Cross-species characterisation of abundantly expressed Ochrobactrum anthropi gene products

The identity of 45 protein spots representing 32 orthologues within the Och robactrum anthropi proteome within a gradient of pH 4-7, and mass range 5-9 0 kDa were determined across species boundaries. These proteins could be cl assified into 13 functional categories and establish metabolic, regulatory and translatory systems including amino acid biosynthesis, electron transpo rt and the potential for plant symbiosis in a molecularly understudied orga nism. Amino acid composition and/or peptide mass fingerprinting were employ ed as a means to search the Swiss-Prot and OWL protein sequence databases f or similarity within a broad taxonomic class of bacteria. Candidate matches from database searches could be compared and a simple multiplication matri x based on co-occurrence and rank within the top 96 most similar entries wa s used to provide statistical confidence. This mathematical matrix was eval uated with respect to the characterisation of O.anthropi, an unsequenced an d understudied bacterium, in the light of the recent influx of DNA sequence information.