Gene inactivation study of gntE reveals its role in the first step of pseudotrisaccharide modifications in gentamicin biosynthesis.
A gene inactivation study was performed on gntE, a member of the gentamicin biosynthetic gene cluster in Micromonospora echinospora. Computer-aided homology analysis predicts a methyltransferase-related cobalamin-binding domain and a radical S-adenosylmethionine domain in GntE. It is also found that there is no gntE homolog within other aminoglycoside biosynthetic gene clusters. Inactivation of gntE was achieved in both M. echinospora ATCC 15835 and a gentamicin high-producer GMC106. High-performance liquid chromatographic analysis, coupled with mass spectrometry, revealed that gntE mutants accumulated gentamicin A2 and its derivative with a methyl group installed on the glucoamine moiety. This result substantiated that GntE participates in the first step of pseudotrisaccharide modifications in gentamicin biosynthesis, though the catalytic nature of this unusual oxidoreductase/methyltransferase candidate is not resolved. The present gene inactivation study also demonstrates that targeted genetic engineering can be applied to produce specific gentamicin structures and potentially new gentamicin derivatives in M. echinospora.
Department of Biological Science, Division of Bioscience and Bioinformatics, Myongji University, Yongin 449-728, Republic of Korea.
Jin-Yong
JY
Kim
Joo-Won
JW
Suh
Suk-Ho
SH
Kang
Thi Huyen
TH
Phan
Si-Hyung
SH
Park
Hyung-Jin
HJ
Kwon
D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D020868:Gene Silencing; D005818:Genetic Engineering; D005839:Gentamicins / Q000096:biosynthesis*; D008847:Micromonospora / Q000235:genetics / Q000378:metabolism*; D014312:Trisaccharides / Q000378:metabolism*
D001426:Bacterial Proteins; D005839:Gentamicins; D014312:Trisaccharides; C030880:gentamicin A