X-ray analysis of butirosin biosynthetic enzyme BtrN redefines structural motifs for AdoMet radical chemistry
Author(s)Goldman, Peter J.; Grove, Tyler L.; Booker, Squire J.; Drennan, Catherine L.
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The 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 Å resolution. We find a previously undescribed modification to the core AdoMet radical fold: instead of the canonical (β/α)[subscript 6] architecture, BtrN displays a (β[subscript 5]/α[subscript 4]) 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 ∼6,400 uncharacterized AdoMet radical enzymes.
DepartmentMassachusetts Institute of Technology. Department of Biology; Massachusetts Institute of Technology. Department of Chemistry
Proceedings of the National Academy of Sciences
National Academy of Sciences (U.S.)
Goldman, P. J., T. L. Grove, S. J. Booker, and C. L. Drennan. “X-Ray Analysis of Butirosin Biosynthetic Enzyme BtrN Redefines Structural Motifs for AdoMet Radical Chemistry.” Proceedings of the National Academy of Sciences 110, no. 40 (September 18, 2013): 15949–15954.
Final published version