Contacts of the helix formed by residues 500 - 523 (chain A) in PDB entry 2IUK


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 VAL 500 (chain A).
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    499A  GLY*     1.3    70.9    -      -       -      -
    501A  ASP*     1.3    63.5    +      -       -      +
    502A  SER      3.2     2.5    -      -       -      -
    503A  THR*     2.9    24.3    +      -       -      +
    504A  ILE*     3.0    14.9    +      -       +      +
    749A  TYR*     3.9    23.1    -      -       +      +
    752A  MET*     3.5    27.8    -      -       +      -
    753A  VAL*     3.7    38.8    -      -       +      +
----------------------------------------------------------
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Residues in contact with ASP 501 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    493A  VAL*     5.3     0.7    -      -       -      +
    494A  LEU      4.5     4.6    -      -       -      +
    496A  ALA*     3.4    22.9    -      -       +      +
    498A  GLU      4.6     6.5    -      -       -      +
    499A  GLY      3.4     0.2    -      -       -      -
    500A  VAL*     1.3    81.1    -      -       -      +
    502A  SER*     1.3    55.5    +      -       -      +
    503A  THR      3.3     0.2    -      -       -      -
    504A  ILE*     3.9    17.3    -      -       -      +
    505A  TRP*     3.1    21.3    +      -       -      +
    749A  TYR*     5.4     1.9    +      -       -      -
----------------------------------------------------------
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Residues in contact with SER 502 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    365A  MET*     5.9     1.2    -      -       -      +
    496A  ALA*     3.2    32.5    -      -       -      +
    497A  THR      3.7    19.3    +      -       -      -
    498A  GLU      4.2     1.1    +      -       -      -
    499A  GLY      2.8    23.4    +      -       -      -
    501A  ASP*     1.3    76.3    -      -       -      +
    503A  THR*     1.3    59.6    +      -       -      +
    505A  TRP*     3.7     4.8    -      -       -      +
    506A  LEU*     3.1    25.5    +      -       -      +
----------------------------------------------------------
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Residues in contact with THR 503 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    499A  GLY      3.4    12.6    +      -       -      -
    500A  VAL*     2.9    13.3    +      -       -      -
    502A  SER*     1.3    79.2    +      -       -      +
    504A  ILE*     1.3    60.2    +      -       -      +
    505A  TRP      3.2     0.2    -      -       -      -
    506A  LEU*     3.5    11.8    +      -       +      +
    507A  LEU*     3.0    38.3    +      -       +      +
    752A  MET*     3.6    29.9    +      -       +      +
    756A  PRO*     3.5    39.9    -      -       +      +
----------------------------------------------------------
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Residues in contact with ILE 504 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    493A  VAL*     3.5    24.0    -      -       +      +
    500A  VAL*     3.0    10.4    +      -       +      +
    501A  ASP*     4.1    18.4    -      -       -      +
    503A  THR*     1.3    77.3    -      -       -      +
    505A  TRP*     1.3    61.3    +      -       -      +
    507A  LEU*     3.5     7.6    +      -       -      +
    508A  ALA*     3.1    20.8    +      -       -      +
    741A  ILE*     3.9    27.2    -      -       +      +
    742A  PRO      5.5     0.2    -      -       -      +
    749A  TYR*     4.2    19.7    -      -       +      +
    752A  MET*     3.6    29.2    -      -       +      -
----------------------------------------------------------
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Residues in contact with TRP 505 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    367A  ASP*     3.2    43.1    -      -       -      -
    471A  PRO*     3.2    31.9    -      -       +      -
    473A  ALA*     4.1     2.5    -      -       -      -
    474A  ILE*     3.6    32.9    -      -       +      +
    493A  VAL*     2.7    40.2    +      -       +      +
    494A  LEU      3.1    18.8    -      -       -      +
    495A  PRO*     3.7    30.1    -      -       +      -
    496A  ALA      4.5     7.4    -      -       -      +
    501A  ASP      3.1    16.9    +      -       -      +
    502A  SER*     3.9     7.6    -      -       -      +
    503A  THR      3.2     0.4    -      -       -      -
    504A  ILE*     1.3    75.3    -      -       -      +
    506A  LEU*     1.3    60.5    +      -       -      +
    508A  ALA*     2.9     3.9    +      -       +      +
    509A  LYS*     2.9    49.6    +      -       +      +
----------------------------------------------------------
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Residues in contact with LEU 506 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    310A  PHE*     4.8     9.9    -      -       +      -
    364A  VAL      4.0    17.0    -      -       -      +
    365A  MET*     4.0    30.7    -      -       +      -
    502A  SER      3.1    17.2    +      -       -      +
    503A  THR*     3.8    13.7    -      -       +      +
    504A  ILE      3.3     0.2    -      -       -      -
