Contacts of the helix formed by residues 120 - 144 (chain 6) in PDB entry 2X17


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 LEU 120 (chain 6).
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     106  LEU*     5.2     0.2    -      -       +      -
     576  PHE*     4.2    21.5    -      -       +      -
    1016  ILE*     4.3    15.4    -      -       +      +
    1046  LEU*     3.5    59.7    -      -       +      +
    1056  ALA*     3.8     8.5    -      -       +      +
    1086  ALA*     4.6     2.0    -      -       +      -
    1166  THR*     2.9    34.3    +      -       +      +
    1176  ARG*     4.1     9.9    -      -       -      +
    1186  ALA      3.4     0.4    -      -       -      -
    1196  PHE*     1.3    81.9    -      -       +      +
    1216  GLU*     1.3    62.7    +      -       -      +
    1226  TRP      3.2     0.7    -      -       -      -
    1236  PHE*     3.1    18.8    +      -       +      +
    1246  ILE*     3.1    21.2    +      -       +      +
----------------------------------------------------------
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Residues in contact with GLU 121 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    1211  GLU*     4.1    16.8    -      -       -      +
    1175  ARG*     4.8     0.9    +      -       -      +
    1185  ALA*     3.4    34.2    -      -       -      +
    1215  GLU*     4.1    18.8    -      -       +      +
    1176  ARG*     3.0    37.6    +      -       -      +
    1186  ALA      3.3    16.2    -      -       -      +
    1196  PHE      3.1     1.0    -      -       -      -
    1206  LEU*     1.3    77.7    -      -       -      +
    1226  TRP*     1.3    61.8    +      -       -      +
    1246  ILE*     3.5     9.6    +      -       -      +
    1256  ASN*     3.1    36.3    +      -       -      +
----------------------------------------------------------
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Residues in contact with TRP 122 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     536  HIS*     3.8     9.9    -      +       -      -
     566  ARG*     3.3    55.9    -      -       -      +
    1186  ALA      4.4     1.6    +      -       -      +
    1196  PHE*     3.5    13.5    +      -       +      +
    1206  LEU      3.2     0.2    -      -       -      -
    1216  GLU*     1.3    80.4    -      -       -      +
    1236  PHE*     1.3    89.8    +      +       +      +
    1256  ASN*     3.6     6.2    +      -       -      +
    1266  GLU*     3.0    49.1    +      -       +      +
    170O  MET*     3.5    30.3    -      -       +      -
----------------------------------------------------------
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Residues in contact with PHE 123 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     176  GLU*     4.4     8.1    -      -       -      -
     536  HIS*     3.6    32.5    -      -       +      -
     566  ARG*     3.7    18.2    -      -       +      -
     576  PHE*     3.4    35.4    -      +       -      -
    1016  ILE*     4.1    22.0    -      -       +      -
    1196  PHE*     3.5    42.2    -      +       -      -
    1206  LEU*     3.1    12.0    +      -       -      +
    1226  TRP*     1.3    98.5    -      +       +      +
    1246  ILE*     1.3    58.6    +      -       -      +
    1266  GLU*     3.7    11.4    -      -       -      +
    1276  GLN*     2.9    36.1    +      -       +      +
----------------------------------------------------------
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Residues in contact with ILE 124 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    1145  TYR*     3.4    42.0    -      -       +      +
    1155  SER*     3.7    13.9    +      -       -      +
    1185  ALA*     3.8     8.5    -      -       +      -
    1016  ILE*     3.9    18.6    -      -       +      -
    1026  TYR*     4.5     6.7    -      -       +      -
    1056  ALA*     4.5     9.4    -      -       +      -
    1176  ARG*     3.6    36.6    -      -       -      +
    1206  LEU*     3.1    14.9    +      -       +      +
    1216  GLU*     3.9    12.3    -      -       -      +
    1226  TRP      3.4     0.2    -      -       -      -
    1236  PHE*     1.3    77.3    -      -       -      +
    1256  ASN*     1.3    60.8    +      -       -      +
    1276  GLN*     3.6     4.2    +      -       -      +
    1286  VAL*     3.3    22.1    +      -       -      +
----------------------------------------------------------
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Residues in contact with ASN 125 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    1155  SER      5.0     1.6    -      -       -      +
    1185  ALA*     3.5    33.8    +      -       -      +
    1195  PHE*     4.1     4.7    +      -       -      +
    1216  GLU*     3.1    33.7    +      -       -      +
    1226  TRP*     3.9     5.6    -      -       -      +
    1236  PHE      3.3     0.2    -      -       -      -
    1246  ILE*     1.3    74.5    -      -       -      +
    1266  GLU*     1.3    63.8    +      -       -      +
    1286  VAL*     3.5    21.0    +      -       -      +
    1296  GLU*     3.7    11.1    +      -       -      +
----------------------------------------------------------
