The argC gene product (351 amino acids) of A. brasilense shared high similarity with the ArgC protein

of R. centenum, M. magneticum and R. rubrum. The N-acetyl-gamma-glutamate-phosphate reductase (EC 1.2.1.38) encoded by 4SC-202 mw argC is involved in the arginine biosynthesis in prokaryotes [15]. The arginine biosynthetic pathway proceeds via N-acetylation of L-glutamate by N-acetylglutamate synthase (ArgA) yielding N-acetylglutamate which is converted into N-acetylglutamyl-phosphate by N-acetylglutamate 5-phosphoAPR-246 price transferase encoded by argB. N-acetylglutamyl-phosphate is subsequently reduced to N-acetylglutamic semialdehyde by N-acetylglutamyl-phosphate reductase, encoded by the argC gene. Thus the ArgC protein catalyses the third step in the pathway of biosynthesis of arginine from glutamate [15]. Figure 4 Schematic representation of the genomic organization of gene predicted to encode γ-CA in Azospirillum brasilense and other closely related α-proteobacteria sharing highest similarity for γ-CA sequences. Arrows indicate the positions and orientations of the potential ORFs predicted

to encode γ-CA (black), N-acetyl-gamma-glutamyl phosphate reductase (gray), hypothetical proteins (lined) and other known Selleckchem CP673451 proteins (white). 1. 50 S ribosomal protein; 2. 30 S ribosomal protein; 3. OmpA/MotB domain protein precursor; 4. Poly(3-hydroxyalkanoate) synthase; 5. phosphoribosyl AMP cyclohydrolase; 6. cystathionine beta lyase; 7. Acetyltransferase (GNAT family); 8. poly-beta hydroxybutyrate transferase; 9. Arylsulphatase regulator; 10. Aminotransferase; 11. ABC transporter component; 12. Binding protein dependent transport systems inner Parvulin membrane component. Several studies have shown that short intergenic distance between ORFs and phylogenetically conserved gene order are important generalized predictor of operon structure [16]. Thus, conservation of this adjacent, co-directional gene-pair might link apparently unrelated argC and gca1 genes in a co-transcriptional relationship. In order

to test this possibility, the chromosomal neighbourhoods of gca1 orthologs in sequenced bacterial genomes of the members of phylogenetic tree (Figure 1) including both distant and close relatives of A. brasilense were analyzed. Interestingly, this gene order was found to be fairly well conserved in some of the sequenced members of Rhodobacteriaceae such as M. magneticum, R. rubrum and R. centenum (Figure 4). A similar syntenic organization was also observed in a member of Acetobacteriaceae (Granulibacter bethesdensis), but not in other bacterial genomes in which gca1 homologs are found. Examination of the intergenic distance between argC and γ-CA encoding genes revealed a distance of only 8 nt in M. magneticum and G. bethesdensis, 35 nt in A.