Contacts of the helix formed by residues 103 - 123 (chain A) in PDB entry 1XS2


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 ASN 103 (chain A).
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     64A  GLU*     4.5     7.5    +      -       -      -
     65A  GLU*     3.4    29.6    +      -       -      +
     69A  GLY*     5.2     7.5    +      -       -      -
     70A  ALA*     5.4     0.6    -      -       -      +
     73A  LEU*     3.6    33.5    -      -       +      +
     78A  PHE*     5.1     1.1    -      -       +      -
    100A  TYR*     6.5     0.4    -      -       +      -
    101A  ARG      3.0    16.6    -      -       -      +
    102A  GLY*     1.3    72.0    -      -       -      +
    104A  ARG*     1.3    64.8    +      -       -      +
    105A  MET      3.3     2.7    -      -       -      -
    106A  ALA*     3.3     3.0    +      -       +      +
    107A  ARG*     3.1    24.0    +      -       +      +
     60C  PRO*     3.6     8.4    -      -       +      +
     64C  GLU*     2.9    29.1    +      -       -      +
     66C  THR*     5.0     6.5    -      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ARG 104 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     64A  GLU*     5.2     1.2    +      -       -      +
     65A  GLU*     3.3     5.1    +      -       -      +
    102A  GLY*     4.1    16.9    -      -       -      +
    103A  ASN*     1.3    77.1    -      -       -      +
    105A  MET*     1.3    58.4    +      -       -      +
    107A  ARG*     3.3    11.8    +      -       -      +
    108A  ALA*     2.8    28.9    +      -       -      +
    249A  ALA*     3.2    32.3    +      -       -      +
    250A  SER*     3.8    15.6    -      -       -      -
    271A  ALA      3.7     2.0    -      -       -      -
    272A  ARG      3.6    19.5    -      -       -      +
    273A  VAL      2.6    30.7    +      -       -      -
    274A  GLY*     3.6    12.1    -      -       -      +
    278A  GLU*     3.9    15.8    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with MET 105 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     54A  GLY*     5.4     0.5    -      -       -      -
     55A  THR*     3.3    27.8    -      -       -      +
     56A  MET*     3.8    34.0    -      -       +      +
     62A  TYR*     3.9    33.7    -      -       +      -
     63A  ARG*     4.5    13.2    -      -       +      -
     65A  GLU*     2.9    25.1    +      -       -      +
    104A  ARG*     1.3    77.2    -      -       -      +
    106A  ALA*     1.3    62.3    +      -       -      +
    108A  ALA*     3.0    13.6    +      -       -      +
    109A  MET*     3.2    16.5    +      -       -      +
    271A  ALA*     3.4    19.1    -      -       +      +
    272A  ARG*     4.0    21.3    -      -       +      +
    298A  MET*     4.6     4.0    -      -       +      -
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 106 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     56A  MET*     3.8     8.4    -      -       -      +
     65A  GLU*     3.0    16.5    +      -       -      +
     70A  ALA*     4.0    29.2    -      -       +      +
     73A  LEU*     4.1    18.4    -      -       +      -
     74A  LEU*     3.8    12.4    -      -       +      +
     78A  PHE*     4.1     5.6    -      -       +      -
    103A  ASN*     3.7     5.4    -      -       -      +
    104A  ARG      3.3     0.2    -      -       -      -
    105A  MET*     1.3    72.5    -      -       -      +
    107A  ARG*     1.3    66.8    +      -       -      +
    109A  MET*     3.2    20.1    +      -       -      +
    110A  VAL*     3.7     3.3    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ARG 107 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     78A  PHE*     3.5    29.2    -      -       +      -
     94A  SER*     3.1    36.2    +      -       -      +
     97A  LEU*     3.5    25.2    +      -       +      +
     98A  GLY*     3.4    22.6    +      -       -      -
    100A  TYR*     3.6    16.6    +      -       -      +
    102A  GLY      3.9    17.5    -      -       -      -
    103A  ASN      3.1    12.6    +      -       -      +
    104A  ARG*     3.4    14.4    -      -       -      +
    106A  ALA*     1.3    75.7    -      -       -      +
    108A  ALA*     1.3    62.6    +      -       -      +
    110A  VAL*     3.0    15.2    +      -       -      +
    111A  GLU*     3.1    13.8    +      -       +      +
    274A  GLY*     4.5     8.1    -      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 108 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    104A  ARG      2.8    13.4    +      -       -      +
    105A  MET      3.0    11.6    +      -       -      +
