Isolation and Purification of Two Novel Streptomycete RNase Inhibitors, SaI14 and SaI20, and Cloning, Sequencing, and Expression in<i>Escherichia coli</i>of the Gene Coding for SaI14

Abstract

ABSTRACTTwo new RNase inhibitors, SaI14 (Mr, ∼14,000) and SaI20 (Mr, ∼20,000), were isolated and purified from aStreptomyces aureofaciensstrain. The genesai14, coding for SaI14 protein, was cloned and expressed inEscherichia coli. The alignment of the deduced amino acid sequence of SaI14 with that of barstar, the RNase inhibitor fromBacillus amyloliquefaciens, showed significant similarity between them, especially in the region which contains most of the residues involved in barnase-barstar complex formation.</jats:p