Osmoprotection of Bacillus subtilis through Import and Proteolysis of Proline-Containing Peptides

• DOI: 10.1128/aem.01934-12
• Publication Date: 2012-11-11T01:45:04Z
• Authors: Adrienne Zaprasis; Jeanette Brill; Marietta Thüring; Guido Wünsche; Magnus Heun; Helena Barzantny; Tamara Hoffmann; Erhard Bremer
• Keywords: Osmotic shock; Tripeptide; Osmotic concentration

Bacillus subtilis can attain cellular protection against the detrimental effects of high osmolarity through osmotically induced de novo synthesis and uptake compatible solute l-proline. We have now found that B. also exploit exogenously provided proline-containing peptides various lengths compositions as osmoprotectants. Osmoprotection by these types is generally dependent on their import via peptide transport systems (Dpp, Opp, App, DtpT) operating in relies hydrolysis to liberate proline. The effectiveness with which confer osmoprotection varies considerably, this be correlated amount liberated subsequently accumulated free proline stressed cell. Through gene disruption experiments, growth studies, quantification intracellular pool, we identified PapA (YqhT) PapB (YkvY) peptidases responsible for Xaa-Pro dipeptides Xaa-Pro-Xaa tripeptides. possess overlapping substrate specificities. In contrast, a residue positioned at N terminus was not affected defects peptidases. Taken together, our data provide new insight into physiology osmotic stress response subtilis. They illustrate flexibility ubiquitously distributed microorganism effectively environmental resources its acclimatization sustained high-osmolarity surroundings accumulation solutes.