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Residues in contact with GLU 126 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     536  HIS*     3.1    16.6    +      -       -      -
    1226  TRP*     3.0    39.8    +      -       +      +
    1236  PHE*     3.7    14.7    -      -       -      +
    1246  ILE      3.3     0.2    -      -       -      -
    1256  ASN*     1.3    77.1    -      -       -      +
    1276  GLN*     1.3    81.4    +      -       -      +
    1296  GLU*     3.1    25.9    +      -       +      +
    1306  GLU*     3.0    48.7    +      -       -      +
   11726   AG      3.6    15.0    -      -       -      -
    170O  MET*     4.2     7.6    -      -       +      -
----------------------------------------------------------
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Residues in contact with GLN 127 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     645  ARG*     5.3     0.7    -      -       -      -
     176  GLU*     4.8     4.8    +      -       -      -
     506  GLU*     5.2     2.0    +      -       -      -
     536  HIS*     4.9     3.0    +      -       -      -
     946  GLU*     3.0    32.5    +      -       -      +
     976  ILE*     3.7    27.5    -      -       +      +
     986  SER*     3.1    31.9    +      -       -      +
    1016  ILE*     4.6     8.5    -      -       +      -
    1236  PHE*     2.9    22.2    +      -       +      +
    1246  ILE*     4.1     5.6    -      -       -      +
    1256  ASN      3.4     0.2    -      -       -      -
    1266  GLU*     1.3    97.3    +      -       -      +
    1286  VAL*     1.3    59.5    +      -       -      +
    1296  GLU      3.3     0.2    -      -       -      -
    1306  GLU*     3.8     7.4    +      -       -      +
    1316  GLU*     3.1    34.9    +      -       -      +
----------------------------------------------------------
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Residues in contact with VAL 128 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     605  TYR*     4.3    15.9    -      -       +      -
     635  ASP*     3.9    29.2    -      -       +      +
     645  ARG*     4.1    24.2    -      -       -      +
    1155  SER*     4.0    28.0    -      -       -      +
    1246  ILE      3.3    17.5    +      -       -      +
    1256  ASN*     3.6    13.2    -      -       -      +
    1266  GLU      3.2     0.2    -      -       -      -
    1276  GLN*     1.3    77.6    -      -       -      +
    1296  GLU*     1.3    62.5    +      -       +      +
    1316  GLU*     4.1     1.4    -      -       -      +
    1326  ALA*     3.2    23.7    +      -       -      +
----------------------------------------------------------
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Residues in contact with GLU 129 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     635  ASP*     5.6     5.8    -      -       -      +
    1256  ASN      3.7    10.7    +      -       -      +
    1266  GLU*     3.1    13.2    +      -       -      +
    1286  VAL*     1.3    80.9    -      -       +      +
    1306  GLU*     1.3    52.8    +      -       +      +
    1326  ALA*     3.4     5.4    +      -       -      +
    1336  SER*     2.8    35.5    +      -       -      -
    170O  MET*     3.8    24.8    -      -       +      +
----------------------------------------------------------
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Residues in contact with GLU 130 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     466  GLN*     2.8    35.0    +      -       -      +
     496  GLU*     4.4     0.9    -      -       -      +
     506  GLU*     3.0    13.5    -      -       -      +
     536  HIS*     3.2    10.1    -      -       -      -
     946  GLU*     3.0    36.2    -      -       -      +
    1266  GLU*     3.0    33.5    +      -       -      +
    1276  GLN*     3.7     8.0    +      -       -      +
    1296  GLU*     1.3    77.7    -      -       +      +
    1316  GLU*     1.3    61.1    +      -       -      +
    1336  SER*     3.5     6.8    -      -       -      -
    1346  VAL*     2.9    36.5    +      -       +      +
   11726   AG      4.2     2.9    -      -       -      -
    170O  MET*     5.5     2.4    -      -       +      +
----------------------------------------------------------
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Residues in contact with GLU 131 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
      15  MET      5.8     2.3    +      -       -      -
     635  ASP      5.1     3.8    -      -       -      +
     645  ARG*     3.9    25.0    +      -       -      +
     916  TYR*     3.7    22.9    +      -       +      -
     946  GLU*     4.1    22.2    -      -       +      +
     956  LYS*     3.8    23.5    -      -       -      +
     986  SER*     2.7    31.8    +      -       -      +
    1026  TYR*     4.9     0.2    +      -       -      -
    1276  GLN      3.1    18.4    +      -       -      +
    1286  VAL*     4.1     3.8    -      -       -      +
    1306  GLU*     1.3    76.2    -      -       -      +
    1326  ALA*     1.3    57.4    +      -       -      +
    1346  VAL*     3.5     0.4    +      -       -      -
    1356  LYS*     3.0    30.9    +      -       -      +
----------------------------------------------------------
