cDNAs ENCODING MINOR AMPULLATE SPIDER SILK PROTEINS

摘要

cDNA clones encoding minor ampullate spidroin proteins (MiSP) are described. The translated amino acid sequence of the cloned cDNA shows that the MiSPs have a structure which exhibits an amino proximal nonrepetitive region, a repetitive portion and a carboxy-proximal nonrepetitive portion. The repetitive portion of the sequence is describable by a generic repeat formula. Comparison of the amino acid sequences derived from the translation with the sequences of short peptides obtained from solubilized minor ampullate spider silk suggests that the nonrepetitive portions of the protein are cleaved from the protein during secretion from the cells synthesizing the spidroins. This comparison also suggests that the minor ampullate spider silk is composed of at least three polypeptides.