Miscellaneous Features Section

The miscellaneous features section may describe properties in the molecule such as environments surrounding a non-standard residue or the assembly of an active site. Other features may be described in the remarks section but are not given a specific record type so far.

SITE

Overview

Site records specify residues comprising catalytic, co-factor, anti-codon, regulatory or other essential sites or environments surrounding ligands present in the structure.

Record Format

COLUMNS DATA TYPE FIELD DEFINITION
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1 - 6 Record name "SITE "
8 - 10 Integer seqNum Sequence number.
12 - 14 LString(3) siteID Site name.
16 - 17 Integer numRes Number of residues that compose the site.
19 - 21 Residue name resName1 Residue name for first residue that
creates the site.
23 Character chainID1 Chain identifier for first residue of site.
24 - 27 Integer seq1 Residue sequence number for first residue
of the site.
28 AChar iCode1 Insertion code for first residue of the site.
30 - 32 Residue name resName2 Residue name for second residue that
creates the site.
34 Character chainID2 Chain identifier for second residue of
the site.
35 - 38 Integer seq2 Residue sequence number for second
residue of the site.
39 AChar iCode2 Insertion code for second residue
of the site.
41 - 43 Residue name resName3 Residue name for third residue that
creates the site.
45 Character chainID3 Chain identifier for third residue
of the site.
46 - 49 Integer seq3 Residue sequence number for third
residue of the site.
50 AChar iCode3 Insertion code for third residue
of the site.
52 - 54 Residue name resName4 Residue name for fourth residue that
creates the site.
56 Character chainID4 Chain identifier for fourth residue
of the site.
57 - 60 Integer seq4 Residue sequence number for fourth
residue of the site.
61 AChar iCode4 Insertion code for fourth residue
of the site.

Details

The sequence number (columns 8 - 10) is reset to 1 for each new site.
SITE identifiers (columns 12 - 14) should be fully explained in remark 800.
If a site is composed of more than four residues, these may be specified on additional records bearing the same site identifier.
SITE records can include HET groups.

Verification/Validation/Value Authority Control

Every SITE must have a corresponding description in remark 800. The numbering of sequential SITE records and format of each one is verified, as well as the existence of each residue in the ATOM records.

Relationships to Other Record Types

Each listed SITE needs a corresponding REMARK 800 that details its significance.

Example

         1         2         3         4         5         6         7         8
12345678901234567890123456789012345678901234567890123456789012345678901234567890
SITE     1 AC1  3 HIS A  94  HIS A  96  HIS A 119                               
SITE     1 AC2  5 ASN A  62  GLY A  63  HIS A  64  HOH A 328                    
SITE     2 AC2  5 HOH A 634                                                     
SITE     1 AC3  5 GLN A 136  GLN A 137  PRO A 138  GLU A 205                    
SITE     2 AC3  5 CYS A 206                                                     
SITE     1 AC4 11 HIS A  64  HIS A  94  HIS A  96  HIS A 119                    
SITE     2 AC4 11 LEU A 198  THR A 199  THR A 200  TRP A 209                    
SITE     3 AC4 11 HOH A 572  HOH A 582  HOH A 635