Phototropin (phot) is a blue-light receptor in plants. The molecule has two FMN (flavin mononucleotide)-binding domains named the LOV (light−oxygen−voltage) domain, that subset of PAS (per−arnt−sim) superfamily. Illumination phot−LOV produces covalent C(4a) flavin−cysteinyl adduct, which called S390 intermediate state. According to crystal structures LOV2 domain Adiantum phytochrome3 (phy3), fusion protein phot containing phytochrome chromophoric unphotolyzed and states, side chain Gln1029...

Phototropin is a plant blue-light sensor protein that possesses flavin mononucleotide (FMN) as the chromophore in LOV domains. Its photoreaction an adduct formation between FMN and nearby cysteine takes place triplet excited state of FMN. In this communication, we revealed reactive protonated LOV2 domain Adiantum phytochrome3 by means low-temperature FTIR spectroscopy. hydrogen-bonding interaction strengthened state, presumably with chromophore. Such strong drives on microsecond time scale.

Phototropin is a blue-light receptor of plants and comprises two light-receptive domains, LOV1 LOV2, Ser/Thr kinase domain one linker region connecting the LOV2 domains. The thought to regulate predominantly light-dependent autophosphorylation domain, leading cellular signaling cascades. In this study, we constructed recombinant LOV1, LOV2-linker polypeptides from phototropin 1 2 Arabidopsis thaliana studied their quaternary structures conformational changes by small-angle X-ray scattering....

The polarization switching mechanism is used in various devices such as pyroelectric sensors and memory devices. change mostly occurs by ion displacement. development of materials whose switches via electron transfer order to enhance operation speed a challenge. We devised synthetic crystal engineering strategy that enables the selective synthesis [CrCo] heterometallic dinuclear complex with polar structure, wherein changes stem from intramolecular charge between Co ligand. Polarization can...

Phototropin (Phot) is a blue-light receptor in plants. The molecule has two FMN (flavin mononucleotide) binding domains named LOV (light-, oxygen-, and voltage-sensing), which subset of the PAS (Per-Arnt-Sim) superfamily. Illumination phot-LOV dark state (D447) produces covalent C(4a) flavin−cysteinyl adduct (S390) via triplet excited (L660), reverts to D447 dark. In this work, we studied light-induced structural changes LOV2 domain Adiantum phytochrome3 (phy3), fusion protein phot...

Three kinds of photochemical reactions are known in flavins as chromophores photosensor proteins, reflecting the various catalytic flavin flavoenzymes. Sensor blue light using FAD (BLUF) domains exhibit a unique photoreaction compared with other flavin-binding photoreceptors that chromophore does not change its chemical structure between unphotolyzed and intermediate states. Rather, hydrogen bonding environment is altered, whereby conserved Gln Tyr residues near play crucial role. One...

Phy3-LOV2 is the chromophore domain of a blue-light photoreceptor for tropic responses plants. FMN noncovalently bound to phy3-LOV2, and protein structure characteristic LOV (light-oxygen-voltage) domain. Primary photoreaction considered be adduct formation between cysteine, while deprotonation cysteine S-H group was suggested. On basis infrared spectral analysis, however, we have shown that phy3-LOV2 in protonated form, not thiolate form ground state. Upon S390, disappears, presumably...

Phototropin (phot) is a blue-light photoreceptor for phototropic responses, relocation of chloroplasts, and stomata opening in plants. has two chromophore-binding domains named LOV1 LOV2 its N-terminal half, each which binds flavin mononucleotide (FMN) noncovalently. The C-terminal half Ser/Thr kinase. A transgenic study Arabidopsis suggested that only domain necessary the kinase activity, whereas X-ray crystallographic structures are almost identical. These facts imply detailed and/or...

Phototropin, a blue-light photoreceptor in plants, has two FMN-binding domains named LOV1 and LOV2. We previously observed temperature-dependent FTIR spectral changes the C=O stretching region (amide-I vibrational of peptide backbone) for LOV2 domain Adiantum phytochrome3 (phy3-LOV2), suggesting progressive structural protein moiety (Iwata, T., Nozaki, D., Tokutomi, S., Kagawa, Wada, M., Kandori, H. (2003) Biochemistry 42, 8183-8191). Because FMN also possesses groups, this article, we aimed...

The bacterial reaction center (RC) is a membrane protein complex that performs photosynthetic electron transfer from bacteriochlorophyll dimer to quinone acceptors QA and QB. QB accepts electrons the primary quinone, QA, in two sequential reactions coupled uptake of proton solution. It has been suggested water molecules along pathway are protonated upon reduction on basis FTIR difference spectra [Breton, J., Nabedryk, E. (1998) Photosynth. Res. 55, 301−307]. We examined possible involvement...

Cryptochromes (Crys) and photolyases (Phrs) are flavoproteins that contain an identical cofactor (flavin adenine dinucleotide, FAD) within the same protein architecture but whose physiological functions entirely different. In this study, we investigated light-induced conformational changes of a cyanobacterium Cry/Phr-like (SCry-DASH) with UV-visible Fourier transform infrared (FTIR) spectroscopy. We developed system for measuring difference spectra under concentrated conditions. presence...

Flavin-binding Kelch repeat F-box (FKF1) protein plays important roles in the photoregulation of flowering Arabidopsis. FKF1 has a light, oxygen, and voltage (LOV) sensing domain binding flavin mononucleotide (FMN) as chromophore noncovalently. Photoreaction FKF1-LOV polypeptide was studied by low-temperature absorption spectroscopy. Upon blue light irradiation, ground state, D450, is converted to S390 known cysteinyl-flavin adduct intermediate photoreaction phototropin. Below 150 K,...

