title: A spider (Araneus ventricosus) chymotrypsin inhibitor that acts as an elastase inhibitor and a microbial serine protease inhibitor.
abstract: Spider-derived Kunitz-type serine protease inhibitors have been shown to exhibit plasmin and elastase inhibition activity and potassium channel blocking activity, but thus far, no additional roles for spider-derived chymotrypsin inhibitors have been elucidated. In this study, a spider (Araneus ventricosus) chymotrypsin inhibitor (AvCI) that acts as an elastase inhibitor and a microbial serine protease inhibitor was identified. AvCI is a 70-amino acid mature peptide that displays eight conserved cysteine residues and a P1 lysine residue. Recombinant AvCI expressed in baculovirus-infected insect cells demonstrated inhibitory activity against chymotrypsin (Ki 49.85 nM), but not trypsin, which defines a role for AvCI as a spider-derived chymotrypsin inhibitor. AvCI also exhibited inhibitory activity against microbial serine proteases such as subtilisin A (Ki 20.51 nM) and proteinase K (Ki 65.42 nM). Furthermore, AvCI exhibited no detectable inhibitory effects on factor Xa, thrombin, tissue plasminogen activator, or plasmin; however, AvCI strongly inhibited human neutrophil elastase (Ki 8.74 nM) and porcine pancreatic elastase (Ki 11.32 nM), indicating that AvCI acts as an anti-elastolytic factor. These findings constitute molecular evidence that AvCI acts as an inhibitor against chymotrypsin, microbial serine proteases, and elastases. This paper provides a novel view of the functions of a spider-derived chymotrypsin inhibitor.
authors.affiliation: Department of Plant Protection, Huazhong Agricultural University, Wuhan, PR China.
authors.forename: Hu
authors.initials: H
authors.lastname: Wan
authors.forename: Kwang Sik
authors.initials: KS
authors.lastname: Lee
authors.forename: Bo Yeon
authors.initials: BY
authors.lastname: Kim
authors.forename: Miao
authors.initials: M
authors.lastname: Yuan
authors.forename: Sha
authors.initials: S
authors.lastname: Zhan
authors.forename: Hong
authors.initials: H
authors.lastname: You
authors.forename: Jianhong
authors.initials: J
authors.lastname: Li
authors.forename: Byung Rae
authors.initials: BR
authors.lastname: Jin
mesh_terms: D000818:Animals; D002918:Chymotrypsin / Q000037:antagonists & inhibitors*; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology*; D013112:Spiders / Q000378:metabolism*
chemical_list: D015842:Serine Proteinase Inhibitors; D002918:Chymotrypsin; D010196:Pancreatic Elastase