Biochemical basis of resistance to hygromycin B in Streptomyces hygroscopicus - the producing organism

Abstract

Hygromycin B, an aminocyclitol antibiotic that strongly inhibits both 70sand 80s ribosomes, is synthesized by Streptomyces hygroscopicus. Ribosomes from this Gram-positive mycelial bacterium are inhibited in vitro by the antibiotic. In contrast, the streptomycete is highly resistant to the drug in vivo since it possesses hygromycin B phosphotransferase activity. This enzyme has been shown by gel filtration to have a molecular weight of 42000,and to modify its antibiotic substrate to produce 7>-O-phosphoryl-hygromycinB which totally lacks biological activity both in vivo and in vitro.