Unique Molecular Architecture of Silk Fibroin in the Waxmoth,Galleria mellonella *
Unique Molecular Architecture of Silk Fibroin in the Waxmoth,Galleria mellonella *
复制标题
大蜡螟中丝素蛋白的独特分子结构 *
DOI：
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发表时间：
2002
影响因子：
4.8
通讯作者：
F. Sehnal
中科院分区：
文献类型：
--
作者：
M. Žurovec;F. Sehnal
Proteins of silk fibers are characterized by reiterations of amino acid repeats. Physical properties of the fiber are determined by the amino acid composition, the complexity of repetitive units, and arrangement of these units into higher order arrays. Except for very short motifs of 6–10 residues, the length of repetitive units and the number of these units concatenated in higher order assemblies vary in all spider and lepidopteran silks analyzed so far. This paper describes an exceptional silk protein represented by the 500-kDa heavy chain fibroin (H-fibroin) of the waxmoth,Galleria mellonella. Its non-repetitive N-terminal (175 residues) and C-terminal (60 residues) parts, the overall gene organization, and the nucleotide sequence around the TATA box show that it is homologous to the H-fibroins of other Lepidoptera. However, over 95% of the protein consists of highly ordered repetitive structures that are unmatched in other species. The repetitive region includes 11 assemblies AB1AB1AB1AB2(AB2)AB2of remarkably conserved polypeptide repeats A (63 amino acid residues), B1 (43 residues), and B2 (18 residues). The repeats contain a high proportion of Gly (31.6%), Ala (23.8%), Ser (18.1%), and of residues with long hydrophobic side chains (16% for Leu, Ile, and Val combined). The presence of the GLGGLG and SSAASAA(AA) motifs suggests formation of pleated β-sheets and their stacking into crystallites. Conspicuous conservation of the apolar sequence VIVI followed by DD or ED is interpreted as indicating the importance of hydrophobicity and electrostatic charge in H-fibroin cross-linking. The environment of G. mellonella larvae within bee cultures requires continuous production of silk that must be both strong and elastic. The spectacular arrangement of the repetitive H-fibroin region apparently evolved to meet these requirements.
影响因子：
3.8
作者：
CHERBAS, L;CHERBAS, P
通讯作者：
CHERBAS, P