    107A  ARG*     1.3    78.0    -      -       -      +
    109A  MET*     1.3    55.2    +      -       -      +
    111A  GLU*     4.4     1.3    -      -       -      -
    112A  MET*     3.0    44.7    +      -       -      +
    271A  ALA*     3.8    26.0    -      -       +      -
    274A  GLY      3.7    24.5    -      -       -      -
    275A  GLY      3.9     1.6    -      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with MET 109 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     15A  ILE*     5.7     0.2    -      -       +      -
     39A  PRO*     3.9    27.4    -      -       +      +
     40A  LEU      4.0     4.0    -      -       -      +
     41A  LEU*     3.5    32.3    -      -       +      +
     52A  ALA*     3.6     9.7    -      -       +      +
     53A  GLU      4.2     5.2    -      -       -      +
     54A  GLY*     3.5    31.2    -      -       -      +
     56A  MET*     3.8    18.2    -      -       -      +
     70A  ALA*     5.5     0.4    -      -       -      -
     71A  LEU*     4.7     5.4    -      -       +      -
     74A  LEU*     3.8    28.0    -      -       +      -
    105A  MET      3.2     9.7    +      -       -      +
    106A  ALA*     3.5     9.0    -      -       -      +
    107A  ARG      3.2     0.4    -      -       -      -
    108A  ALA*     1.3    76.9    -      -       -      +
    110A  VAL*     1.3    61.8    +      -       -      +
    112A  MET*     5.5     0.2    -      -       -      -
    113A  ALA*     3.2    25.3    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with VAL 110 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     41A  LEU*     3.8    10.8    -      -       +      -
     43A  LEU*     3.7     4.6    -      -       +      +
     74A  LEU*     3.4    29.8    -      -       +      -
     78A  PHE*     4.1    17.5    -      -       +      -
     79A  LEU*     4.8     4.0    -      -       +      -
     82A  ILE*     3.4    30.1    -      -       +      -
     93A  VAL*     3.9    15.7    -      -       +      -
     97A  LEU*     4.0    14.4    -      -       +      -
    106A  ALA      4.0     4.5    -      -       -      +
    107A  ARG      3.0     7.0    +      -       -      +
    109A  MET*     1.3    75.9    -      -       -      +
    111A  GLU*     1.3    59.2    +      -       -      +
    113A  ALA*     3.3     2.6    +      -       -      +
    114A  ALA*     2.8    30.5    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with GLU 111 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     90A  PRO*     4.6     4.8    -      -       -      +
     93A  VAL*     5.3     3.1    -      -       -      -
     94A  SER*     3.1    28.7    -      -       -      +
     97A  LEU*     5.6     1.5    -      -       +      +
    107A  ARG      3.1    12.2    +      -       -      +
    108A  ALA      4.1     1.1    -      -       -      +
    110A  VAL*     1.3    80.5    -      -       -      +
    112A  MET*     1.3    60.4    +      -       -      +
    114A  ALA*     3.3     8.7    -      -       -      +
    115A  TRP*     3.0    54.6    +      -       +      +
    274A  GLY      3.9    13.7    -      -       -      +
    275A  GLY*     3.3     9.2    -      -       -      -
    276A  HIS      2.9    21.9    +      -       -      -
    277A  ALA*     2.8    35.2    +      -       -      +
    278A  GLU      4.5     0.5    +      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with MET 112 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     52A  ALA*     3.8     9.9    -      -       +      -
     53A  GLU      5.6     6.5    -      -       -      +
    108A  ALA*     3.0    39.1    +      -       -      +
    109A  MET*     5.5     0.2    -      -       -      -
    111A  GLU*     1.3    85.7    -      -       -      +
    113A  ALA*     1.3    67.2    +      -       -      +
    114A  ALA      3.1     1.1    -      -       -      -
    115A  TRP*     3.0    11.8    +      -       -      +
    116A  ASP      3.0    10.2    +      -       -      -
    270A  VAL*     3.6    36.8    -      -       +      -
    271A  ALA*     4.6     6.1    -      -       +      -
    275A  GLY*     4.0     4.3    -      -       -      -
    276A  HIS*     3.7    17.7    -      -       +      +
    304A  GLY*     5.9     2.2    -      -       -      -
    307A  HIS*     3.4    51.2    -      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 113 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     41A  LEU*     4.1     6.5    -      -       +      +
     43A  LEU*     3.7    23.1    -      -       +      +
     50A  GLY*     3.4    19.6    -      -       -      +
     51A  VAL      4.1     8.3    -      -       -      +
     52A  ALA*     3.6    17.5    -      -       +      +
