Variations in protein-flavin hydrogen bonding in a light, oxygen, voltage domain produce non-Arrhenius kinetics of adduct decay

Brian D. Zoltowski, Abigail I. Nash, Kevin H. Gardner

Research output: Contribution to journalArticle

25 Scopus citations

Abstract

Light, oxygen, voltage (LOV) domains utilize a conserved blue light-dependent mechanism to control a diverse array of effector domains in biological and engineered proteins. Variations in the kinetics and efficiency of LOV photochemistry fine-tune various aspects of the photic response. Characterization of the kinetics of a key aspect of this photochemical mechanism in EL222, a blue light responsive DNA binding protein from Erythrobacter litoralis HTCC2594, reveals unique non-Arrhenius behavior in the rate of dark-state cleavage of the photochemically generated adduct. Sequence analysis and mutagenesis studies establish that this effect stems from a Gln to Ala mutation unique to EL222 and homologous proteins from marine bacteria. Kinetic and spectroscopic analyses reveal that hydrogen bonding interactions between the FMN N1, O2, and ribityl hydroxyls and the surrounding protein regulate photocycle kinetics and stabilize the LOV active site from temperature-induced alteration in local structure. Substitution of residues interacting with the N1-O2 locus modulates adduct stability, structural flexibility, and sequestration of the active site from bulk solvent without perturbation of light-activated DNA binding. Together, these variants link non-Arrhenius behavior to specific alteration of an H-bonding network, while affording tunability of photocycle kinetics.

Original languageEnglish (US)
Pages (from-to)8771-8779
Number of pages9
JournalBiochemistry
Volume50
Issue number41
DOIs
StatePublished - Oct 18 2011

ASJC Scopus subject areas

  • Biochemistry

Fingerprint Dive into the research topics of 'Variations in protein-flavin hydrogen bonding in a light, oxygen, voltage domain produce non-Arrhenius kinetics of adduct decay'. Together they form a unique fingerprint.

  • Cite this