title: Comparative proteome analysis of multi-layer cocoon of the silkworm, Bombyx mori.
abstract: Bombyx mori cocoon has a multi-layer structure that provides optimal protection for silkworm pupa. Research on the mechanical properties of the multi-layer structure revealed structure-property relationships of the cocoon. Here, we investigated the protein components of the B. mori cocoon in terms of its multi-layer structure. Liquid chromatography-tandem mass spectrometry identified 286 proteins from the multiple cocoon layers. In addition to fibroins and sericins, we identified abundant protease inhibitors, seroins and proteins of unknown function. By comparing protein abundance across layers, we found that the outermost layer contained more sericin1 and protease inhibitors and the innermost layer had more seroin1. As many as 36 protease inhibitors were identified in cocoons, showing efficient inhibitory activities against a fungal protease. Thus, we propose that more abundant protease inhibitors in the outer cocoon layers may provide better protection for the cocoon. This study increases our understanding of the multi-layer mechanism of cocoons, and helps clarify the biological characteristics of cocoons. The data have been deposited to the ProteomeXchange with identifier PXD001469.
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China.
authors: Yan
authors: Y
authors: Zhang
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China.
authors: Ping
authors: P
authors: Zhao
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China.
authors: Zhaoming
authors: Z
authors: Dong
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China.
authors: Dandan
authors: D
authors: Wang
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China.
authors: Pengchao
authors: P
authors: Guo
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China.
authors: Xiaomeng
authors: X
authors: Guo
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China.
authors: Qianru
authors: Q
authors: Song
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China.
authors: Weiwei
authors: W
authors: Zhang
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China.
authors: Qingyou
authors: Q
authors: Xia
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D012831:Bombyx / Q000378:metabolism*; D008969:Molecular Sequence Data; D010447:Peptide Hydrolases / Q000378:metabolism; D011480:Protease Inhibitors / Q000737:chemistry / Q000378:metabolism; D059748:Proteolysis; D020543:Proteome / Q000378:metabolism*; D040901:Proteomics; D016415:Sequence Alignment
chemical_list: D011480:Protease Inhibitors; D020543:Proteome; D010447:Peptide Hydrolases