    109A  MET      3.2    19.6    +      -       -      +
    110A  VAL      3.3     3.1    +      -       -      +
    112A  MET*     1.3    76.8    -      -       -      +
    114A  ALA*     1.3    56.7    +      -       -      +
    116A  ASP      3.3     1.0    +      -       -      -
    117A  LEU*     3.0    26.2    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 114 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
      8A  PHE*     4.7     6.0    -      -       +      -
     10A  ILE*     5.5     0.4    -      -       +      -
     43A  LEU*     3.8     9.3    -      -       +      +
     90A  PRO*     4.1     8.9    -      -       +      +
     93A  VAL*     4.3    29.2    -      -       +      -
    110A  VAL      2.8    14.4    +      -       -      +
    111A  GLU*     3.3    13.9    -      -       -      +
    112A  MET      3.1     0.2    -      -       -      -
    113A  ALA*     1.3    74.7    -      -       -      +
    115A  TRP*     1.3    59.2    +      -       -      +
    117A  LEU*     3.8     7.4    -      -       -      +
    118A  TRP*     2.9    31.7    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with TRP 115 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     90A  PRO*     3.5    30.8    -      -       +      +
     91A  GLU*     3.6    27.4    -      -       -      -
    111A  GLU*     3.0    54.7    +      -       -      -
    112A  MET      3.0     7.8    +      -       -      +
    114A  ALA*     1.3    76.0    -      -       -      +
    116A  ASP*     1.3    58.0    +      -       -      +
    118A  TRP*     3.7    20.9    -      +       -      +
    119A  ALA*     2.9    32.6    +      -       -      +
    126A  LEU*     3.7    28.4    -      -       +      +
    129A  LEU*     4.2    23.1    -      -       +      -
    130A  LEU*     3.8    26.0    -      -       +      -
    276A  HIS*     3.8    16.6    -      +       +      -
    277A  ALA*     3.8    11.5    -      -       +      +
    280A  ARG*     4.8     6.3    -      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with ASP 116 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     49A  GLN      4.1     0.3    -      -       -      +
     50A  GLY*     3.5     3.1    -      -       -      -
     51A  VAL*     3.0    30.5    +      -       -      +
    112A  MET      3.0    11.6    +      -       -      +
    113A  ALA      3.5     8.5    -      -       -      +
    114A  ALA      3.2     0.2    -      -       -      -
    115A  TRP*     1.3    78.8    -      -       -      +
    117A  LEU*     1.3    57.6    +      -       -      +
    119A  ALA*     3.3     4.6    +      -       -      +
    120A  ARG*     2.6    67.4    +      -       -      +
    126A  LEU*     5.2     2.0    -      -       -      -
    307A  HIS*     4.3     2.7    -      -       +      -
    353A  GLY*     3.3     2.0    -      -       -      -
    354A  THR*     3.0    40.8    +      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with LEU 117 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
      8A  PHE*     4.1    26.7    -      -       +      -
      9A  LYS      5.1     0.4    -      -       -      +
     10A  ILE*     4.2    16.4    -      -       +      -
     43A  LEU*     4.3    16.4    -      -       +      +
     45A  GLY*     3.7    21.5    -      -       -      +
     48A  VAL*     3.2    38.8    -      -       +      +
     49A  GLN*     3.8    11.9    -      -       -      -
     50A  GLY*     3.6     8.8    -      -       -      +
    113A  ALA      3.0    16.8    +      -       -      +
    114A  ALA*     3.8     4.9    -      -       -      +
    116A  ASP*     1.3    74.2    -      -       -      +
    118A  TRP*     1.3    64.9    -      -       -      +
    120A  ARG*     3.0     5.5    +      -       -      +
    121A  THR*     2.9    28.9    +      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with TRP 118 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
      6A  ARG      3.5    25.4    -      -       -      -
      8A  PHE*     3.6    25.8    -      +       +      -
     88A  ALA      3.4    21.1    -      -       -      -
     89A  ASN*     4.4     5.4    -      -       +      +
     90A  PRO*     3.1    37.9    -      -       +      +
    114A  ALA      2.9    22.9    +      -       -      +
    115A  TRP*     3.7    19.6    -      +       -      +
    117A  LEU*     1.3    72.4    -      -       -      +
    119A  ALA*     1.3    60.9    +      -       -      +
    121A  THR*     2.5    36.0    +      -       -      -
    122A  LEU*     3.2    36.3    +      -       +      +
    129A  LEU*     3.9    19.3    -      -       +      +
----------------------------------------------------------
 Back to top of page

