tailieunhanh - Báo cáo khoa học: Hepatocyte growth factor activator (HGFA): molecular structure and interactions with HGFA inhibitor-1 (HAI-1)

The trypsin-like serine protease hepatocyte growth factor activator (HGFA) undergoes proteolytic activation during blood coagulation, result-ing in a 34 kDa ‘short form’, consisting mainly of the protease domain. The crystal structures of the recombinantly expressed HGFA ‘short form’ discussed herein have provided molecular insights into its interaction with inhibitors and substrates, as well as the regulation of catalytic activity. | ỊFEBS Journal MINIREVIEW Hepatocyte growth factor activator HGFA molecular structure and interactions with HGFA inhibitor-1 HAI-1 Charles Eigenbrot1 2 Rajkumar Ganesan3 and Daniel Kirchhofer3 1 Department of StructuralBiology Genentech Inc. South San Francisco CA USA 2 Department of Antibody Engineering Genentech Inc. South San Francisco CA USA 3 Department of Protein Engineering Genentech Inc. South San Francisco CA USA Keywords catalysis hepatocyte growth factor Kunitz domain serine protease structure Correspondence D. Kirchhofer Genentech Inc. 1 DNA Way South San Francisco CA 94080 USA Fax 1 650 225-3734 Tel 1 650 225-2134 E-mail dak@ Received 13 November 2009 revised 19 January 2010 accepted 8 February 2010 doi The trypsin-like serine protease hepatocyte growth factor activator HGFA undergoes proteolytic activation during blood coagulation resulting in a 34 kDa short form consisting mainly of the protease domain. The crystal structures of the recombinantly expressed HGFA short form discussed herein have provided molecular insights into its interaction with inhibitors and substrates as well as the regulation of catalytic activity. The HGFA structures revealed enzymatically competent and noncompetent forms associated with the conformational states of two substrate specificity-determining loops the 220-loop and 99-loop. The implied dynamic behavior of these loops which are intimately involved in substrate interaction has precedents in other members of the S1 family of serine proteases and may be associated with specific mechanisms of enzyme regulation. Furthermore HGFA activity is strongly inhibited by HGFA inhibitor-1 a membrane-spanning multidomain inhibitor containing two Kunitz domains of which only the N-terminal Kunitz domain-1 KD1 inhibits enzymatic activity. In the structure of the KD1-HGFA complex the inhibitor interacts with the active site region by making contacts with all substrate specificity-determining loops