Phototropin (phot) is a blue-light sensor protein that elicits several photo responses in plants. has two flavin mononucleotide (FMN)-binding domains, LOV1 and LOV2, its N-terminal half. The C-terminal half blue-light-regulated Ser/Thr kinase. Various functional studies have reported only LOV2 responsible for the kinase activity, whereas X-ray crystallographic structures of domains are almost identical. How does such difference emerge? Our previous FTIR study LOV Adiantum neochrome1 (neo1)...

Phototropins (phot) are blue light receptors in plants which involved phototropism, stomatal opening, and chloroplast movements. Phototropin has two LOV domains (LOV1 LOV2), the LOV2 domain is responsible for activation of Ser/Thr kinase. There an alpha-helix at C-terminal side domain, called Jalpha helix. The functional importance helix been established Arabidopsis phot1, where light-induced structural perturbation takes place during photocycle domains. However, present FTIR study reports a...

Abstract Phototropin is a blue‐light photoreceptor in plants that mediates phototropism, chloroplast relocation, stomata opening and leaf expansion. molecule has two photoreceptive domains named LOV1 (light–oxygen–voltage) LOV2 the N‐terminus serine/threonine kinase domain C‐terminus, acts as blue light‐regulated kinase. Each LOV binds flavin mononucleotide chromophore undergoes unique cyclic reactions upon absorption comprises cysteinyl‐flavin adduct formation through triplet‐excited state...

The UV component of sunlight threatens all life on the earth by damaging DNA. photolyase (PHR) DNA repair proteins maintain genetic integrity harnessing blue light to restore intact bases from major UV-induced photoproducts, cyclobutane pyrimidine dimers (CPD), and (6–4) photoproducts ((6–4) PPs). PHR must catalyze not only covalent bond cleavage between two pyrmidine but also hydroxyl or amino group transfer 5′- 3′-pyrimidine base, requiring a more complex mechanism than that postulated for...

Ultraviolet (UV) light from the sun damages DNA by forming a cyclobutane pyrimidine dimer (CPD) and pyrimidine(6-4)pyrimidone photoproducts [(6-4) PP]. Photolyase (PHR) enzymes utilize near-UV/blue for repair, which is initiated light-induced electron transfer fully reduced flavin adenine dinucleotide chromophore. Despite similar structures repair mechanisms, functions of PHR are highly selective; CPD repairs CPD, but not (6-4) PP, vice versa. In this study, we attempted functional...

The primary photochemistry of the blue-light sensor protein, phototropin, is adduct formation between C4a atom flavin mononucleotide (FMN) chromophore and a nearby, reactive cysteine (Cys966), following decay triplet excited state FMN. distance position FMN sulfur Cys966 4.2 Å in LOV2 domain Adiantum neochrome 1 (neo1-LOV2), fusion protein phototropin containing phytochrome chromophoric domain. We previously reported presence an unreactive fraction neo1-LOV2 at low temperatures, which...

Phototropin is a blue-light sensor protein in plants, and LOV domain binds flavin mononucleotide (FMN) as chromophore. A photointermediate state, S390, formed by light-induced adduct formation between FMN an S-H group of nearby cysteine, which triggers structural changes for kinase activation phototropin. We previously studied the low-temperature Fourier transform infrared (FTIR) spectra S390 unphotolyzed states LOV2 phototropin from Adiantum (neo1-LOV2), found that structures intermediate...

Photolyases (PHRs) are blue light-activated DNA repair enzymes that maintain genetic integrity by reverting UV-induced photoproducts into normal bases. The flavin adenine dinucleotide (FAD) chromophore of PHRs has four different redox states: oxidized (FAD(ox)), anion radical (FAD(•-)), neutral (FADH(•)), and fully reduced (FADH(-)). We combined difference Fourier-transform infrared (FTIR) spectroscopy with UV-visible to study the detailed photoactivation process Xenopus (6-4) PHR. Two...

Photolyases (PHRs) are DNA repair proteins that revert UV-induced photoproducts, either cyclobutane pyrimidine dimers (CPD) or (6-4) photoproducts (PPs), into normal bases to maintain genetic integrity. The PHR must catalyze not only covalent bond cleavage but also hydroxyl amino group transfer, yielding a more complex mechanism than postulated for CPD PHR. Building upon recently established light-induced difference FTIR spectroscopy of Xenopus PHR, we now utilize 15N3′-labeled PP identify...

Photolyases (PHRs) utilize near UV/blue light to specifically repair the major photoproducts (PPs) of UV-induced damaged DNA. The cyclobutane pyrimidine dimer (CPD)-PHR binds flavin adenine dinucleotide (FAD) as a cofactor and repairs CPD lesions in double-stranded To understand activation mechanism CPD-PHR, we applied light-induced difference Fourier transform infrared (FTIR) spectroscopy whose signals were identified by use isotope-labeling. further investigate enzymatic function, here...

Observations of light-receptive enzyme complexes are usually complicated by simultaneous overlapping signals from the chromophore, apoprotein, and substrate, so that only initial, ultrafast, photon-chromophore reaction final, slow, protein conformational change provide separate, nonoverlapping signals. Each provides its own advantages, whereas sometimes intervening time scales still cannot be fully deconvoluted. We overcome problem using a novel method to selectively isotope-label apoprotein...

UV radiation triggers the formation of an adjacent pyrimidine lesion in DNA, pyrimidine(6-4)pyrimidone photoproduct ((6-4)PP). These lesions are cytotoxic and interfere with cell replication transcription, eventually inducing apoptosis, but they readily repaired by (6-4)photolyase. However, details repair mechanism have been debated. Here, we describe photorepair cycle, roles active site His365 His369 residues, robustness against mutation these residues. Using molecular dynamics simulations,...