Escherichia coli HflK and HflC can individually inhibit the HflB (FtsH)-mediated proteolysis of λCII in vitro
详细信息 查看全文
- 作者：Kaustav B ; yopadhyay ; Pabitra Kumar Parua ; Ajit Bikram Datta ; Pradeep Parrack
- 关键词：Lysis– ; lysogeny decision ; HflA ; λ ; CII
- 刊名：Archives of Biochemistry and Biophysics
- 出版年：2010
- 出版时间：15 September 2010
- 年：2010
- 卷：501
- 期：2
- 页码：239-243
- 全文大小：576 K
文摘
λCII is the key protein that influences the lysis/lysogeny decision of λ by activating several phage promoters. The effect of CII is modulated by a number of phage and host proteins including Escherichia coli HflK and HflC. These membrane proteins copurify as a tightly bound complex ‘HflKC’ that inhibits the HflB (FtsH)-mediated proteolysis of CII both in vitro and in vivo. Individual purification of HflK and HflC has not been possible so far, since each requires the presence of the other for proper folding. We report the first purification of HflK and HflC separately as active and functional proteins and show that each can interact with HflB on its own and each inhibits the proteolysis of CII. They also inhibit the proteolysis of E. coli σ32 by HflB. We show that at low concentrations each protein is dimeric, based on which we propose a scheme for the mutual interactions of HflB, HflK and HflC in a supramolecular HflBKC protease complex.