title: The molecular structures of major ampullate silk proteins of the wasp spider, Argiope bruennichi: a second blueprint for synthesizing de novo silk.
abstract: The dragline silk of orb-weaving spiders possesses extremely high tensile strength and elasticity. To date, full-length sequences of only two genes encoding major ampullate silk protein (MaSp) in Latrodectus hesperus have been determined. In order to further understand this gene family, we utilized in this study a variety of strategies to isolate full-length MaSp1 and MaSp2 cDNAs in the wasp spider Argiope bruennichi. A. bruennichi MaSp1 and MaSp2 are primarily composed of remarkably homogeneous ensemble repeats containing several complex motifs, and both have highly conserved C-termini and N-termini. Two novel amino acid motifs, GGF and SGR, were found in MaSp1 and MaSp2, respectively. Amino acid composition analysis of silk, luminal contents and predicted sequences indicates that MaSp1 and MaSp2 are two major components of major ampullate glands and that the ratio of MaSp1 to MaSp2 is approximately 3:2 in dragline silk. Furthermore, both the MaSp1:MaSp2 ratio and the conserved termini are closely linked with the production of high quality synthetic fibers. Our results make an important contribution to our understanding of major ampullate silk protein structure and provide a second blueprint for creating new composite silk which mimics natural spider dragline silk.
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, ChongQing 400715, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Ai-Chun
authors.initials: AC
authors.lastname: Zhao
authors.forename: Yang-Hu
authors.initials: YH
authors.lastname: Sima
authors.forename: Cheng
authors.initials: C
authors.lastname: Lu
authors.forename: Zhong-Huai
authors.initials: ZH
authors.lastname: Xiang
authors.forename: Masao
authors.initials: M
authors.lastname: Nakagaki
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000378:metabolism; D000825:Animal Structures / Q000378:metabolism*; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005349:Fibroins / Q000096:biosynthesis* / Q000737:chemistry* / Q000235:genetics; D057927:Hydrophobic and Hydrophilic Interactions; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013112:Spiders / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D018076:DNA, Complementary; D005349:Fibroins