earticle

영어

Gentamicin belongs to the group of 4,6-disubstituted aminoglycosides containing a characteristic core aminocyclitol moiety, 2-deoxystreptamine (2-DOS). Various sets of candidate genes from M. echinospora and other related aminoglycoside-producing strains were introduced into a non-aminoglycoside producing strain of Streptomyces venezuelae. Heterologous expression of different combinations of putative 2-DOS biosynthetic genes revealed that a subset, gtmB-gtmA-gacH, is responsible for the biosynthesis of this core aminocyclitol moiety of gentamicin. Expression of gtmG together with gtmB-gtmA-gacH led to production of 2’-N-acetylparomamine demonstrating that GtmG acts as a glycosyltransferase that adds N-acetyl-D-glucosamine (GLcNA) to 2-DOS. Expression of btrD from Bacillus circulans or a homologue thereof (kacA from S. kanamyceticus or neo16 from S. fradiae) in a 2’-N-acetylparomamine-producing recombinant S. venezuelae strain generated paromamine. Expression of gtmE in an engineered paromamine-producing strain of S. venezuelae successfully generated gentamicin A2. These results represent the first in vivo evidence elucidating the complete biosynthetic pathway of the pseudotrisaccharide aminoglycoside.