title: Substrate binding modulates the reduction potential of DNA photolyase.
abstract: The reduction potential of the (FADH-/FADH*) couple in DNA photolyase was measured, and the value was found to be significantly higher than the values estimated in the literature. In the absence of substrate, the enzyme has a reduction potential of 16 +/- 6 mV vs NHE. In the presence of excess substrate the reduction potential increases to 81 +/- 8 mV vs NHE. The increase in reduction potential has physiological relevance since it gives the catalytic state greater resistance to oxidation. This is the first measurement of a reduction potential for this class of DNA-repair enzymes and the larger family of blue-light photoreceptors.
authors.affiliation: Department of Chemistry, Lafayette College, Easton, Pennsylvania 18042, USA. gindty@lafayette.edu
authors.forename: Yvonne M
authors.initials: YM
authors.lastname: Gindt
authors.forename: Johannes P M
authors.initials: JP
authors.lastname: Schelvis
authors.forename: Katie L
authors.initials: KL
authors.lastname: Thoren
authors.forename: Tina H
authors.initials: TH
authors.lastname: Huang
mesh_terms: D002384:Catalysis; D004260:DNA Repair; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000737:chemistry / Q000378:metabolism*; D004563:Electrochemistry; D004795:Enzyme Stability; D005182:Flavin-Adenine Dinucleotide / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D010084:Oxidation-Reduction; D011740:Pyrimidine Dimers / Q000378:metabolism
chemical_list: D011740:Pyrimidine Dimers; D005182:Flavin-Adenine Dinucleotide; C029276:flavin semiquinone; D004255:Deoxyribodipyrimidine Photo-Lyase