Related Experiment Video
Updated: Aug 21, 2026

Monitoring the Reductive and Oxidative Half-Reactions of a Flavin-Dependent Monooxygenase using Stopped-Flow Spectrophotometry
Published on: March 18, 2012
Cofactor-apoprotein hydrogen bonding in oxidized and fully reduced flavodoxin monitored by trans-hydrogen-bond scalar
Frank Löhr1, Gary N Yalloway, Stephen G Mayhew
1Institut für Biophysikalische Chemie, Zentrum für Biomolekulare Magnetische Resonanz, Johann Wolfgang Goethe-Universität, Marie Curie-Strasse 9, 60439 Frankfurt am Main, Germany.
Abstract:
Hydrogen bonding plays a key role in the tight binding of the FMN cofactor and the regulation of its redox properties in flavodoxins. Hydrogen bonding interactions can be directly observed in solution by multidimensional heteronuclear NMR spectroscopy through the scalar couplings between donor and acceptor nuclei. Here we report on the detection of intermolecular trans-hydrogen-bond couplings ((h)J) between the flavin ring system and the backbone of Desulfovibrio vulgaris flavodoxin in the oxidized and the two-electron reduced states. For this purpose, experiments are adapted from pulse sequences previously applied to determining (h)J coupling constants in nucleic acid-base pairs and proteins. The resulting (h2)J(N,N), (h4)J(N,N), (h3)J(C,N), and (h1)J(H,N) couplings involve the (15)N(1), (13)C(2), and (15)N(3) nuclei of the pyrimidine moiety of FMN, whereas no such interactions are detectable for (13)C(4) and (15)N(5). Several long-range (15)N-(15)N, (13)C-(15)N, and (1)H-(15)N J-coupling constants within the flavin are obtained as "by-products". The magnitudes of both (h)J and regular J couplings are found to be dependent on the redox state. In general, good correlations between (h)J coupling constants and donor-group (1)H chemical shifts and also crystallographic donor-acceptor distances are observed.
More Related Videos
10:01Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase
Published on: December 4, 2017
10:24Defining Hsp33's Redox-regulated Chaperone Activity and Mapping Conformational Changes on Hsp33 Using Hydrogen-deuterium Exchange Mass Spectrometry
Published on: June 7, 2018
Related Concept Videos
Cofactors and Coenzymes
Cofactors can be metallic ions or organic molecules called coenzymes. These types of helper...
Cofactors and Coenzymes
Cofactors and Coenzymes
Role of Reduced Coenzymes NADH and FADH₂
Oxidation of Phenols to Quinones
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox property is crucial in...
Electron Transport Chain: Complex III and IV