    505A  TRP*     1.3    79.9    -      -       -      +
    507A  LEU*     1.3    56.2    +      -       +      +
    509A  LYS*     3.7    30.3    +      -       +      +
    510A  ALA*     3.0    26.3    +      -       -      +
    756A  PRO*     5.6     3.6    -      -       +      +
    760A  TYR*     3.7    31.4    -      -       +      +
----------------------------------------------------------
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Residues in contact with LEU 507 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    503A  THR*     3.0    29.4    +      -       +      +
    504A  ILE*     3.9     4.5    -      -       -      +
    505A  TRP      3.2     0.2    -      -       -      -
    506A  LEU*     1.3    77.8    -      -       +      +
    508A  ALA*     1.3    54.9    +      -       -      +
    510A  ALA*     3.6     6.7    -      -       +      +
    511A  HIS*     3.2    31.9    +      -       -      -
    739A  ARG*     3.4    19.1    -      -       -      +
    741A  ILE*     3.7    15.9    -      -       +      -
    742A  PRO*     4.1     3.6    -      -       +      -
    752A  MET*     3.5    32.5    -      -       +      -
    756A  PRO      5.5     1.1    -      -       -      +
    759A  ALA*     3.5    11.4    -      -       +      +
    760A  TYR*     3.8    21.3    -      -       +      -
    763A  THR*     3.3    27.6    -      -       -      +
----------------------------------------------------------
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Residues in contact with ALA 508 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    474A  ILE*     3.8    21.6    -      -       +      +
    476A  LEU*     4.3    12.1    -      -       +      +
    493A  VAL*     3.9    27.4    -      -       +      -
    504A  ILE      3.1    13.7    +      -       -      +
    505A  TRP*     2.9    11.0    +      -       +      +
    507A  LEU*     1.3    71.1    -      -       -      +
    509A  LYS*     1.3    66.7    +      -       -      +
    510A  ALA      3.2     1.1    -      -       -      -
    511A  HIS*     3.1     4.7    +      -       -      +
    512A  VAL*     3.0    26.2    +      -       -      +
    741A  ILE*     4.2     0.9    -      -       -      +
----------------------------------------------------------
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Residues in contact with LYS 509 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    364A  VAL      5.9     0.2    -      -       -      -
    365A  MET*     2.8    31.9    +      -       -      +
    366A  THR      4.5     0.2    -      -       -      -
    367A  ASP*     3.2    15.8    +      -       -      +
    370A  PHE*     4.0    35.4    -      -       +      -
    474A  ILE*     3.5    21.5    -      -       +      +
    505A  TRP*     2.9    41.8    +      -       +      +
    506A  LEU*     3.8    24.4    -      -       +      +
    508A  ALA*     1.3    74.7    -      -       -      +
    510A  ALA*     1.3    61.1    +      -       -      +
    512A  VAL*     3.4     4.6    -      -       -      +
    513A  ILE*     3.1    29.8    +      -       +      +
----------------------------------------------------------
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Residues in contact with ALA 510 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    506A  LEU      3.0    18.9    +      -       -      +
    507A  LEU*     3.6     9.9    -      -       -      +
    509A  LYS*     1.3    75.7    -      -       -      +
    511A  HIS*     1.3    61.0    +      -       -      +
    513A  ILE*     3.4     2.3    +      -       -      -
    514A  VAL*     3.1    27.5    +      -       -      +
    734A  PRO*     3.8    10.7    -      -       +      +
    760A  TYR*     3.8    26.2    -      -       +      +
    763A  THR*     5.2     5.6    -      -       +      -
    764A  ILE*     4.3    14.8    -      -       +      -
----------------------------------------------------------
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Residues in contact with HIS 511 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    453A  LYS      3.7     9.6    -      -       -      -
    454A  ALA*     4.8     0.2    -      -       -      +
    455A  TYR*     3.5    36.5    +      +       +      +
    457A  THR*     4.0     5.2    -      -       +      -
    476A  LEU*     3.8    17.9    -      -       +      -
    507A  LEU      3.2    21.6    +      -       -      -
    508A  ALA      3.1     8.7    +      -       -      +
    510A  ALA*     1.3    74.1    -      -       -      +
    512A  VAL*     1.3    65.4    +      -       -      +
    514A  VAL*     3.0    19.9    +      -       -      +
    515A  ASN*     3.3    12.1    +      -       -      -
    737A  ALA*     3.5    32.0    -      -       +      +
    739A  ARG*     3.2    27.0    +      -       -      -
    740A  PHE*     4.6     2.2    -      -       -      -
    741A  ILE*     4.5     7.9    -      -       +      -
    763A  THR*     3.5    13.7    -      -       +      +
----------------------------------------------------------
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Residues in contact with VAL 512 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    370A  PHE*     3.9    17.5    -      -       +      -
    433A  LEU*     4.0    18.8    -      -       +      +
