PMC

(A) Definition of SSDB graph features. Circles represent protein sequences, and the features around a given sequence (shaded) are shown. Arrows indicates the relationship between the query sequence and the best-hit sequence (see text). (B) By incorporating positional coupling of genes in the genome, SSDB can be used to identify conserved gene clusters, which can then be used to create or modify an ortholog group table. Note that the KEGG ortholog group table represents an additional feature, namely functional coupling of gene products in the pathway or complex.