title: Investigating the intermediates in the reaction of ribonucleoside triphosphate reductase from Lactobacillus leichmannii: An application of HF EPR-RFQ technology.
abstract: In this investigation high-frequency electron paramagnetic resonance spectroscopy (HFEPR) in conjunction with innovative rapid freeze-quench (RFQ) technology is employed to study the exchange-coupled thiyl radical-cob(II)alamin system in ribonucleotide reductase from a prokaryote Lactobacillus leichmannii. The size of the exchange coupling (Jex) and the values of the thiyl radical g tensor are refined, while confirming the previously determined (Gerfen et al. (1996) [20]) distance between the paramagnets. Conclusions relevant to ribonucleotide reductase catalysis and the architecture of the active site are presented. A key part of this work has been the development of a unique RFQ apparatus for the preparation of millisecond quench time RFQ samples which can be packed into small (0.5 mm ID) sample tubes used for CW and pulsed HFEPR--lack of this ability has heretofore precluded such studies. The technology is compatible with a broad range of spectroscopic techniques and can be readily adopted by other laboratories.
authors.affiliation: Department of Physiology and Biophysics, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY 10461, United States.
authors.forename: Julia
authors.initials: J
authors.lastname: Manzerova
authors.forename: Vladimir
authors.initials: V
authors.lastname: Krymov
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Gerfen
mesh_terms: D000465:Algorithms; D000693:Anaerobiosis; D016880:Anisotropy; D020134:Catalytic Domain; D004574:Electromagnetic Fields; D004578:Electron Spin Resonance Spectroscopy / Q000295:instrumentation / Q000379:methods*; D005615:Freezing; D005798:Genes, Bacterial; D007202:Indicators and Reagents; D052199:Lactobacillus leichmannii / Q000201:enzymology* / Q000235:genetics; D010957:Plasmids / Q000737:chemistry / Q000235:genetics; D011208:Powders; D012264:Ribonucleotide Reductases / Q000737:chemistry*; D013696:Temperature; D014805:Vitamin B 12 / Q000737:chemistry
chemical_list: D007202:Indicators and Reagents; D011208:Powders; D012264:Ribonucleotide Reductases; C057295:ribonucleoside-triphosphate reductase; D014805:Vitamin B 12