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Publication Abstract from PubMed

The cytochrome P450 OleP catalyzes the epoxidation of aliphatic carbons on both the aglycone 8.8a-deoxyoleandolide (DEO) and the monoglycosylated L-olivosyl-8.8a-deoxyoleandolide (L-O-DEO) intermediates of oleandomycin biosynthesis. We investigated the substrate versatility of the enzyme. X-ray and equilibrium binding data show that the aglycone DEO loosely fits the OleP active site, triggering the closure that prepares it for catalysis only on a minor population of enzyme. The open-to-closed state transition allows solvent molecules to accumulate in a cavity that forms upon closure, mediating protein-substrate interactions. In silico docking of the monoglycosylated L-O-DEO in the closed OleP-DEO structure shows that the L-olivosyl moiety can be hosted in the same cavity, replacing solvent molecules and directly contacting structural elements involved in the transition. X-ray structures of aglycone-bound OleP in the presence of L-rhamnose confirm the cavity as a potential site for sugar binding. All considered, we propose L-O-DEO as the optimal substrate of OleP, the L-olivosyl moiety possibly representing the molecular wedge that triggers a more efficient structural response upon substrate binding, favoring and stabilizing the enzyme closure before catalysis. OleP substrate versatility is supported by structural solvent molecules that compensate for the absence of a glycosyl unit when the aglycone is bound.

Dissecting the Cytochrome P450 OleP Substrate Specificity: Evidence for a Preferential Substrate.,Parisi G, Freda I, Exertier C, Cecchetti C, Gugole E, Cerutti G, D'Auria L, Macone A, Vallone B, Savino C, Montemiglio LC Biomolecules. 2020 Oct 6;10(10). pii: biom10101411. doi: 10.3390/biom10101411. PMID:33036250^[1]

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