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Residues in contact with ALA 132 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     625  TYR      5.3     0.9    -      -       -      +
     635  ASP*     3.6    41.2    +      -       -      +
    1286  VAL      3.2    17.7    +      -       -      +
    1296  GLU*     3.7     4.5    -      -       -      +
    1316  GLU*     1.3    77.4    -      -       -      +
    1336  SER*     1.3    58.7    +      -       -      +
    1356  LYS*     4.1     5.1    -      -       -      +
    1366  LYS*     3.1    29.8    +      -       -      +
----------------------------------------------------------
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Residues in contact with SER 133 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     426  TRP*     3.7    20.2    -      -       -      -
     466  GLN*     5.1     3.1    +      -       -      -
    1296  GLU      2.8    19.0    +      -       -      -
    1306  GLU*     3.2    10.7    +      -       -      -
    1326  ALA*     1.3    77.8    -      -       -      +
    1346  VAL*     1.3    62.7    +      -       -      +
    1366  LYS*     3.8     6.0    +      -       -      +
    1376  ILE*     3.5    25.7    +      -       -      +
    1616  ARG*     5.2     0.5    +      -       -      -
----------------------------------------------------------
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Residues in contact with VAL 134 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     246  TYR*     4.9     6.3    -      -       +      +
     426  TRP*     4.4    17.3    -      -       +      -
     436  MET*     6.5     0.4    -      -       +      -
     466  GLN*     5.6     4.5    -      -       +      +
     876  PHE*     3.9    26.6    -      -       +      +
     906  ALA*     4.1     6.1    -      -       +      -
     916  TYR*     3.7    37.2    -      -       +      +
     946  GLU*     4.1    19.3    -      -       +      -
    1306  GLU*     2.9    21.5    +      -       +      +
    1316  GLU      4.1     2.5    -      -       -      +
    1336  SER*     1.3    77.4    -      -       -      +
    1356  LYS*     1.3    58.5    +      -       -      +
    1376  ILE*     3.3     3.0    +      -       -      -
    1386  LEU*     3.0    25.3    +      -       -      +
----------------------------------------------------------
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Residues in contact with LYS 135 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     655  ASN*     3.4    42.3    +      -       +      +
     916  TYR*     3.5    40.1    -      -       +      +
    1316  GLU      3.0    20.2    +      -       -      +
    1326  ALA*     4.1     5.4    -      -       -      +
    1346  VAL*     1.3    77.0    -      -       -      +
    1366  LYS*     1.3    56.9    +      -       -      +
    1386  LEU*     3.6    12.3    -      -       +      +
    1396  ASP*     2.7    69.5    +      -       -      +
    1426  LYS*     5.5     4.5    -      -       -      +
----------------------------------------------------------
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Residues in contact with LYS 136 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    1326  ALA      3.1    20.6    +      -       -      +
    1336  SER*     3.9     8.1    -      -       -      +
    1346  VAL      3.3     0.2    -      -       -      -
    1356  LYS*     1.3    77.3    -      -       -      +
    1376  ILE*     1.3    64.4    +      -       +      +
    1396  ASP*     3.6     7.1    +      -       -      +
    1406  LYS*     3.3    50.9    +      -       +      +
     35N  GLY*     5.7     4.3    -      -       -      +
     37N  GLU*     3.0    44.5    +      -       +      +
----------------------------------------------------------
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Residues in contact with ILE 137 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     396  PHE*     4.3     7.2    -      -       +      -
     426  TRP*     3.5    38.4    -      -       +      +
     876  PHE*     3.7    36.6    -      -       +      -
    1336  SER*     3.5    13.2    -      -       -      +
    1346  VAL      3.3     2.1    +      -       -      +
    1356  LYS      3.3     0.4    -      -       -      -
    1366  LYS*     1.3    79.7    -      -       +      +
    1386  LEU*     1.3    65.6    +      -       -      +
    1406  LYS*     3.2    10.2    +      -       +      +
    1416  LEU*     3.0    24.4    +      -       +      +
    1546  LEU*     4.7     9.2    -      -       +      -
    1586  LEU*     3.8    32.3    -      -       +      -
----------------------------------------------------------
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Residues in contact with LEU 138 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     846  LEU*     3.9     3.3    -      -       +      +
     876  PHE*     3.4    40.3    -      -       +      +
     886  GLU*     3.8    22.4    -      -       +      +
     916  TYR*     3.6    30.7    -      -       +      -
    1346  VAL      3.0    17.0    +      -       -      +
    1356  LYS*     3.6    11.9    -      -       +      +
    1376  ILE*     1.3    75.8    -      -       -      +
    1396  ASP*     1.3    61.6    +      -       -      +
