wwPDB: File Format

PDB File Format - Contents Guide Version 3.20 (September 15, 2008)
PDF - US Letter PDF - A4 HTML
PDB File Format - Contents Guide Version 3.1 (July 19, 2007)
PDF
PDB File Format - Contents Guide Version 3.0 (December 01, 2006)
PDF HTML
PDB File Format - Contents Guide Version 2.3 (July 09, 1998)
PDF - US Letter PDF - A4 HTML
The original Protein Data Bank Contents Guides were developed by the Protein Data Bank team at Brookhaven National laboratory. Historical copies are available.
PDF - 1972 PDF - 1976 PDF - 1978 PDF - 1985 PDF - 1989 PDF - 1992

PDF - Jan 1996 PDF - Feb 1996 PDF - Aug 1996 PDF - Oct 1996 PDF - Dec 1996
The original PDB format was introduced in 1972 and used a line length of 132 characters plus 8 for sequencing. In 1976, a version using 72 characters plus 8 for sequencing was introduced. This 80-column format is what has commonly been called the (legacy) "PDB format". Many details were changed based on experience, with the major change from supporting both orthogonal and fractional coordinates to only orthogonal coordinates. From 1976 - 1977, new entries were processed and older entries reprocessed using the 1976 format.