Search results for "step-scan"

showing 3 items of 3 documents

Chromophore-Protein Interplay During the Phytochrome Photocycle Revealed by Step-Scan FTIR Spectroscopy

2018

Phytochrome proteins regulate many photoresponses of plants and microorganisms. Light absorption causes isomerization of the biliverdin chromophore, which triggers a series of structural changes to activate the signaling domains of the protein. However, the structural changes are elusive, and therefore the molecular mechanism of signal transduction remains poorly understood. Here, we apply two-color step-scan infrared spectroscopy to the bacteriophytochrome from Deinococcus radiodurans. We show by recordings in H2O and D2O that the hydrogen bonds to the biliverdin D-ring carbonyl become disordered in the first intermediate (Lumi-R) forming a dynamic microenvironment, then completely detach …

0301 basic medicineInfrared spectroscopyMolecular Dynamics SimulationBiochemistryCatalysis03 medical and health scienceschemistry.chemical_compoundchromophore-protein interplayColloid and Surface ChemistryBacterial ProteinsSpectroscopy Fourier Transform InfraredPeptide bondta116BiliverdinbiologyPhytochromeHydrogen bondBiliverdineta1182WaterHydrogen BondingDeinococcus radioduransGeneral ChemistryChromophorePhotochemical Processesbiology.organism_classification030104 developmental biologychemistryBiophysicsProtein Conformation beta-StrandDeinococcusPhytochromevalokemiaproteiinitSignal transductionstep-scan FTIR spectroscopyAdenylyl CyclasesJournal of the American Chemical Society
researchProduct

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy

2014

Monitoring the dynamics of protonation and protein backbone conformation changes during the function of a protein is an essential step towards understanding its mechanism. Protonation and conformational changes affect the vibration pattern of amino acid side chains and of the peptide bond, respectively, both of which can be probed by infrared (IR) difference spectroscopy. For proteins whose function can be repetitively and reproducibly triggered by light, it is possible to obtain infrared difference spectra with (sub)microsecond resolution over a broad spectral range using the step-scan Fourier transform infrared technique. With -10(2)-10(3) repetitions of the photoreaction, the minimum num…

RhodopsinMaterials scienceproton transferProtein ConformationGeneral Chemical EngineeringBiophysicsAnalytical chemistryInfrared spectroscopymembrane proteinsProtonationtime-resolved spectroscopyGeneral Biochemistry Genetics and Molecular Biologychannelrhodopsinattenuated total reflectionProtein structureSpectroscopy Fourier Transform InfraredFourier transform infrared spectroscopyinfrared spectroscopySpectroscopyIssue 88biologyGeneral Immunology and MicrobiologybacteriorhodopsinGeneral Neurosciencesingular value decompositionstep-scanProteinsEspectroscòpia infrarojaBacteriorhodopsinPhotochemical ProcessesBacteriorhodopsinsAttenuated total reflectionprotein dynamicsbiology.proteinProtonsTime-resolved spectroscopyProteïnesJournal of Visualized Experiments
researchProduct

Spin Crossover and Long-Lived Excited States in a Reduced Molecular Ruby.

2020

Abstract The chromium(III) complex [CrIII(ddpd)2]3+ (molecular ruby; ddpd=N,N′‐dimethyl‐N,N′‐dipyridine‐2‐yl‐pyridine‐2,6‐diamine) is reduced to the genuine chromium(II) complex [CrII(ddpd)2]2+ with d4 electron configuration. This reduced molecular ruby represents one of the very few chromium(II) complexes showing spin crossover (SCO). The reversible SCO is gradual with T 1/2 around room temperature. The low‐spin and high‐spin chromium(II) isomers exhibit distinct spectroscopic and structural properties (UV/Vis/NIR, IR, EPR spectroscopies, single‐crystal XRD). Excitation of [CrII(ddpd)2]2+ with UV light at 20 and 290 K generates electronically excited states with microsecond lifetimes. This…

step-scan IR spectroscopychemistry.chemical_element010402 general chemistryPhotochemistry01 natural sciencesCatalysislaw.inventionChromiumSpin crossoverlawSpin CrossoverElectron paramagnetic resonanceexcited states010405 organic chemistryChemistryCommunicationOrganic ChemistryGeneral ChemistryCommunications0104 chemical sciencesMicrosecondExcited stateElectron configurationchromiummagnetic propertiesExcitationChemistry (Weinheim an der Bergstrasse, Germany)
researchProduct