Residues in contact with ALA 119 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    115A  TRP      2.9    19.6    +      -       -      +
    116A  ASP*     3.5     4.5    -      -       -      +
    118A  TRP*     1.3    76.8    -      -       -      +
    120A  ARG*     1.3    57.5    +      -       -      +
    122A  LEU*     3.2     3.0    +      -       -      +
    123A  GLY      2.9     8.1    +      -       -      -
    124A  VAL      2.9    44.9    +      -       -      +
    126A  LEU*     4.5     7.6    -      -       +      -
    129A  LEU*     3.8    23.6    -      -       +      -
    353A  GLY*     3.7    12.3    -      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with ARG 120 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
     48A  VAL*     4.0    25.3    -      -       +      +
     49A  GLN*     3.2    25.6    +      -       -      +
    116A  ASP*     2.6    37.3    +      -       -      +
    117A  LEU      3.0     5.1    +      -       -      +
    119A  ALA*     1.3    74.1    -      -       -      +
    121A  THR*     1.3    62.9    +      -       -      +
    122A  LEU      3.1     2.3    +      -       -      -
    123A  GLY*     3.4     9.6    +      -       -      +
    352A  PRO*     3.3    51.0    +      -       +      +
    354A  THR*     3.2    16.8    +      -       -      -
    355A  GLY*     3.6     4.2    -      -       -      +
    356A  VAL      2.9    28.2    +      -       -      +
    357A  THR*     5.6     5.1    +      -       -      +
----------------------------------------------------------
 Back to top of page

