On the midpoint potential of the FAD chromophore in a BLUF-domain containing photoreceptor protein.
The redox-midpoint potential of the FAD chromophore in the BLUF domain of anti-transcriptional regulator AppA from Rhodobacter sphaeroides equals ∼-260mV relative to the calomel electrode. Altering the structure of its chromophore-binding pocket through site-directed mutagenesis brings this midpoint potential closer to that of free flavin in aqueous solution. The redox-midpoint potential of this BLUF domain is intermediate between those of LOV domains and Cryptochromes, which may rationalize the primary photochemistry observed in these three flavin-containing photoreceptor families. These results also imply that LOV domains, among the flavin-containing photosensory receptors, are least sensitive to intracellular chemical reduction in the dark.
Swammerdam Institute for Life Science, University of Amsterdam, Amsterdam, The Netherlands.
Jos C
JC
Arents
Marcela Avila
MA
Perez
Johnny
J
Hendriks
Klaas J
KJ
Hellingwerf
D000465:Algorithms; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites / Q000235:genetics; D056931:Cryptochromes / Q000737:chemistry / Q000378:metabolism; D005182:Flavin-Adenine Dinucleotide / Q000737:chemistry / Q000378:metabolism*; D005415:Flavins / Q000737:chemistry / Q000378:metabolism; D005420:Flavoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008027:Light; D016297:Mutagenesis, Site-Directed; D010084:Oxidation-Reduction / Q000187:drug effects / Q000528:radiation effects; D010100:Oxygen / Q000494:pharmacology; D020283:Photoreceptors, Microbial / Q000737:chemistry / Q000378:metabolism; D012242:Rhodobacter sphaeroides / Q000235:genetics / Q000378:metabolism*; D013053:Spectrophotometry
C116785:AppA protein, Rhodobacter sphaeroides; D001426:Bacterial Proteins; D056931:Cryptochromes; D005415:Flavins; D005420:Flavoproteins; D020283:Photoreceptors, Microbial; D005182:Flavin-Adenine Dinucleotide; D010100:Oxygen