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Publication Abstract from PubMed

The heterobimetallic R2lox protein binds both manganese and iron ions in a site-selective fashion and activates oxygen, ultimately performing C-H bond oxidation to generate a tyrosine-valine crosslink near the active site. In this work, we demonstrate that following assembly, R2lox undergoes photoinduced changes to the active site geometry and metal coordination motif. Through spectroscopic, structural, and mass spectrometric characterization, the photoconverted species is found to consist of a tyrosinate-bound iron center following light-induced decarboxylation of a coordinating glutamate residue and cleavage of the tyrosine-valine crosslink. This process occurs with high quantum efficiencies (phi= 3%) using violet and near-ultraviolet light, suggesting that the photodecarboxylation is initiated via ligand-to-metal charge transfer excitation. Site-directed mutagenesis and structural analysis suggest that the crosslinked tyrosine-162 is the coordinating residue. One primary product is observed following irradiation, indicating potential use of this class of proteins, which contains a putative substrate channel, for controlled photoinduced decarboxylation processes, with relevance for in vivo functionality of R2lox as well as application in environmental remediation.

Driving protein conformational changes with light: Photoinduced structural rearrangement in a heterobimetallic oxidase.,Maugeri PT, Griese JJ, Branca RM, Miller EK, Smith ZR, Eirich J, Hogbom M, Shafaat HS J Am Chem Soc. 2017 Dec 22. doi: 10.1021/jacs.7b11966. PMID:29268610^[1]

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