4m7s
Crystal structure of SeMet BtrN in an OPEN conformation
Structural highlights
FunctionBTRN_NIACI Catalyzes the radical S-adenosyl-L-methionine (SAM)-dependent two-electron oxidation of 2-deoxy-scyllo-inosamine (DOIA) to amino-dideoxy-scyllo-inosose (amino-DOI) in the biosynthetic pathway of butirosin.[1] Publication Abstract from PubMedThe 2-deoxy-scyllo-inosamine (DOIA) dehydrogenases are key enzymes in the biosynthesis of 2-deoxystreptamine-containing aminoglycoside antibiotics. In contrast to most DOIA dehydrogenases, which are NAD-dependent, the DOIA dehydrogenase from Bacillus circulans (BtrN) is an S-adenosyl-l-methionine (AdoMet) radical enzyme. To examine how BtrN employs AdoMet radical chemistry, we have determined its structure with AdoMet and substrate to 1.56 A resolution. We find a previously undescribed modification to the core AdoMet radical fold: instead of the canonical (beta/alpha)6 architecture, BtrN displays a (beta5/alpha4) motif. We further find that an auxiliary [4Fe-4S] cluster in BtrN, thought to bind substrate, is instead implicated in substrate-radical oxidation. High structural homology in the auxiliary cluster binding region between BtrN, fellow AdoMet radical dehydrogenase anSME, and molybdenum cofactor biosynthetic enzyme MoaA provides support for the establishment of an AdoMet radical structural motif that is likely common to approximately 6,400 uncharacterized AdoMet radical enzymes. X-ray analysis of butirosin biosynthetic enzyme BtrN redefines structural motifs for AdoMet radical chemistry.,Goldman PJ, Grove TL, Booker SJ, Drennan CL Proc Natl Acad Sci U S A. 2013 Sep 18. PMID:24048029[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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