER*     1.3    79.3    -      -       -      +
    274A  GLU*     1.3    68.1    +      -       -      +
    276A  ILE*     3.0    26.3    +      -       +      +
    277A  ILE      3.8     0.5    +      -       -      -
    291A  GLY      5.8     0.4    -      -       -      -
    294A  GLU*     5.2    12.3    -      -       +      -
    295A  ILE*     3.9    30.3    -      -       +      -
    298A  ILE*     3.8    24.5    -      -       +      -
----------------------------------------------------------
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Residues in contact with GLU 274 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    149A  LYS*     4.0    20.8    +      -       -      -
    153A  ASP*     4.1    17.9    -      -       -      +
    157A  ILE*     5.3     0.7    -      -       -      -
    177A  TYR*     4.9     1.0    +      -       -      -
    270A  TYR*     3.1    27.2    +      -       +      +
    271A  TRP*     2.8    40.2    -      -       +      +
    273A  PHE*     1.3    75.1    -      -       -      +
    275A  LYS*     1.3    55.0    +      -       -      +
    277A  ILE*     2.8    41.0    +      -       +      +
    278A  TYR*     3.4    27.9    +      -       +      -
----------------------------------------------------------
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Residues in contact with LYS 275 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    271A  TRP*     2.8    73.6    +      -       +      +
    272A  SER*     3.8    15.1    +      -       -      +
    273A  PHE      3.2     0.2    -      -       -      -
    274A  GLU*     1.3    73.3    -      -       -      +
    276A  ILE*     1.3    54.9    +      -       -      +
    277A  ILE      3.2     0.2    -      -       -      -
    278A  TYR*     4.4     5.8    -      -       -      -
    279A  GLY*     2.7    33.2    +      -       -      -
    287A  TRP*     3.3    55.8    -      -       +      +
    290A  GLU*     4.7    11.7    +      -       -      -
----------------------------------------------------------
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Residues in contact with ILE 276 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    157A  ILE*     4.6    10.5    -      -       +      -
    160A  LEU*     4.6     2.0    -      -       +      +
    161A  LEU*     3.7    31.9    -      -       +      -
    272A  SER      3.7    10.5    +      -       -      +
    273A  PHE*     3.0    24.1    +      -       +      +
    275A  LYS*     1.3    76.5    -      -       -      +
    277A  ILE*     1.3    59.6    +      -       +      +
    279A  GLY*     4.7     0.9    -      -       -      -
    280A  LYS*     2.9    30.0    +      -       -      +
    287A  TRP      4.3     5.8    -      -       -      +
    288A  TYR*     4.2    16.0    -      -       +      +
    291A  GLY*     3.7    28.0    -      -       -      +
    292A  LEU*     4.1     3.4    -      -       +      +
    295A  ILE*     3.6    31.6    -      -       +      -
----------------------------------------------------------
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Residues in contact with ILE 277 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    153A  ASP*     4.5     9.9    -      -       -      +
    156A  LYS*     3.9    34.8    -      -       +      +
    157A  ILE*     3.1    36.8    -      -       +      -
    160A  LEU*     3.3    27.7    -      -       +      +
    273A  PHE      4.1     2.2    -      -       -      +
    274A  GLU*     2.8    21.8    +      -       +      +
    276A  ILE*     1.3    77.2    -      -       -      +
    278A  TYR*     1.3    70.7    +      -       +      +
    280A  LYS*     4.1     1.7    -      -       -      +
    281A  GLU*     3.1    23.6    +      -       +      +
----------------------------------------------------------
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Residues in contact with TYR 278 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     32A  ASN*     3.5    27.7    +      -       +      -
    149A  LYS*     5.1     6.6    +      -       -      -
    271A  TRP*     4.4    16.3    -      +       -      -
    274A  GLU*     3.4    43.7    +      -       +      -
    275A  LYS*     4.4     2.7    -      -       -      +
    277A  ILE*     1.3    83.1    -      -       +      +
    279A  GLY*     1.3    56.2    +      -       -      +
    281A  GLU*     4.2     5.8    -      -       +      -
    282A  TYR*     2.6    65.7    +      +       +      +
    287A  TRP*     3.7    24.7    -      +       +      -
----------------------------------------------------------
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Residues in contact with GLY 279 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    275A  LYS      2.7    25.1    +      -       -      -
    276A  ILE      3.8     0.9    -      -       -      -
    277A  ILE      3.2     0.2    -      -       -      -
    278A  TYR*     1.3    74.1    -      -       -      +
    280A  LYS*     1.3    56.1    +      -       -      +
    283A  GLY*     2.9    24.4    +      -       -      -
    284A  TYR*     3.0    27.7    +      -       -      +
    287A  TRP*     3.9    11.6    -      -       -      -
    288A  TYR*     4.3     7.5    -      -       -      +
----------------------------------------------------------
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Residues in contact with LYS 280 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    160A  LEU*     3.4    50.4    +      -       +      +
    163A  ARG*     6.0     2.0    -      -       -      +
    276A  ILE      2.9    20.1    +      -       -      +
    277A  ILE      4.2     2.5    -      -       -      +
    279A  GLY*     1.3    71.6    -      -       -      +
    281A  GLU*     1.3    66.7    +      -       -      +
    283A  GLY*     3.7     6.3    +      -       -      -
    288A  TYR*     3.5    38.4    -      -       +      -
----------------------------------------------------------
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Residues in contact with GLU 281 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
      1A  MET*     4.2    24.2    -      -       +      +
    160A  LEU*     6.2     0.2    -      -       -      +
    277A  ILE*     3.1    19.4    +      -       +      +
    278A  TYR*     3.5     6.5    -      -       +      +
    280A  LYS*     1.3    79.7    -      -       -      +
    282A  TYR*     1.3    83.5    +      -       +      +
    283A  GLY*     3.1     0.6    +      -       -      -
----------------------------------------------------------
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Residues in contact with TYR 282 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
      1A  MET*     5.4     9.0    -      -       +      -
     31A  GLY      5.8     0.9    -      -       -      -
     32A  ASN*     3.0    41.1    +      -       -      +
     49A  LYS*     6.2     1.8    -      -       -      -
    278A  TYR*     2.6    50.1    +      +       +      +
    281A  GLU*     1.3    91.7    -      -       +      +
    283A  GLY*     1.3    61.5    +      -       -      +
    284A  TYR*     3.5    50.2    -      +       +      +
    287A  TRP*     4.2     5.8    -      +       -      -
----------------------------------------------------------
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Residues in contact with GLY 283 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    279A  GLY      2.9    10.4    +      -       -      -
    280A  LYS*     3.7     5.6    +      -       -      -
    281A  GLU      3.1     4.6    +      -       -      -
    282A  TYR*     1.3    80.9    -      -       -      +
    284A  TYR*     1.3    64.6    +      -       -      +
    285A  MET*     3.7     3.5    +      -       -      +
----------------------------------------------------------
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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