tailieunhanh - Báo cáo khoa học: Small peptides derived from the Lys active fragment of the mung bean trypsin inhibitor are fully active against trypsin

Synthetic diacylglycerol lactones (DAG lactones) are effective modulators of critical cellular signaling pathways downstream of the lipophilic second messenger diacylglycerol that activate a host of protein kinase C (PKC) isozymes as well as other non-kinase proteins that share with PKC similar C1 membrane-targeting domains. | ễFEBS Journal Small peptides derived from the Lys active fragment of the mung bean trypsin inhibitor are fully active against trypsin Rui-Feng Qi1 Zhi-Xue Liu2 Shao-Qiong Xu1 Ling Zhang1 Xiao-Xia Shao1 and Cheng-Wu Chi1 2 1 Institute of Protein Research Tongji University Shanghai China 2 Institute of Biochemistry and CellBiology Chinese Academy of Sciences Shanghai China Keywords Bowman-Birk inhibitor BBI gene cloning gene expression inhibitory activity peptide synthesis Correspondence . Chi Shanghai Institute of Biochemistry and CellBiology Chinese Academy of Sciences 320 Yue Yang Road Shanghai 200031 China Fax 86 21 54921011 Tel 86 21 54921165 E-mail zwqi@ or chi@ Received 23 August 2009 revised 20 October 2009 accepted 4 November 2009 doi The Bowman-Birk protease inhibitors have recently attracted attention for their potential as cancer preventive and suppressing agents. They contain two canonical binding loops both consisting of nine highly conserved residues capable of inhibiting corresponding serine proteases. In this study we cloned the cDNA of the mung bean trypsin inhibitor one of the most studied Bowman-Birk protease inhibitors. A modified peptide Lys33GP with 33 residues derived from the long chain of the Lys active fragment of mung bean trypsin inhibitor was successfully expressed in Escherichia coli as a glutathione-S-transferase fusion protein. The recombinant product was obtained with a high yield and exhibited potent inhibitory activity. Meanwhile a shorter peptide composed of only 16 residues the Lys16 peptide corresponding to the active core of the fragment was synthesized. Both the recombinant and the synthesized peptides had the same inhibitory activity toward trypsin at a molar ratio of 1 1 implying that the Lys16 peptide with two disulfide bonds is possibly the essential structural unit for inhibitory activity. Using site-directed mutagenesis the P1 position Lys was replaced by Phe