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Photochemistry and Photobiology

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https://www.readbyqxmd.com/read/27925276/conformational-and-intermolecular-interaction-dynamics-of-photolyase-cryptochrome-proteins-monitored-by-the-time-resolved-diffusion-technique
#1
Masato Kondoh, Masahide Terazima
Cryptochrome (CRY), a blue light sensor protein, possesses a similar domain structure to photolyase (PHR) that, upon absorption of light, repairs DNA damage. In this review, we compare the reaction dynamics of these systems by monitoring the reaction kinetics of conformation change and intermolecular interaction change based on time-dependent diffusion coefficient measurements obtained by using the pulsed laser-induced transient grating technique. Using this method, time-dependent biomolecular interactions, such as transient dissociation reactions in solution, have been successfully detected in real time...
December 7, 2016: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/27925224/fluorescent-protein-photoprotein-fusions-and-their-applications-in-calcium-imaging
#2
Adil Bakayan, Beatriz Domingo, Cecilia F Vaquero, Nadine Peyriéras, Juan Llopis
Calcium-activated photoproteins, such as aequorin, have been used as luminescent Ca(2+) indicators since 1967. After the cloning of aequorin in 1985, microinjection was substituted by its heterologous expression, which opened the way for a widespread use. Molecular fusion of GFP to aequorin recapitulated the nonradiative energy transfer process that occurs in the jellyfish Aequorea victoria, from which these two proteins were obtained, resulting in an increase of light emission and a shift to longer wavelength...
December 7, 2016: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/27925218/insights-into-light-driven-dna-repair-by-photolyases-challenges-and-opportunities-for-electronic-structure-theory
#3
Shirin Faraji, Andreas Dreuw
UV radiation causes two of the most abundant mutagenic and cytotoxic DNA lesions: cyclobutane pyrimidine dimers and 6-4 photoproducts. (6-4) photolyases are light-activated enzymes that selectively bind to DNA and trigger repair of mutagenic 6-4 photoproducts via photoinduced electron transfer from flavin adenine dinucleotide anion (FADH(-) ) to the lesion triggering repair. This review provides an overview of the sequential steps of the repair process, i.e. light absorption and resonance energy transfer, photo-induced electron transfer, and electron-induced splitting mechanisms, with an emphasis on the role of theory and computation...
December 7, 2016: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/27925216/light-regulation-of-alternative-pre-mrna-splicing-in-plants
#4
Hangxiao Zhang, Chentao Lin, Lianfeng Gu
Alternative splicing (AS) is a major post-transcriptional mechanism to enhance the diversity of proteome in response to environmental signals. Among the numerous external signals perceived by plants, light is the most crucial one. Plants utilize complex photoreceptor signaling networks to sense different light conditions and adjust their growth and development accordingly. Although light-mediated gene expression has been widely investigated, little is known regarding the mechanism of light affecting AS to modulate mRNA at the post-transcriptional level...
December 7, 2016: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/27891621/animal-cryptochromes-divergent-roles-in-light-perception-circadian-timekeeping-and-beyond
#5
Alicia K Michael, Jennifer L Fribourgh, Russell N Van Gelder, Carrie L Partch
Cryptochromes are evolutionarily related to the light-dependent DNA repair enzyme photolyase, serving as major regulators of circadian rhythms in insects and vertebrate animals. There are two types of cryptochromes in the animal kingdom: Drosophila-like CRYs that act as non-visual photopigments linking circadian rhythms to the environmental light/dark cycle, and vertebrate-like CRYs that do not appear to sense light directly, but control the generation of circadian rhythms by acting as transcriptional repressors...
November 28, 2016: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/27891613/a-review-of-spectroscopic-and-biophysical-chemical-studies-of-the-complex-of-cpd-photolyase-and-cryptochrome-dash-with-substrate-dna
#6
Johannes P M Schelvis, Yvonne M Gindt
CPD photolyase (PL) is a structure-specific DNA repair enzyme that uses blue light to repair cyclobutane pyrimidine dimers (CPD) on DNA. Cryptochrome (CRY) DASH enzymes use blue light for the repair of CPD lesions on single-stranded (ss) DNA, though some may also repair these lesions on double-stranded (ds) DNA. In addition, CRY DASH may be involved in blue-light signaling, similar to cryptochromes. The focus of this review is on spectroscopic and biophysical chemical experiments of the enzyme-substrate complex that have contributed to a more detailed understanding of all the aspects of the CPD repair mechanism of CPD photolyase and CRY DASH...
November 28, 2016: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/27864885/phylogenetic-and-functional-classification-of-the-photolyase-cryptochrome-family
#7
Nuri Ozturk
The Photolyase/Cryptochrome (PHR/CRY) family is a large group of proteins with similar structure and but very diverge functions such as in DNA repair, circadian clock resetting, and regulation of transcription. As a result of advances in the biochemistry of the CRY/PHR family and identification of new members, several adjustments have been made to the classification of this protein family. For example, a new class of PHRs, Class III, has been proposed. Furthermore, CRYs have been suggested to function as photosensory proteins in the primordial eye of sponge larvae...
