Linear aglycones are the substrates for glycosyltransferase DesVII in methymycin biosynthesis: analysis and implications.
The two essential structural components of macrolide antibiotics are the polyketide aglycone and the appended sugars. The aglycone formation is catalyzed by polyketide synthase (PKS), and glycosylation is catalyzed by an appropriate glycosyltransferase. Although it has been shown that glycosylation occurs after the cyclic aglycone is released from PKS, it is not known whether the acyl carrier protein (ACP)-bound linear polyketide chain can also be processed by the corresponding glycosyltransferase. To explore this possibility, the aglycone, 10-deoxymethynolide, which is the precursor of methymycin and neomethymycin, was chemically synthesized in the linear form as a N-acetylcysteamine (NAC) thioester. Subsequent incubation with TDP-d-desosamine in the presence of the dedicated glycosyltransferase, DesVII, and activator, DesVIII, produces a more polar product whose high-resolution mass is consistent with the anticipated glycosylated product. This study demonstrated for the first time that a macrolide glycosyltransferase can also recognize and process the linear precursor of its macrolactone substrate with a reduced but measurable activity.
Kao
Chai-Lin
CL
Division of Medicinal Chemistry, College of Pharmacy, and Department of Chemistry and Biochemistry, University of Texas, Austin, Texas 78712, USA.
Borisova
Svetlana A
SA
Kim
Hak Joong
HJ
Liu
Hung-wen
HW
D006031:Glycosylation; D016695:Glycosyltransferases / Q000378:metabolism*; D018942:Macrolides / Q000737:chemistry / Q000378:metabolism*; D013379:Substrate Specificity
D018942:Macrolides; C008517:methymycin; D016695:Glycosyltransferases