title: Silk gland-specific proteinase inhibitor serpin16 from the Bombyx mori shows cysteine proteinase inhibitory activity.
abstract: Serpins (serine proteinase inhibitors) are widely distributed in different species and are well known for their inhibitory activities towards serine proteinases. Here, we report the functional characterization of Bombyx mori serpin16. Expression analysis showed that serpin16 was specifically expressed at high levels in the silk gland at both the transcriptional and translational levels. Moreover, homology modeling and multi-sequence alignment suggested that serpin16 had a canonical serpin fold, but it contained a unique reactive center loop, which was obviously shorter than that of typical serpins. Inhibitory activity analyses revealed that the target proteinase of serpin18 is a cysteine proteinase, rather than a serine proteinase. Furthermore, a Michaelis complex model of serpin16 with its target proteinase was constructed to explain the structural basis of how serpin16 recognizes the cysteine proteinase and its target specificity.
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, 216, Tiansheng Road, Beibei, Chongqing 400716, People's Republic of China.
authors.forename: Peng-Chao
authors.initials: PC
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, 216, Tiansheng Road, Beibei, Chongqing 400716, People's Republic of China.
authors.forename: Zhaoming
authors.initials: Z
authors.lastname: Dong
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, 216, Tiansheng Road, Beibei, Chongqing 400716, People's Republic of China.
authors.forename: Li
authors.initials: L
authors.lastname: Xiao
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, 216, Tiansheng Road, Beibei, Chongqing 400716, People's Republic of China.
authors.forename: Tao
authors.initials: T
authors.lastname: Li
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, 216, Tiansheng Road, Beibei, Chongqing 400716, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, 216, Tiansheng Road, Beibei, Chongqing 400716, People's Republic of China.
authors.forename: Huawei
authors.initials: H
authors.lastname: He
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, 216, Tiansheng Road, Beibei, Chongqing 400716, People's Republic of China.
authors.forename: Qingyou
authors.initials: Q
authors.lastname: Xia
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, 216, Tiansheng Road, Beibei, Chongqing 400716, People's Republic of China. Electronic address: zhaop@swu.edu.cn.
authors.forename: Ping
authors.initials: P
authors.lastname: Zhao
mesh_terms: D000595:Amino Acid Sequence; D000825:Animal Structures / Q000378:metabolism*; D000818:Animals; D012831:Bombyx / Q000378:metabolism*; D057056:Cysteine Proteases / Q000378:metabolism*; D005786:Gene Expression Regulation; D019476:Insect Proteins / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009928:Organ Specificity; D011480:Protease Inhibitors / Q000737:chemistry / Q000378:metabolism*; D020539:Sequence Analysis, Protein; D047011:Silk / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D019476:Insect Proteins; D011480:Protease Inhibitors; D047011:Silk; D057056:Cysteine Proteases
keywords: Bombyx mori; Inhibitory activity; Serpin (serine proteinase inhibitor); Silk gland-specific; Structure