tailieunhanh - Báo cáo khoa học: Direct CIII–HflB interaction is responsible for the inhibition of the HflB (FtsH)-mediated proteolysis of Escherichia coli r32 by kCIII

The CIII protein of bacteriophage lambda exhibits antiproteolytic activity against the ubiquitous metalloprotease HflB (FtsH) of Escherichia coli, thereby stabilizing the kCII protein and promoting lysogenic development of the phage. CIII also protectsE. colir 32 , another substrate of HflB. | ỊFEBS Journal Direct CIII-HfIB interaction is responsible for the inhibition of the HfIB FtsH -mediated proteolysis of Escherichia coli Ơ32 by kCIII Sabyasachi Halder1 Subhamoy Banerjee1 2 and Pradeep Parrack1 1 Department of Biochemistry Bose Institute Kolkata India 2 Madhav Institute of Technology Science Gwalior India Keywords antiproteolytic activity heat shock lysogeny kCII r Correspondence P. Parrack Department of Biochemistry Bose Institute P-1 12 . Scheme VIIM Kolkata 700 054 India Fax 91 33 2355 3886 Tel 91 33 2569 3227 E-mail pradeep@ Received 28 April2008 revised 14 July 2008 accepted 28 July 2008 The CIII protein of bacteriophage lambda exhibits antiproteolytic activity against the ubiquitous metalloprotease HflB FtsH of Escherichia coli thereby stabilizing the kCII protein and promoting lysogenic development of the phage. CIII also protects E. coli r32 another substrate of HflB. We have recently shown that the protection of CII from HflB by CIII involves direct CIII-HflB binding without any interaction between CII and CIII Halder S Datta AB Parrack P 2007 J Bacteriol 189 8130-8138 . Such a mode of action for kCIII would be independent of the HflB substrate. In this study we tested the ability of CIII to protect r32 from HflB digestion. The inhibition of HflB-mediated proteolysis of r32 by CIII is very similar to that of kCII characterized by an enhanced protection by the core CIII peptide CIIIC amino acids 14-41 of kCIII and a lack of interaction between r32 and CIII. doi Development of the temperate coliphage k depends on a set of phage-specified regulatory proteins that interact with host target proteins 1-4 . Among several effects on host protein synthesis k provokes the overproduction of some bacterial proteins induced in the heat shock response. This effect depends on early gene expression encoded by the leftward pL transcription unit of k 5 6 . CIII is a .-specific regulatory protein from