Cross-species characterisation of abundantly expressed Ochrobactrum anthropi gene products.

The identity of 45 protein spots representing 32 orthologues within the Ochrobactrum anthropi proteome within a gradient of pH 4-7, and mass range 5-90 kDa were determined across species boundaries. These proteins could be classified into 13 functional categories and establish metabolic, regulatory and translatory systems including amino acid biosynthesis, electron transport and the potential for plant symbiosis in a molecularly understudied organism. Amino acid composition and/or peptide mass fingerprinting were employed as a means to search the Swiss-Prot and OWL protein sequence databases for similarity within a broad taxonomic class of bacteria. Candidate matches from database searches could be compared and a simple multiplication matrix based on co-occurrence and rank within the top 96 most similar entries was used to provide statistical confidence. This mathematical matrix was evaluated with respect to the characterisation of O. anthropi, an unsequenced and understudied bacterium, in the light of the recent influx of DNA sequence information.