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Publication Abstract from PubMed

MycG is a P450 monooxygenase that catalyzes the sequential hydroxylation and epoxidation of mycinamicin IV (M-IV), the last two steps in the biosynthesis of mycinamicin II, a macrolide antibiotic isolated from Micromonospora griseorubida. The crystal structure of MycG with M-IV bound was previously determined but showed the bound substrate in an orientation that did not rationalize the observed regiochemistry of M-IV hydroxylation. Nuclear magnetic resonance paramagnetic relaxation enhancements provided evidence of an orientation of M-IV in the MycG active site more compatible with the observed chemistry, but substrate-induced changes in the enzyme structure were not characterized. We now describe the use of amide 1H-15N residual dipolar couplings as experimental restraints in solvated "soft annealing" molecular dynamics simulations to generate solution structural ensembles of M-IV-bound MycG. Chemical shift perturbations, hydrogen-deuterium exchange, and 15N relaxation behavior provide insight into the dynamic and electronic perturbations in the MycG structure in response to M-IV binding. The solution and crystallographic structures are compared, and the possibility that the crystallographic orientation of bound M-IV represents an inhibitory mode is discussed.

Solution Conformations and Dynamics of Substrate-Bound Cytochrome P450 MycG.,Tietz DR, Podust LM, Sherman DH, Pochapsky TC Biochemistry. 2017 May 30;56(21):2701-2714. doi: 10.1021/acs.biochem.7b00291., Epub 2017 May 16. PMID:28488849^[4]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.