Analysis of a new type of major ampullate spider silk gene, MaSp1s.

Spider dragline silk, which is secreted from the major ampullate silk glands, is a unique fibrous protein with a combination of tensile strength and elasticity. Here, we describe a new short type of dragline silk gene, Cyrtophora moluccensis MaSp1s. The full-length gene is only 1320 base pairs (bp), which encodes 439 amino acids that includes the intact non-repetitive N-terminal (149 residues), C-terminal (98 residues) and so-called repetitive regions (192 residues); the deduced molecular weight is approximately 40 kDa. The sequence analysis demonstrated that the two termini are highly homologous to the other characterized dragline silk genes but that the so-called repetitive region is different. Our results suggest that MaSp1s is a possible new characteristic dragline gene; the discovery of this gene should enhance our understanding of the major ampullate spider silk genes.