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HEADLINES
No. 21 Spring 2004 FRONT PAGE Message from the RCSB PDB PDB Chemical Component Dictionary Format Description Available Validation of Protein Structures for the PDB PDB Deposition Statistics Release of New Deposition Tool at BMRB Website Statistics QuickSearch Available on RCSB PDB Site Accessing and Understanding Biological Units The PDB: A Case Study in Management of Community Data Molecular Machinery Poster Available as PDF Art of Science Exhibit Visits the University of Wisconsin-Madison Molecules of the Quarter: Carbonic Anhydrase, Glycolytic Enzymes, Calcium Pump PDB Community Focus: Helen M. Berman PDB Education Corner by Tommie S. Hata Related Links: File Formats RCSB PDB Job Listing RCSB PDB Members & Statement of Support Questions? info@rcsb.org © 2004 RCSB PDB
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Accessing And Understanding Biological Units
When crystallographic structures are deposited in the PDB, the primary coordinate file generally contains one asymmetric unit - a concept that has applicability only to crystallography, but is important to understanding the process in obtaining the functional biological molecule. An introduction to biological units in the PDB archive is now accessible at www.rcsb.org/pdb/biounit_tutorial.html. This useful guide: * Defines "asymmetric unit" and "biological molecule." * Indicates where information about the biological unit can be found in PDB and mmCIF coordinate files. * Describes how the biological unit files in the PDB have been derived. Coordinate files for the biological units for applicable structures are accessible from the View Structure and Download/Display File sections of the Structure Explorer pages on the primary PDB website and its mirrors. The biological unit coordinate files can also be downloaded from the PDB FTP site at ftp://ftp.rcsb.org/pub/pdb/data/biounit/coordinates. Images for the asymmetric and biological units are available from each entry's View Structure section of the Structure Explorer page. |
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