Cloning and expression of the streptavidin gene from Streptomyces avidiniiin Escherichia coli and secretion of streptavidin by E-coli cells

The streptavidin gene from Streptomyces avidinii was cloned, an expression plasmid constructed, and a highly effective strain producer of streptavidin created. It was shown that the leader peptide of streptavidin ensures the effective secretion of this protein into the periplasmic space of Escherich ia coli cells. The degradation site of the leader peptide was detected. Upo n treatment with the total fraction of proteases secreted by S. avidinii in to the culture medium. "core" streptavidin was obtained, which retained the biotin-binding function.