Miscellaneous Features Section

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

SITE

Overview

The SITE records supply the identification of groups comprising important sites in the macromolecule.

Record Format

COLUMNS       DATA TYPE         FIELD            DEFINITION
------------------------------------------------------------------------
 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 comprising 
                                            site.
19 - 21       Residue name      resName1    Residue name for first residue
                                            comprising site.
23            Character         chainID1    Chain identifier for first residue
                                            comprising site.
24 - 27       Integer           seq1        Residue sequence number for first
                                            residue comprising site.
28            AChar             iCode1      Insertion code for first residue
                                            comprising site.
30 - 32       Residue name      resName2    Residue name for second residue
                                            comprising site.
34            Character         chainID2    Chain identifier for second 
                                            residue
                                            comprising site.
35 - 38       Integer           seq2        Residue sequence number for second
                                            residue comprising site.
39            AChar             iCode2      Insertion code for second residue
                                            comprising site.
41 - 43       Residue name      resName3    Residue name for third residue
                                            comprising site.
45            Character         chainID3    Chain identifier for third residue
                                            comprising site.
46 - 49       Integer           seq3        Residue sequence number for third
                                            residue comprising site.
50            AChar             iCode3      Insertion code for third residue
                                            comprising site.
52 - 54       Residue name      resName4    Residue name for fourth residue
                                            comprising site.
56            Character         chainID4    Chain identifier for fourth 
                                            residue
                                            comprising site.
57 - 60       Integer           seq4        Residue sequence number for fourth
                                            residue comprising site.
61            AChar             iCode4      Insertion code for fourth residue
                                            comprising site.

Details

Site records specify residues comprising catalytic, cofactor, anticodon, regulatory or other important sites or environments surrounding ligands present in the structure.

The sequence number (columns 8 - 10) is reset to 1 for each new site.

SITE identifiers (columns 12 - 14) should be fully explained in a remark.

If a site is comprised 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 remark that describes it. 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            
1234567890123456789012345678901234567890123456789012345678901234567890            
SITE     1 DTA  3 ASP A  25  THR A  26  GLY A  27         
SITE     1 DTB  3 ASP B  25  THR B  26  GLY B  27         
SITE     1   A  4   U A  44    C A  46    G A  61    U A 118
SITE     1 ZN1  5 CYS A  97  CYS A 100  CYS A 103  CYS 1 111 
SITE     2 ZN1  5  ZN A 375

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