    435A  TYR*     4.4     1.5    -      -       +      -
    457A  THR*     3.5    22.7    +      -       -      +
    459A  THR*     3.3    21.1    -      -       -      +
    474A  ILE*     3.3    32.3    -      -       +      -
    508A  ALA      3.0    16.4    +      -       -      +
    509A  LYS*     3.4     8.7    -      -       -      +
    511A  HIS*     1.3    74.4    -      -       -      +
    513A  ILE*     1.3    58.2    +      -       +      +
    515A  ASN*     3.5     5.9    -      -       -      +
    516A  ASP*     3.1    23.2    +      -       -      +
----------------------------------------------------------
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Residues in contact with ILE 513 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    370A  PHE*     3.6    34.1    -      -       +      +
    374A  VAL*     6.0     2.9    -      -       +      -
    433A  LEU*     5.5     2.7    -      -       +      -
    509A  LYS*     3.1    18.3    +      -       +      +
    510A  ALA*     3.8     4.7    -      -       -      +
    512A  VAL*     1.3    76.7    -      -       +      +
    514A  VAL*     1.3    59.9    +      -       -      +
    516A  ASP*     3.8    16.6    -      -       +      -
    517A  SER*     2.8    31.4    +      -       -      -
    732A  ASN      3.6    24.2    -      -       -      +
    733A  ARG*     3.6    34.5    -      -       -      +
    734A  PRO*     3.1     9.4    -      -       +      +
----------------------------------------------------------
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Residues in contact with VAL 514 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    454A  ALA*     5.3     0.2    -      -       +      -
    510A  ALA      3.1    17.9    -      -       -      +
    511A  HIS      3.0     9.5    +      -       -      +
    513A  ILE*     1.3    74.2    -      -       -      +
    515A  ASN*     1.4    64.8    +      -       -      +
    517A  SER*     3.5     2.1    +      -       -      -
    518A  GLY*     3.0    20.4    +      -       -      -
    584A  LEU*     3.7    22.6    -      -       +      +
    734A  PRO*     3.6    22.2    -      -       +      +
    735A  THR      3.5    20.0    -      -       -      +
    736A  LEU      3.8    16.4    -      -       -      +
    737A  ALA*     3.6    32.1    -      -       +      +
    764A  ILE*     5.4     2.5    -      -       +      -
----------------------------------------------------------
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Residues in contact with ASN 515 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    435A  TYR*     3.6    17.7    -      -       +      +
    439A  PHE*     3.5    35.3    -      -       +      -
    454A  ALA*     5.2     0.4    -      -       -      +
    455A  TYR      2.8    23.3    +      -       -      +
    456A  ALA*     3.7     1.4    -      -       -      -
    457A  THR*     2.8    38.8    +      -       -      +
    511A  HIS*     3.3     9.8    +      -       -      -
    512A  VAL      3.5     7.2    -      -       -      +
    514A  VAL*     1.4    73.5    -      -       -      +
    516A  ASP*     1.4    52.2    +      -       -      +
    518A  GLY*     3.1     3.3    +      -       -      -
    519A  TYR*     2.8    34.1    +      -       -      +
    584A  LEU*     4.4     8.1    -      -       -      +
----------------------------------------------------------
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Residues in contact with ASP 516 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    374A  VAL*     5.6     1.9    -      -       -      +
    379A  ASN*     3.3    19.7    +      -       -      +
    433A  LEU*     3.6    18.0    -      -       +      +
    435A  TYR*     3.1    32.8    +      -       +      -
    512A  VAL      3.1    13.6    +      -       -      +
    513A  ILE*     3.8    18.3    -      -       +      +
    515A  ASN*     1.4    74.9    -      -       -      +
    517A  SER*     1.3    59.7    +      -       -      +
    519A  TYR*     3.8     0.5    -      -       -      +
    520A  HIS*     2.8    26.9    +      -       -      +
    733A  ARG*     2.6    27.6    +      -       -      +
----------------------------------------------------------
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Residues in contact with SER 517 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    513A  ILE*     2.8    24.6    +      -       -      +
    514A  VAL      3.8     2.5    -      -       -      -
    516A  ASP*     1.3    73.0    -      -       -      +
    518A  GLY*     1.3    64.7    +      -       -      +
    520A  HIS*     4.0     3.6    +      -       -      +
    521A  GLN*     3.2    24.9    +      -       -      +
    583A  PHE*     3.6    18.6    -      -       -      -
    733A  ARG*     3.0    33.2    +      -       -      +
    734A  PRO      3.1    17.1    +      -       -      -
    735A  THR*     4.4     6.2    -      -       -      +
----------------------------------------------------------
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Residues in contact with GLY 518 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    439A  PHE*     4.9     4.7    -      -       -      -
    514A  VAL      3.0    14.4    +      -       -      -
    515A  ASN      3.1     4.7    +      -       -      -
