9r5l

Crystal structure of class Ie ribonucleotide reductase R2 subunit from Mesoplasma florum with a D212N mutation

spinqualitylabelsall models 9r5l, resolution 1.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 9r5l is a 1 chain structure with sequence from Mesoplasma florum L1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.7Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q6F0T5_MESFL Publication Abstract from PubMed Ribonucleotide reductases (RNRs) catalyze the conversion of ribonucleotide (RNA) to deoxyribonucleotide (DNA) building blocks initiated by a long-range (>30 A) proton-coupled electron transfer (PCET) by mechanistic principles that remain much debated. By combining multiscale quantum and classical simulations with directed mutagenesis, X-ray crystallography, and vibrational and electron paramagnetic resonance spectroscopy, we elucidate here the molecular principles underlying how metal-free RNRs initiate the long-range PCET process by creating a highly stable 3,4-dihydroxyphenylalanine (DOPA) initiator radical. We show that DOPA* is redox-tuned by a low-barrier hydrogen bond (LBHB), with a delocalized proton that provides the catalytic power for the ribonucleotide reduction. We find that the LBHB couples to an extended hydrogen-bonded network, with distant mutations resulting in the loss of radical formation, and providing key molecular insight into the long-range radical transport mechanism in RNRs. On a general level, our findings support the direct involvement of LBHB in protein chemistry and the importance of quantum effects in enzyme catalysis. Low-barrier hydrogen bond powers long-range radical transfer in the metal-free ribonucleotide reductase.,Sirohiwal A, John J, Kutin Y, Kumar R, Baserga F, Srinivas V, Lebrette H, Poverlein MC, Gamiz-Hernandez AP, Heberle J, Kasanmascheff M, Hogbom M, Kaila VRI Proc Natl Acad Sci U S A. 2026 May 12;123(19):e2529856123. doi: , 10.1073/pnas.2529856123. Epub 2026 May 7. PMID:42096306 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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