November 19, 2016: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/27864884/mfd-protein-and-transcription-repair-coupling-in-e-coli
#8
Christopher P Selby
In 1989, transcription-repair coupling (TRC) was first described in Escherichia coli, as the transcription-dependent, preferential nucleotide excision repair (NER) of UV photoproducts located in the template DNA strand. This finding led to pioneering biochemical studies of TRC in the laboratory of Professor Aziz Sancar, where, at the time, major contributions were being made toward understanding the roles of the UvrA, UvrB and UvrC proteins in NER. When the repair studies were extended to TRC, template but not coding strand lesions were found to block RNA polymerase (RNAP) in vitro, and unexpectedly, the blocked RNAP inhibited NER...
November 19, 2016: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/27861975/convergence-of-the-nobel-fields-of-telomere-biology-and-dna-repair
#9
Elise Fouquerel, Patricia Opresko
The fields of telomere biology and DNA repair have enjoyed a great deal of cross-fertilization and convergence in recent years. Telomeres function at chromosome ends to prevent them from being falsely recognized as chromosome breaks by the DNA damage response and repair machineries. Conversely, both canonical and non-conical functions of numerous DNA repair proteins have been found to be critical for preserving telomere structure and function. In 2009 Elizabeth Blackburn, Carol Greider, and Jack Szostak were awarded the Nobel prize in Physiology or Medicine for the discovery of telomeres and telomerase...
November 18, 2016: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/27861974/solving-blue-light-riddles-new-lessons-from-flavin-binding-lov-photoreceptors
#10
Aba Losi, Wolfgang Gärtner
Detection of blue light (BL) via flavin-binding photoreceptors (Fl-Blues) has evolved throughout all three domains of life. Although the main BL players, i.e. LOV (Light, Oxygen and Voltage), BLUF (Blue Light Sending using Flavins) and Cry (Cryptochrome) proteins have been characterized in great detail with respect to structure and function, still several unresolved issues at different levels of complexity remain and novel unexpected findings were reported. Here, we review the most prevailing riddles of LOV-based photoreceptors, for example: the relevance of water and/or small metabolites for the dynamics of the photocycle; molecular details of light-to-signal transduction events; the interplay of BL sensing by LOV domains with other environmental stimuli, such as BL plus oxygen mediating photodamage and its impact on microbial life-styles; the importance of the cell or chromophore redox state in determining the fate of BL-driven reactions; the evolutionary pathways of LOV-based BL sensing and associated functions through the diverse phyla...
November 18, 2016: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/27861963/cation-and-anion-substituted-potassium-manganese-phosphate-kmnp3-o9-luminescence-and-photocatalytic-studies
#11
C H Sudhakar Reddy, G Ravi, K Sreenu, Ravinder Guje, M Malathi, Muga Vithal
Phosphates as multi-functional materials were of vital importance in the environmental and energy fields. In the present work, a new cyclophosphate, potassium-manganese-phosphate (KMnP3 O9 ) (hereafter KMPO), was prepared by solid state method. Cations (Ag(+) and Cu(2+) ) and anion (N(3-) ) were substituted into KMPO lattice via ion-exchange and solid state methods respectively. The as-prepared materials were characterized by powder X-ray diffraction, SEM-EDS and UV-visible diffuse reflectance spectra. Rietveld refinement was carried out for parent material...
November 18, 2016: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/27861940/cloning-of-the-orange-light-producing-luciferase-from-photinus-scintillans-a-new-proposal-on-how-bioluminescence-color-is-determined
#12
Bruce R Branchini, Tara L Southworth, Danielle M Fontaine, Martha H Murtiashaw, Alex McGurk, Munya H Talukder, Rakhshi Qureshi, Deniz Yetil, Jesse A Sundlov, Andrew M Gulick
Unlike the enchanting yellow-green flashes of light produced on warm summer evenings by Photinus pyralis, the most common firefly species in North America, the orange lights of Photinus scintillans are infrequently observed. These Photinus species, and likely all bioluminescent beetles, use the same substrates beetle luciferin, ATP, and oxygen to produce light. It is the structure of the particular luciferase enzyme that is the key to determining the color of the emitted light. We report here the molecular cloning of the P...
November 18, 2016: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/27861980/bringing-it-all-together-coupling-excision-repair-to-the-dna-damage-checkpoint
#13
Laura A Lindsey-Boltz
Nucleotide excision repair and the ATR-mediated DNA damage checkpoint are two critical cellular responses to the genotoxic stress induced by ultraviolet (UV) light and are important for cancer prevention. In vivo genetic data indicate that these global responses are coupled. Aziz Sancar and colleagues developed an in vitro coupled repair-checkpoint system to analyze the basic steps of these DNA damage stress responses in a biochemically defined system. The minimum set of factors essential for repair-checkpoint coupling include damaged DNA, the excision repair factors (XPA, XPC, XPF-ERCC1, XPG, TFIIH, RPA), the 5'-3' exonuclease EXO1, and the damage checkpoint proteins ATR-ATRIP and TopBP1...
