Detection of Water Molecules on the Radical Transfer Pathway of Ribonucleotide Reductase by 17 O Electron-Nuclear Double Resonance Spectroscopy.

Autor: Hecker F; Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany., Stubbe J; Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 20139, United States., Bennati M; Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.; Department of Chemistry, Georg-August-University, 37077 Göttingen, Germany.
Jazyk: angličtina
Zdroj: Journal of the American Chemical Society [J Am Chem Soc] 2021 May 19; Vol. 143 (19), pp. 7237-7241. Date of Electronic Publication: 2021 May 06.
DOI: 10.1021/jacs.1c01359
Abstrakt: The role of water in biological proton-coupled electron transfer (PCET) is emerging as a key for understanding mechanistic details at atomic resolution. Here we demonstrate 17 O high-frequency electron-nuclear double resonance (ENDOR) in conjunction with H 2 17 O-labeled protein buffer to establish the presence of ordered water molecules at three radical intermediates in an active enzyme complex, the α 2 β 2 E. coli ribonucleotide reductase. Our data give unambiguous evidence that all three, individually trapped, intermediates are hyperfine coupled to one water molecule with Tyr-O··· 17 O distances in the range 2.8-3.1 Å. The availability of this structural information will allow for quantitative models of PCET in this prototype enzyme. The results also provide a spectroscopic signature for water H-bonded to a tyrosyl radical.
Databáze: MEDLINE
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