Navigating the Brookhaven Protein Data Bank

The Protein Data Bank maintained at Brookhaven National Laboratories has expanded to the point where even experienced users have difficulty understanding, exploring, and exploiting it. This paper describes a text file, an annotation of the Protein Data Bank, which helps users find information on related files and structures. The most recent version of this file includes information on homologous structures, including both sequence homology and structural homology. This file is in ASCII format and is available electronically. It is easy to search locally on any type of computer, using an editor or a pattern-matching program, such as grep.