Residues in contact with THR 121 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
      6A  ARG      5.1     2.2    +      -       -      -
      8A  PHE*     4.4    11.2    -      -       +      -
     46A  GLU*     4.3    25.1    -      -       +      -
     48A  VAL*     3.9    18.4    -      -       +      -
    117A  LEU*     2.9    19.6    +      -       +      +
    118A  TRP*     2.5    33.4    +      -       -      +
    120A  ARG*     1.3    75.5    -      -       -      +
    122A  LEU*     1.3    65.0    +      -       -      +
    123A  GLY      3.5     0.2    -      -       -      -
----------------------------------------------------------
 Back to top of page

Residues in contact with LEU 122 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
      6A  ARG      5.2    10.1    -      -       -      +
    118A  TRP*     3.2    48.7    +      -       +      +
    119A  ALA      3.2     9.1    +      -       -      +
    120A  ARG      3.1     0.6    -      -       -      -
    121A  THR*     1.3    91.4    +      -       -      +
    123A  GLY*     1.3    59.1    +      -       -      +
    124A  VAL*     3.7    17.6    +      -       +      +
    129A  LEU*     4.3    24.7    -      -       +      -
----------------------------------------------------------
 Back to top of page

Residues in contact with GLY 123 (chain A). Click here for Legend to table.
----------------------------------------------------------
                                  Specific contacts
                               ---------------------------
     Residue       Dist    Surf   HB    Arom    Phob    DC
----------------------------------------------------------
    119A  ALA      2.9     4.7    +      -       -      -
    120A  ARG      3.4    11.2    +      -       -      -
    121A  THR      3.5     0.2    -      -       -      -
    122A  LEU*     1.3    78.9    -      -       -      +
    124A  VAL*     1.3    60.5    +      -       -      +
    125A  PRO*     4.1     4.9    -      -       -      +
    352A  PRO*     4.1    17.4    -      -       -      +
----------------------------------------------------------
 Back to top of page


A short description of the analytical approach
The contact analysis used in this page is based upon the approach developed in: Sobolev V., Wade R.C., Vriend G. and Edelman M. PROTEINS (1996) 25, 120-129. Contact legitimacy depends on the hydrophobic-hydrophilic properties of the contacting atoms. In order to define it, for each inter-atomic contact, eight atom classes have been introduced:


   I  Hydrophilic      - N and O that can donate and accept hydrogen bonds
                         (e.g., oxygen of hydroxyl group of Ser. or Thr)
  II  Acceptor         - N or O that can only accept a hydrogen bond
 III  Donor            - N that can only donate a hydrogen bond
  IV  Hydrophobic      - Cl, Br, I and all C atoms that are not in
                         aromatic rings and do not have a covalent bond to
                         a N or O atom
   V  Aromatic         - C in aromatic rings irrespective of any other 
                         bonds formed by the atom
  VI  Neutral          - C atoms that have a covalent bond to at least one
                         atom of class I or two or more atoms from class II
                         or III; atoms; S, F, P, and metal atoms in all cases
 VII  Neutral-donor    - C atoms that have a covalent bond with only one
                         atom of class III
VIII  Neutral-acceptor - C atoms that have a covalent bond with only 
                         one atom of class II
For each pair of contacts the state of legitimacy is shown below:

Legend:
+, legitimate
-, illegitimate
------------------------------------------------------------
  Atomic class           I  II  III   IV   V   VI  VII  VIII
------------------------------------------------------------
   I  (Hydrophilic)      +   +    +    -   +   +    +    +
  II  (Acceptor)         +   -    +    -   +   +    +    -
 III  (Donor)            +   +    -    -   +   +    -    +
  IV  (Hydrophobic)      -   -    -    +   +   +    +    +
   V  (Aromatic)         +   +    +    +   +   +    +    +
  VI  (Neutral)          +   +    +    +   +   +    +    +
 VII  (Neutral-donor)    +   +    -    +   +   +    -    +
VIII  (Neutral-acceptor) +   -    +    +   +   +    +    -
------------------------------------------------------------
Warning!
Atom classes for heterogroups are automatically assigned based on the atomic coordinates. However, in three cases (see below) the automatic assignment is currently ambiguous. In these cases, the user is advised to manually analyse the full list of contacts using LPC software.
1. Carbon atoms belonging to a 4-, 5- or 6-member ring are 
   considered "aromatic" (Class V) if the ring is approximately
   planar, and "hydrophobic" (Class IV) or "neutral" (Classes
   VI, VII, VIII) if the ring is non-planar.
2. The oxygen atom of a carbonyl or hydroxy group is considered
   "hydroxy" (Class I) if the CO bond is longer than 1.29 Å, and
   "carbonyl" (Class II) if shorter.
3. All nitrogen atoms are considered "hydrophilic" (Class I).

Please E-mail any questions and/or suggestions concerning this page to Vladimir.Sobolev@weizmann.ac.il