A data bank merging related protein structures and sequences

A data collection which merges protein structural and sequence information is described. Structural superpositions amongst proteins with similar main-chain fold were performed or collected from the literature. Sequences taken from the protein primary structure databases were associated with the multiple structural alignments providing they were at least 50% homologous in residue identity to one of the structural sequences and at least 50% of the structural sequence residues were alignable. Such restrictions allow reasonable confidence that the primary sequences share the conformation of the tertiary structural templates, except in the less conserved loop regions. Multiple structural superpositions were collected for 38 familial groups containing a total of 209 tertiary structures; 45 structures had no superposable mates and were used individually. Other information is also provided as main-chain and side-chain conformational angles, secondary structural assignments and the like. Wedding the primary and tertiary structural data resulted in an 8-fold increase of data bank sequence entries over those associated with the known three-dimensional architectures alone.