Crystallographic Information Framework

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Index

Macromolecular dictionary (mmCIF) version 2.0.09

Category STRUCT_SHEET_TOPOLOGY

Name:
'struct_sheet_topology'

Description:

   Data items in the STRUCT_SHEET_TOPOLOGY category record details
   about the topology of the residue ranges that form a beta-sheet.
   All topology links are pairwise and the specified pairs are
   assumed to be successive in the amino-acid sequence. These
   data items are useful in describing various simple and complex
   folds, but they become inadequate when the strands in the sheet
   come from more than one chain. The
   STRUCT_SHEET_ORDER data items can be used to describe
   single- and multiple-chain-containing sheets.

Examples:

Example 1 - simple beta-barrel. 
 
    loop_
    _struct_sheet_topology.sheet_id
    _struct_sheet_topology.range_id_1
    _struct_sheet_topology.range_id_2
    _struct_sheet_topology.offset
    _struct_sheet_topology.sense
     sheet_1  strand_a  strand_b  +1  parallel
     sheet_1  strand_b  strand_c  +1  parallel
     sheet_1  strand_c  strand_d  +1  parallel
     sheet_1  strand_d  strand_e  +1  parallel
     sheet_1  strand_e  strand_f  +1  parallel
     sheet_1  strand_f  strand_g  +1  parallel
     sheet_1  strand_g  strand_h  +1  parallel
     sheet_1  strand_h  strand_a  +1  parallel


Example 2 - five stranded mixed-sense sheet with one two-piece strand. 
 
    loop_
    _struct_sheet_topology.sheet_id
    _struct_sheet_topology.range_id_1
    _struct_sheet_topology.range_id_2
    _struct_sheet_topology.offset
    _struct_sheet_topology.sense
     sheet_2  strand_a   strand_c    +2 anti-parallel
     sheet_2  strand_c   strand_d1   +1 anti-parallel
     sheet_2  strand_d1  strand_e    +1 anti-parallel
     sheet_2  strand_e   strand_d2   -1 anti-parallel
     sheet_2  strand_d2  strand_b    -2 anti-parallel


Category groups:
    inclusive_group
    struct_group
Category keys:
    _struct_sheet_topology.sheet_id
    _struct_sheet_topology.range_id_1
    _struct_sheet_topology.range_id_2

Mandatory category: no


International Tables for Crystallography

Volume G: Definition and exchange of crystallographic data

First online edition (2006)

Edited by S. R. Hall and B. McMahon

An essential guide and reference to CIF for programmers, data managers handling crystal-structure information and practising crystallographers.