Structural highlights
Function[KANJ_STRKN] Mediates the conversion of kanamycin B into 2'-dehydrokanamycin A during the transformation of kanamycin B to kanamycin A.[1] Publication Abstract from PubMedKanamycin A is the major 2-deoxystreptamine (2DOS)-containing aminoglycoside antibiotic produced by Streptomyces kanamyceticus. The 2DOS moiety is linked with 6-amino-6-deoxy-d-glucose (6ADG) at O-4 and 3-amino-3-deoxy-d-glucose at O-6. Because the 6ADG moiety is derived from d-glucosamine (GlcN), deamination at C-2 and introduction of C-6-NH2 are required in the biosynthesis. A dehydrogenase KanQ and an aminotransferase KanB are presumed to be responsible for the introduction of C-6-NH2, although the substrates have not been identified. Here, we examined the substrate specificity of KanQ to better understand the biosynthetic pathway. It was found that KanQ oxidized kanamycin C more efficiently than the 3-deamino derivative. Furthermore, substrate specificity of an oxygenase KanJ, which is responsible for deamination at C-2 of the GlcN moiety, was examined, and the crystal structure of KanJ was determined. It was found that C-6-NH2 is important for substrate recognition by KanJ. Thus, the modification of the GlcN moiety occurs after pseudotrisaccharide formation, followed by the introduction of C-6-NH2 by KanQ/KanB and deamination at C-2 by KanJ. Stepwise Post-glycosylation Modification of Sugar Moieties in Kanamycin Biosynthesis.,Eguchi T, Kudo F, Kitayama Y, Miyanaga A, Numakura M Chembiochem. 2021 Jan 5. doi: 10.1002/cbic.202000839. PMID:33403742[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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