Biosynthesis of the carbamoylated D-gulosamine moiety of streptothricins: involvement of a guanidino-N-glycosyltransferase and an N-acetyl-D-gulosamine deacetylase.
Streptothricins (STNs) are atypical aminoglycosides containing a rare carbamoylated D-gulosamine (D-GulN) moiety, and the antimicrobial activity of STNs has been exploited for crop protection. Herein, the biosynthetic pathway of the carbamoylated D-GulN moiety was delineated. An N-acetyl-D-galactosamine is first attached to the streptolidine lactam by the glycosyltransferse StnG and then epimerized to N-acetyl-D-gulosamine by the putative epimerase StnJ. After carbamoylation by the carbamoyltransferase StnQ, N-acetyl-D-GulN is deacetylated by StnI to furnish the carbamoylated D-GulN moiety. In vitro studies characterized two novel enzymes: StnG is an unprecedented GT-A fold N-glycosyltransferase that glycosylates the imine nitrogen atom of guanidine, and StnI is the first reported N-acetyl-D-GulN deacetylase.
State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101 (China).
Zhengyan
Z
Guo
Jine
J
Li
Hua
H
Qin
Min
M
Wang
Xun
X
Lv
Xuebing
X
Li
Yihua
Y
Chen
D000900:Anti-Bacterial Agents / Q000096:biosynthesis / Q000737:chemistry / Q000494:pharmacology; D019878:Carboxyl and Carbamoyl Transferases / Q000378:metabolism*; D006031:Glycosylation; D016695:Glycosyltransferases / Q000378:metabolism*; D005810:Multigene Family; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects; D013302:Streptomyces / Q000235:genetics; D013309:Streptothricins / Q000096:biosynthesis* / Q000737:chemistry / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D013309:Streptothricins; D019878:Carboxyl and Carbamoyl Transferases; D016695:Glycosyltransferases
D-gulosamine; aminoglycoside; biosynthesis; deacetylation; glycosylation