November 14, 2016: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/27861959/the-cartography-of-uv-induced-dna-damage-formation-and-dna-repair
#14
Jinchuan Hu, Sheera Adar
DNA damage present a barrier to DNA-templated biochemical processes, including gene expression and faithful DNA replication. Compromised DNA repair leads to mutations, enhancing the risk for genetic diseases and cancer development. Conventional experimental approaches to study DNA damage required a researcher to choose between measuring bulk damage over the entire genome, with little or no resolution regarding a specific location, and obtaining data specific to a locus of interest, without a global perspective...
November 14, 2016: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/27861953/a-novel-streptavidin-luciferase-fusion-protein-preparation-properties-and-application-in-hybridization-analysis-of-dna
#15
D V Smirnova, M Y Rubtsova, V G Grigorenko, N N Ugarova
A streptavidin-luciferase fusion protein comprising the thermostable mutant form of firefly luciferase Luciola mingrelica and minimal core streptavidin was constructed. The streptavidin-luciferase fusion was mainly produced in a tetrameric form with high luciferase and biotin-binding activities. It was shown, that fusion has the same Km values for ATP and luciferin and the bioluminescence spectra as initial luciferase. The linear dependence of the bioluminescence signal on the content of the fusion was observed within the range of 10(-18) -10(-13) mol per well...
November 14, 2016: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/27861972/cryptochromes-orchestrate-transcription-regulation-of-diverse-blue-light-responses-in-plants
#16
Zhaohe Yang, Bobin Liu, Jun Su, Jiakai Liao, Chentao Lin, Yoshito Oka
Blue light affects many aspects of plant growth and development throughout the plant lifecycle. Plant cryptochromes (CRYs) are UV-A/blue light photoreceptors that play pivotal roles in regulating blue light-mediated physiological responses via the regulated expression of more than one thousand genes. Photoactivated CRYs regulate transcription via two distinct mechanisms: indirect promotion of the activity of transcription factors by inactivation of the COP1/SPA E3 ligase complex or direct activation or inactivation of at least two sets of basic helix-loop-helix transcription factor families by physical interaction...
November 12, 2016: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/27861966/improving-the-photocatalytic-activity-of-modified-anatase-tio2-with-different-concentrations-of-aluminum-under-visible-light-mechanistic-survey
#17
Shahrara Afshar, Shabnam Pordel, Babak Tahmouresilerd, Alireza Azad
Visible-light-driven Al-doped TiO2 with different aluminum contents (2, 5, and 10 mol %) were synthesized via a facile sol-gel method. Fourier transform infrared (FTIR), UV-visible diffuse reflectance, energy dispersive X-ray (EDX) spectroscopy as well as X-ray diffraction (XRD), X-ray fluorescence (XRF) and scanning electron microscopy (SEM) methods were used for the characterization of the obtained nanoparticles. The photocatalytic performance of the samples was evaluated by the degradation of rhodamine B (RhB) under visible light irradiation...
November 12, 2016: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/27861965/impact-of-the-circadian-clock-on-uv-induced-dna-damage-response-and-photocarcinogenesis
#18
Panshak Dakup, Shobhan Gaddameedhi
The skin is in constant exposure to various external environmental stressors, including solar ultraviolet (UV) radiation. Various wavelengths of UV light are absorbed by the DNA and other molecules in the skin to cause DNA damage and induce oxidative stress. The exposure to excessive ultraviolet (UV) radiation and/or accumulation of damage over time can lead to photocarcinogenesis and photoaging. The nucleotide excision repair (NER) system is the sole mechanism for removing UV photoproduct damage from DNA, and genetic disruption of this repair pathway leads to the photosensitive disorder xeroderma pigmentosum (XP)...
November 12, 2016: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/27861964/unanimous-model-for-describing-the-fast-bioluminescence-kinetics-of-ca-2-regulated-photoproteins-of-different-organisms
#19
Elena V Eremeeva, Sergey I Bartsev, Willem J H van Berkel, Eugene S Vysotski
Upon binding their metal ion cofactors, Ca(2+) -regulated photoproteins display a rapid increase of light signal, which reaches its peak within milliseconds. In the present study we investigate bioluminescence kinetics of the entire photoprotein family. All five recombinant hydromedusan Ca(2+) -regulated photoproteins-aequorin from Aequorea victoria, clytin from Clytia gregaria, mitrocomin from Mitrocoma cellularia, and obelins from Obelia longissima and Obelia geniculata-demonstrate the same bioluminescent kinetics pattern...
November 12, 2016: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/27859304/from-mfd-to-trcf-and-back-again-a-perspective-on-bacterial-transcription-coupled-nucleotide-excision-repair
#20
Alexandra M Deaconescu, Margaret M Suhanovsky
Photochemical and other reactions on DNA cause damage and corrupt genetic information. To counteract this damage, organisms have evolved intricate repair mechanisms that often crosstalk with other DNA-based processes, such as transcription. Intriguing observations in the late 1980s and early 1990s led to the discovery of transcription-coupled repair (TCR), a subpathway of nucleotide excision repair (NER). TCR, found in all domains of life prioritizes for repair lesions located in the transcribed DNA strand, directly read by RNA polymerase...
November 12, 2016: Photochemistry and Photobiology
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