    517A  SER*     1.3    75.5    -      -       -      +
    519A  TYR*     1.3    62.6    +      -       -      +
    521A  GLN*     3.8     0.5    -      -       -      +
    522A  LEU*     3.1    41.6    +      -       -      +
    583A  PHE*     4.2    15.5    -      -       -      -
    584A  LEU*     5.5     1.1    -      -       -      -
    585A  PRO*     4.9     7.4    -      -       -      -
----------------------------------------------------------
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Residues in contact with TYR 519 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    379A  ASN*     4.1     1.3    -      -       -      -
    382A  VAL*     3.6    29.0    -      -       +      +
    435A  TYR*     3.6    40.6    -      +       +      +
    438A  ALA*     4.4    20.0    -      -       +      -
    439A  PHE*     4.6     7.6    -      +       +      -
    515A  ASN      2.8    15.8    +      -       -      +
    516A  ASP      3.8     0.7    -      -       -      +
    518A  GLY*     1.3    73.0    -      -       -      +
    520A  HIS*     1.3    58.8    +      -       -      +
    522A  LEU*     5.0     0.9    -      -       -      -
    523A  VAL*     2.7    70.1    +      -       +      +
    524A  SER*     3.1    13.8    +      -       -      -
    592A  MET*     5.9     4.5    -      -       -      -
    596A  VAL*     4.4    12.7    -      -       +      +
----------------------------------------------------------
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Residues in contact with HIS 520 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    378A  VAL*     3.2    32.6    +      -       +      +
    379A  ASN*     3.6    24.9    -      -       +      -
    516A  ASP      2.8    22.9    +      -       -      +
    517A  SER*     4.0     6.8    +      -       -      +
    519A  TYR*     1.3    72.3    -      -       -      +
    521A  GLN*     1.3    63.7    +      -       -      +
    524A  SER*     3.2    15.8    +      -       -      -
    525A  HIS*     2.7    38.2    +      -       +      +
    719A  VAL*     2.8    34.3    +      -       +      +
    723A  GLN*     3.9    26.2    +      -       +      -
    733A  ARG*     4.5     6.3    +      -       -      +
----------------------------------------------------------
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Residues in contact with GLN 521 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    517A  SER      3.2    16.2    +      -       -      +
    518A  GLY      3.8     2.9    -      -       -      +
    520A  HIS*     1.3    82.7    +      -       -      +
    522A  LEU*     1.3    55.8    +      -       +      +
    525A  HIS*     3.6    21.2    +      -       -      +
    526A  TRP*     2.7    39.3    +      -       +      +
    573A  ILE*     6.4     0.2    -      -       +      -
    579A  ILE*     3.8    34.3    -      -       +      +
    583A  PHE*     3.6    34.6    -      -       +      -
    723A  GLN*     2.9    28.9    +      -       -      +
    777A  ILE*     4.8     4.2    -      -       -      +
    780A  LEU*     4.6     6.1    -      -       -      +
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Residues in contact with LEU 522 (chain A). Click here for Legend to table.
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                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
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    518A  GLY*     3.1    24.6    +      -       -      +
    519A  TYR*     5.1     0.4    -      -       -      -
    521A  GLN*     1.3    75.8    -      -       +      +
    523A  VAL*     1.3    64.8    +      -       +      +
    526A  TRP*     3.6     8.6    -      -       +      +
    527A  LEU*     3.1    25.3    +      -       -      +
    573A  ILE*     5.5     1.1    -      -       +      -
    579A  ILE*     3.7    21.8    -      -       +      -
    583A  PHE*     5.5     2.7    -      -       +      -
    585A  PRO*     4.1    25.1    -      -       +      -
    589A  SER*     3.5    41.5    -      -       -      +
    590A  ILE*     4.0     9.2    -      -       +      -
    592A  MET*     4.5    11.9    -      -       +      -
    593A  SER*     3.6    18.7    -      -       -      +
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Residues in contact with VAL 523 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
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    519A  TYR*     2.7    55.1    +      -       +      +
    521A  GLN      3.5     0.2    -      -       -      -
    522A  LEU*     1.3    83.3    -      -       +      +
    524A  SER*     1.3    65.8    +      -       -      +
    525A  HIS      3.2     1.1    -      -       -      -
    527A  LEU*     4.1     5.4    -      -       +      -
    528A  ASN*     3.0    48.2    +      -       -      +
    592A  MET*     5.6     3.4    -      -       +      -
    593A  SER*     4.8     4.7    -      -       -      -
    596A  VAL*     3.5    39.3    -      -       +      -
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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
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  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) +   -    +    +   +   +    +    -
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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