tailieunhanh - Báo cáo khoa học: The potent inhibitory activity of histone H1.2 C-terminal fragments on furin

Many physiologically important proproteins, pathogenic bacterial exo-toxins and viral envelope glycoproteins are activated by the proprotein con-vertase furin, which makes furin inhibitor a hot target for basic research and drug design. Although synthetic and bioengineered inhibitors of furin have been well characterized, its endogenous inhibitor has not been directly purified from mammalian tissues to date. | ỊFEBS Journal The potent inhibitory activity of histone C-terminal fragments on furin Jinbo Han1 Ling Zhang2 Xiaoxia Shao2 Jiahao Shi1 and Chengwu Chi1 2 1 Institute of Biochemistry and CellBiology Chinese Academy of Sciences Graduate Schoolof the Chinese Academy of Sciences Shanghai China 2 Institute of Protein Research Tong-ji University Shanghai China Keywords furin gene expression histone H1 inhibitory activity limited proteolysis peptide synthesis Correspondence C. Chi Shanghai Institute of Biochemistry and Cell Biology Chinese Academy of Sciences 320 Yue Yang Road Shanghai 200031 China Fax 86 21 54921011 Tel 86 21 54921165 E-mail chi@. Received 28 April2006 revised 27 July 2006 accepted 4 August 2006 doi Many physiologically important proproteins pathogenic bacterial exotoxins and viral envelope glycoproteins are activated by the proprotein con-vertase furin which makes furin inhibitor a hot target for basic research and drug design. Although synthetic and bioengineered inhibitors of furin have been well characterized its endogenous inhibitor has not been directly purified from mammalian tissues to date. In this study three inhibitors were purified from the porcine liver by using a combination of chromatographic techniques and identified to be the C-terminal truncated fragments with different sizes of histone . The gene of porcine histone was cloned and sequenced further confirming the determined sequences. These three C-terminal fragments inhibited furin with Ki values around 2 X 10 7 M while the full-length histone inhibited it with a lesser activity suggesting that the inhibitory activity relies on the C-terminal lysine-rich domain. Though the inhibition was temporary these inhibitors were specific and the reactive site of one C-terminal fragment was identified. A 36 amino acid peptide around the reactive site was synthesized which could still inhibit furin with a Ki of X 10 7 M. .