Protein Structure Initiative

A complete understanding of protein function and evolution requires information about both protein sequence and 3D structure, thus the Protein Structure Initiative (PSI) was established in 2000 by the National Institutes of General Medical Sciences with the long-term goal of providing 3D structural information for most proteins in nature.

First came a pilot phase to test the feasibility and develop the methodology. A 2nd phase was to solve large numbers of structures using insights from the first phase and the 3rd phase aims  to expand the role of the 3D structure in biological research.

One operational metric of the program is a count of 3D structures of ‘distinct’ proteins (or domains), referred to as ‘Distinct Structures’, deposited into the Protein Data Bank (PDB). By 2005 deposits of more than 3,000 Distinct Structures into the PDB and by 2011 there were 5,000 3D protein structures.

Many include protein domain families of structures - a ‘protein domain family’ is a set of homologous protein domains likely to have similar structures and possibly similar biochemical functions and that may be used as models of thousands of homologous proteins.  This PSI structural database is also being used for testing new methods for protein structure prediction and automated data analysis.

The PDB information on protein 3D structures is available to the broad biological community in an “open source” fashion, in which intermediate results, protein expression systems and protocols, protein structures, and new technologies are made available to the community as soon as the  data and/or methods are deemed to be reliable.

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