Salmonella Research Today is a free monthly online journal that collates and summarizes the latest research about Salmonella, including details on salmonella typhimurium, food poisoning, infection, treatment.

Characterization and role of Peptidase N from Salmonella enterica serovar Typhimurium.

Kumar A, Nandi D

Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.

ATP-independent peptidases are important during the distal steps of cytosolic protein degradation. The contribution of a member of this group, Peptidase N (PepN) was studied in Salmonella enterica serovar Typhimurium (Salmonella typhimurium). The DeltapepN strain displays greatly reduced cleavage of 9 out of a total of 13 exopeptidase substrates, demonstrating a significant contribution of PepN to cytosolic aminopeptidase activity. The cleavage profile of purified S. typhimurium PepN is Arg>Ala>Thr, demonstrating broad specificity. Comparative biochemical studies with purified PepN from Escherichia coli and S. typhimurium revealed the latter to be distinct: S. typhimurium PepN cleaves Thr-AMC more efficiently and is less sensitive to inhibition by N-ethylmaleimide. Studies with DeltapepN and PepN overexpression demonstrated its importance for growth during nutritional downshift in combination with high temperature stress. In summary, S. typhimurium PepN contributes significantly to cytosolic aminopeptidase activity and its role is manifested under selected stress conditions.

Published 12 January 2007 in Biochem Biophys Res Commun, 353(3): 706-12.
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