sr-Thermus Thermophilus Polypeptide-1 is a single chain recombinant protein produced by fermentation in yeast. The starting gene is synthesized to be identical to the gene which codes for Deoxyribodipyrimidine Photo-lyase derived from Thermus thermophilus. The protein contains 420 amino acids which may contain disulfide bonds and/or glycosylation, and consists of the proper sequence of the 20 standard amino acids.