Extracellular Arginine Aminopeptidase from Streptococcus gordonii FSS2

Abstract

Streptococcus gordonii is a primary etiological agent in the development of subacute bacterial endocarditis (SBE), producing thrombus formation and tissue damage on the surfaces of heart valves. This is ironic, considering its normal role as a benign inhabitant of the oral microflora. However, strain FSS2 of S. gordonii has been found to produce several extracellular aminopeptidase-and fibrinogen-degrading activities during growth in a pH-controlled batch culture. In this report, we describe the purification, characterization, and partial cloning of a predicted serine class arginine aminopeptidase (RAP) with some cysteine class characteristics. Isolation of this enzyme by anion-exchange, gel filtration, and isoelectric focusing chromatography yielded a protein monomer of approximately 70 kDa, as shown by matrix-assisted laser desorption ionization, gel filtration, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis under denaturing conditions. Nested-PCR cloning enabled the isolation of a 324-bp-long DNA fragment encoding the 108-amino-acid N terminus of RAP. Culture activity profiles and N-terminal sequence analysis indicated the export of this protein from the cell surface. Homology was found with a putative dipeptidase from Streptococcus pyogenes and nonspecific dipeptidases from Lactobacillus helveticus and Lactococcus lactis. We believe that RAP may serve as a critical factor for arginine acquisition during nutrient stress in vivo and also in the proteolysis of host proteins and peptides during SBE pathology.

Regulation of Gene Expression in a Mixed-Genus Community: Stabilized Arginine Biosynthesis inStreptococcus gordoniiby Coaggregation withActinomyces naeslundii

“…Thus, S. gordonii cells may acquire arginine directly from A. naeslundii by a contact-dependent mechanism. For example, S. gordonii produces an extracellular arginine aminopeptidase (14) that could potentially scavenge arginine residues from proteins on the cell wall of A. naeslundii. However, A. naeslundii did not supply enough arginine to support the aerobic growth of an S. gordonii argH mutant in CDM containing 0.025 mM arginine (Fig.…”

Effect of Acidic pH on Expression of Surface-Associated Proteins of Streptococcus oralis

“…The gene pepV encodes a dipeptidase which is involved in the final degradation of dipeptides and which may play a role in the degradation of the milk protein casein in lactococci (16), and a homologue has also recently been identified in the culture supernatant of S. gordonii FSS2, where it may also be involved in the acquisition of small peptides (15). The dipeptidase homologue identified here in S. oralis may also be involved in the degradation and acquisition of peptides.…”

Arginine specific aminopeptidase from Lactobacillus brevis

“…However, as shown in Table 1, there were considerable amount of intracellular enzyme activity in many of them. Although there are some studies on intacellular and extracellular aminopeptidase activities (Shihata et al, 2000), several reports (El Soda et al, 1978, Kolstad andLaw, 1985) have described that aminopeptidases were intracellular enzymes that were released or leaked when the cells were lysed or damaged.Extracellular arginine aminopeptidase from Streptococcus gordonii has been reported by Goldstein et al, (2002). Miia et al, (2002).…”