Chain Conformational Study on Underwater Silk Proteins from Caddisfly,Stenopsyche marmorata -Implication of a Fiber-forming Mechanism
Larval silk/cement proteins from a caddisfly, Stenopsyche marmorata, were isolated as a protein mixture of Smsp-1, 2, 3 and 4.Smsp-1 is a giant phosphorylated protein, which occupies ca.45%-mass of the silk gland content, and composed of a long-range periodic amino acid sequences, involving 8 kinds of characteristic segments.The silk protein film was prepared and drawn in water up to 9-folds of the initial axis length, then the drawn film was subjected to polarized FT-IR and WAXD.The results implied that the Smsp-1 backbone adopts two different conformations, one of which was the β-tum-like conformers.The molecular mechanic studies were separately performed to evaluate the solid-state chain structures of the hydrophobic/Pro-rich segments 3 and 4, which are enriched in the primary sequence of Smsp-l, and the results were coincident with those from the vibration spectra and WAXD.The molecular dynamic (MD) studies were also carried out in order to estimate their preferred chain conformations in a solution state.The MD trajectory suggests that the segments 3 and 4 tend to adopt a turn-like conformation, which is a potential precursor of the β-turn-like conformers.In conclusion, the underwater silk proteins have a fiber-forming mechanism, which is substantially different from a silkworm, Bombyx mori.
Silk proteins Caddisfly Stenopsyche mamorata Molecular Dynamic Conformer Search Computation
Kousaku Ohkawa Masakazu Hachisu Takaomi Nomura Ryoichi Arai Kimio Hirabayashi Masuhiro Tsukada Koji Abe
Institute of High Polymer Research,Faculty of Textile Science and Technology,Shinshu University,Japa Research Institute of Genome-based Biofactory,National Institute of Advanced Industrial Science and Division of Applied Biology,Faculty of Textile Science and Technology,Shinshu University,Japan Division of Chemistry and Materials,Faculty of Textile Science and Technology,Shinshu University,Jap
国际会议
苏州
英文
3-8
2013-09-09（万方平台首次上网日期，不代表论文的发表时间）