tailieunhanh - Báo cáo khoa học: Enzymatic investigation of the Staphylococcus aureus type I signal peptidase SpsB – implications for the search for novel antibiotics
Staphylococcus aureushas one essential type I signal peptidase (SPase), SpsB, which has emerged as a potential target in the search for antibiotics with a new mode of action. In this framework, the biochemical properties of SpsB are described and compared with other previously characterized SPases. | Enzymatic investigation of the Staphylococcus aureus type I signal peptidase SpsB - implications for the search for novel antibiotics Smitha Rao Katrijn Bockstael2 Sangeeta Nath3 Yves Engelborghs3 Jozef Anne1 and Nick Geukens 1 Laboratory of Bacteriology Katholieke Universiteit Leuven Belgium 2 Laboratory for MedicinalChemistry Katholieke Universiteit Leuven Belgium 3 Laboratory of Biomolecular Dynamics Katholieke Universiteit Leuven Belgium Keywords arylomycin IsaA signalpeptidase SpsB Staphylococcus aureus Correspondence J. Anne Laboratory of Bacteriology Rega Institute for MedicalResearch Katholieke Universiteit Leuven Minderbroedersstraat 10 3000 Leuven Belgium Fax 32 16 337 340 Tel 32 16 337 371 E-mail Website http bacteriology Present address PharmAbs Katholieke Universiteit Leuven Antibody Center Belgium Received 11 July 2008 revised 10 March 2009 accepted 3 April 2009 doi Staphylococcus aureus has one essential type I signal peptidase SPase SpsB which has emerged as a potential target in the search for antibiotics with a new mode of action. In this framework the biochemical properties of SpsB are described and compared with other previously characterized SPases. Two different substrates have been used to assess the in vitro processing activity of SpsB a a native preprotein substrate immunodominant staphylococcal antigen A and b an intramolecularly quenched fluorogenic synthetic peptide based on the sequence of the SceD preprotein of Staphylococcus epidermidis for fluorescence resonance energy transfer-based analysis. Activity testing at different pH showed that the enzyme has an optimum pH of approximately 8. The pH-rate profile revealed apparent pKa values of and . Similar to the other SPases SpsB undergoes self-cleavage and although the catalytic serine is retained in the self-cleavage product a very low residual enzymatic activity remained. In contrast a truncated .
đang nạp các trang xem trước