sr-Spider Polypeptide-2 is a single chain recombinant spider protein, produced by fermentation in E. coli. The starting gene is a synthetically derived copy of the gene from Araneus diadematus which codes for Fibroin-3. The protein contains a maximum of 636 amino acids which may contain disulfide bonds and/or glycosylation, and consists of the proper sequence of the 20 standard amino acids.