Protein Data Bank
Additional recommended knowledge
Founded in 1971 by Drs. Edgar Meyer and Walter Hamilton Brookhaven National Laboratory, management of the Protein Data Bank was transferred in 1998 to members of the Research Collaboratory for Structural Bioinformatics (RCSB).
The Worldwide Protein Data Bank (wwPDB) consists of organizations that act as deposition, data processing and distribution centers for PDB data. The founding members are RCSB PDB (USA), MSD-EBI (Europe) and PDBj (Japan). The BMRB (USA) group joined the wwPDB in 2006. The mission of the wwPDB is to maintain a single Protein Data Bank Archive of macromolecular structural data that is freely and publicly available to the global community.
The PDB is a key resource in structural biology and is critical to more recent work in structural genomics.
Countless derived databases and projects have been developed to integrate and classify the PDB in terms of protein structure, protein function and protein evolution.
When the PDB was originally founded it contained just 7 protein structures. Since then it has undergone an approximate exponential growth in the number of structures, which does not show any sign of falling off.
The growth rate of the PDB has been the subject of fairly extensive analysis.
As of 26 September, 2006, the database contained 39,051 released atomic coordinate entries (or "structures"), 35,767 of that proteins, the rest being nucleic acids, nucleic acid-protein complexes, and a few other molecules. About 5,000 new structures are released each year. Data are stored in the mmCIF format specifically developed for the purpose.
Note that the database stores information about the exact location of all atoms in a large biomolecule (although, usually without the hydrogen atoms, as their positions are more of a statistical estimate); if one is only interested in sequence data, i.e. the list of amino acids making up a particular protein or the list of nucleotides making up a particular nucleic acid, the much larger databases from Swiss-Prot and the International Nucleotide Sequence Database Collaboration should be used.
As of 11 September, 2007, the "PDB Holdings List" at RCSB reported the following statistics:
Note that theoretical models are no longer accepted in the PDB.
22461 structures in the PDB have a structure factor file. 3138 structures in the PDB have an NMR restraint file.
The current breakdown of holdings is updated weekly.
Through the years the PDB file format has undergone many, many changes and revisions. Its original format was dictated by the width of computer punch cards.
This legacy format has caused many problems with the format, and consequently there are 'clean-up' projects;
The MMDB uses ASN.1 (and an XML conversion of this format). The wwPDB members RCSB PDB, MSD-EBI, and PDBj are working together to make the data uniform across the archive. Some believe this to be desirable; others argue that, without a universal repository of information (i.e., a common dictionary), it is not possible to draw comparisons.
Each structure published in PDB receives a four-character alphanumeric identifier, its PDB ID. This should not be used as an identifier for biomolecules, since often several structures for the same molecule (in different environments or conformations) are contained in PDB with different PDB IDs.
If a biologist submits structure data for a protein or nucleic acid, wwPDB staff reviews and annotates the entry. The data are then automatically checked for plausibility. The source code for this validation software has been released for free. The main data base accepts only experimentally derived structures, and not theoretically predicted ones (see protein structure prediction).
Various funding agencies and scientific journals now require scientists to submit their structure data to PDB.
Viewing the data
The structural data can be used to visualize the biomolecules with appropriate software, such as VMD, RasMol, PyMOL, Jmol, MDL Chime, QuteMol, web browser VRML plugin or any web-based software designed to visualize and analyse the protein structures such as STING. A recent desktop software addition is Sirius. The RCSB PDB website also contains resources for education, structural genomics, and related software.