    1416  LEU*     3.1     8.1    +      -       -      +
    1426  LYS*     3.0    54.1    +      -       +      +
----------------------------------------------------------
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Residues in contact with ASP 139 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     655  ASN*     4.5     2.6    -      -       -      +
    1356  LYS*     2.7    55.6    +      -       -      +
    1366  LYS*     3.8     7.8    -      -       -      +
    1386  LEU*     1.3    82.3    -      -       -      +
    1406  LYS*     1.3    58.1    +      -       +      +
    1426  LYS*     3.4    15.7    +      -       -      +
    1436  PHE*     3.1    24.9    +      -       -      +
     33N  ASP      5.7     0.5    -      -       -      +
     34N  LEU      6.0     1.1    -      -       -      +
     35N  GLY*     5.8     9.0    -      -       -      -
----------------------------------------------------------
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Residues in contact with LYS 140 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    1366  LYS*     3.3    43.7    +      -       -      +
    1376  ILE*     3.2    13.1    +      -       +      +
    1396  ASP*     1.3    78.6    -      -       +      +
    1416  LEU*     1.3    57.9    +      -       -      +
    1426  LYS      3.4     0.2    -      -       -      -
    1436  PHE*     3.4    13.4    -      -       +      +
    1446  ALA*     3.2    25.5    +      -       -      +
    1506  ILE*     5.0     1.0    -      -       -      +
    1546  LEU*     3.8    35.0    -      -       +      +
    1576  GLU*     3.8    20.0    +      -       -      -
     35N  GLY*     4.5    17.5    -      -       -      +
    152N  PHE*     4.5    18.8    -      -       +      -
    155N  ASP*     5.4     7.0    +      -       -      -
----------------------------------------------------------
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Residues in contact with LEU 141 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     396  PHE*     4.2    12.6    -      -       +      -
     836  PRO*     3.5    31.6    -      -       +      +
     846  LEU*     3.7    26.2    -      -       +      +
     876  PHE*     3.6    31.6    -      -       +      -
    1376  ILE*     3.0    21.7    +      -       +      +
    1386  LEU*     3.1     7.4    +      -       -      +
    1406  LYS*     1.3    76.2    -      -       -      +
    1426  LYS*     1.3    62.2    +      -       -      +
    1436  PHE      3.2     1.3    -      -       -      -
    1446  ALA*     3.3    23.4    +      -       +      +
    1456  LYS*     3.7     3.5    +      -       -      -
    1516  LEU*     3.8    28.7    -      -       +      -
    1546  LEU*     4.4     7.2    -      -       +      -
----------------------------------------------------------
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Residues in contact with LYS 142 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     846  LEU*     3.7    19.5    -      -       +      -
     886  GLU*     4.1    14.4    -      -       -      -
    1356  LYS*     5.5     3.8    -      -       -      +
    1386  LEU*     3.0    31.4    +      -       +      +
    1396  ASP*     3.6    19.9    +      -       -      +
    1416  LEU*     1.3    75.0    -      -       -      +
    1436  PHE*     1.3    60.8    +      -       -      +
    1456  LYS*     3.3    34.9    -      -       -      +
----------------------------------------------------------
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Residues in contact with PHE 143 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    1396  ASP      3.1    14.5    +      -       -      +
    1406  LYS*     3.4    17.3    -      -       +      +
    1416  LEU      3.2     0.2    -      -       -      -
    1426  LYS*     1.3    77.9    -      -       -      +
    1446  ALA*     1.3    56.4    +      -       -      +
    1456  LYS      3.6     2.1    +      -       -      -
    1476  SER*     5.6     0.2    -      -       -      -
    1506  ILE*     4.4    13.1    -      -       +      +
     34N  LEU      5.5     7.6    -      -       -      -
     36N  LEU*     5.3     9.0    -      -       +      -
    148N  PRO*     3.6    40.7    -      -       +      +
    151N  LEU*     3.8    31.0    -      -       +      -
    152N  PHE*     4.6    21.1    -      +       +      -
----------------------------------------------------------
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Residues in contact with ALA 144 (chain 6). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    1406  LYS      3.2    15.1    +      -       -      +
    1416  LEU*     3.3    14.2    +      -       +      +
    1426  LYS      3.3     0.4    -      -       -      -
    1436  PHE*     1.3    78.2    -      -       -      +
    1456  LYS*     1.3    64.4    +      -       -      +
    1466  ASP      3.8     0.4    -      -       -      -
    1476  SER*     3.9    18.4    -      -       -      +
    1506  ILE*     3.6    37.7    -      -       +      -
    1516  LEU*     4.5     9.0    -      -       +      +
    1546  LEU*     4.9     3.4    -      -       +      -
----------------------------------------------------------
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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