Abstract How polypeptide chains acquire specific conformations to realize unique biological functions is a central problem of protein science. Single-molecule spectroscopy, combined with fluorescence resonance energy transfer, utilized study the conformational heterogeneity and state-to-state transition dynamics proteins on submillisecond second timescales. However, observation microsecond timescale still very challenging. This important because elementary processes take place direct...

Representative methods of surface-selective phase-sensitive sum frequency generation spectroscopy are reviewed in terms interferometer implementation for optical heterodyne detection.

Elucidating the protein folding mechanism is crucial to understand how proteins acquire their unique structures realize various biological functions. With this aim, folding/unfolding of small globular has been extensively studied. Interestingly, recent studies have revealed that even such represent considerably complex processes. In study, we examined process a α-helical protein, B domain A (BdpA), at equilibrium using two-dimensional fluorescence lifetime correlation spectroscopy with 10 μs...

The χ(2) (second-order nonlinear optical susceptibility) spectrum of the water surface has been a matter debate for few decades. Here, we report that experimentally measured isotopic dilution dependence and theoretically reproduced it by employing quantum/classical mixed approach with new idea to subtract an artifact. present theoretical framework allows clarifying effects intramolecular, intermolecular, Fermi resonance couplings on OH-stretch vibrational spectra at as well in bulk.

We computed the IR, Raman, and sum frequency generation spectra of water in OH-stretch region by employing quantum/classical mixed approach that consists a vibrational spectroscopic map molecular dynamics (MD) simulation. carried out MD simulation with TIP4P, TIP4P/2005, TIP4P/Ice models applied designed for TIP4P Skinner et al. to each trajectory. Although is not tuned TIP4P-like models, TIP4P/2005 provide best reproduction experimental liquid crystalline ice, respectively. This result...

In view of the current situation in which OD-stretch vibrational spectra have been scarcely computed with non-polarizable rigid D2O models, we investigate IR and Raman by using a newly-reported model TIP4P/2005-HW. From comparison between calculations experimental data, find excellent performance TIP4P/2005-HW for spectroscopy same manner as TIP4P/2005 H2O, although one may still conveniently employ an alternative method that regards OH putative OD to calculate similar quality from...

Human serum albumin (HSA) plays important roles in transport of fatty acids and binding a variety drugs organic compounds the circulatory system. This protein experiences several conformational transitions by change pH, resulting conformations were essential for completing physiological vivo. Steady-state time-resolved fluorescence spectroscopy was applied to single tryptophan residue solely arranged HSA study subtle around at various pH. The results showed characteristic feature local...

A supported lipid bilayer (SLB) is a versatile platform for examining the dynamical properties of biomembranes. However, effect prerequisite solid substrate on dynamics SLB remains very elusive. Especially, it not clarified how diffusivity each leaflet in affected by SLB–solid interaction. In this study, we applied two-dimensional fluorescence lifetime correlation spectroscopy to elucidating diffusion lipids proximal and distal leaflets SLB. We find that autocorrelation curve fluorescent...

Abstract We present an experimental and theoretical study of Raman spectroscopy isotopically pure diluted amorphous as well crystalline ices at 30 K. Our experiments comprise polarized (VV) depolarized (VH) spectra in the OH‐stretch region, whereas our calculations involve molecular dynamics (MD) simulation high‐ low‐density through vitrification subsequent formulation vibrational Hamiltonian coupled OH oscillators hydrogen‐bond network ices. VV VH each isotopic dilution are good agreement...

The specific conformation of partially unfolded state beta-momorcharin was characterized through the steady-state and time-resolved fluorescence spectroscopic studies on a single Trp-190 which located adjacently to active site. content secondary structure retained, binding ANS remarkably enhanced, correlation time entire protein rotation prolonged at formed by being equilibrated with mild concentration guanidine hydrochloride. depolarization excitation energy transfer analysis suggest that...

The counting-rate dependence of the temporal response single photon avalanche diodes (SPADs) is a critical issue for accurate determination fluorescence lifetime. In this study, SPADs was examined with analyzing time interval detected photons. results clearly show that shift detection timing causes response, and solely determined by from preceding photon. We demonstrate instability readily calibrated utilizing macrotime data taken time-tag mode implemented in time-correlated counting modules.

Fluorescence lifetime correlation analysis is becoming a powerful tool to understand the conformational heterogeneity of biomolecules and their dynamics with an unprecedented detection sensitivity time resolution. However, its application study biomembranes very limited. Here, we report on two-dimensional fluorescence spectroscopy (2D FLCS) in combination total internal reflection (TIR) microscopy (TIR 2D-FLCS). High depth resolution TIR species-specific 2D FLCS give us opportunity...

In view of the current situation in which non-polarizable rigid water models have been scarcely examined against surface-specific properties, we appraise TIP4P-type at liquid surface on basis heterodyne-detected sum frequency generation (HD-SFG) spectroscopy. We find HD-SFG spectrum that peak hydrogen-bonded OH band, half width maximum and full free band are best reproduced by TIP4P, TIP4P/Ew, TIP4P/Ice, respectively, whereas it is already well known TIP4P/2005 reproduces tension. These...

Time-resolved fluorescence spectroscopy of tryptophan residue has been extensively applied to the studies on structure-function relationships protein. Regardless this, decay mechanism and kinetics in many proteins still remains unclear. Previous have demonstrated that conformational heterogeneity relaxation dynamics are both involved peculiar multiexponential subnanosecond resolution. In present study, we characterized property six indole compounds glycerol by resolving contribution...

We present standing evanescent-wave fluorescence correlation spectroscopy (SEW-FCS). This technique utilizes the interference of two evanescent waves which generates a evanescent-wave. Fringe-pattern illumination created by enables us to measure diffusion coefficients molecules with super-resolution corresponding one fringe width. Because width can be reliably estimated simple procedure, utilization fringes is beneficial quantitatively analyze slow in supported lipid bilayer (SLB), model...

We present an experimental and theoretical Raman spectroscopic study of isotopically pure diluted ice VI at 1 GPa room temperature. In the experiment, we measured OH-stretch spectra polycrystalline pressurized in a diamond anvil cell. also obtained as well Ih on basis molecular dynamics (MD) simulations map. find that are good agreement with data, which proves applicability accuracy map MD not only ambient condition but high pressure. particular, calculation successfully reproduces...

The unfolding of alpha-momorcharin was systematically investigated using steady-state and time-resolved tryptophan fluorescence, circular dichroism 8-anilino-1-naphthalenesulfonic acid (ANS) binding. These spectroscopic studies demonstrated that unfolded through a compact folded intermediate state. content alpha-helix increased, Trp192 approached closer to the side active site its rotational motion restricted by being equilibrated with 2-3 M guanidine hydrochloride. Furthermore, binding ANS...

Understanding the effect of a solid support on dynamical properties supported lipid bilayer (SLB) is prerequisite for applications SLB as model biomembrane. Here, we applied two-dimensional fluorescence lifetime correlation spectroscopy to examine solution pH diffusion lipids in proximal/distal leaflets zwitterionic SLB. Leaflet-specific analyses at various revealed that proximal leaflet facing glass surface becomes slower by decreasing with transition ∼7.4. We attributed it reduction charge...

A supported lipid bilayer (SLB) is now an indispensable tool to analyze the dynamical properties of biomembranes. However, effect a solid support on leaflet-specific dynamics in SLB remains elusive, which hampers further application as model biomembrane. Here, we performed diffusion analysis by means two-dimensional fluorescence lifetime correlation spectroscopy elucidate electrostatic interaction between headgroups and glass surface each leaflet SLB. The results clearly showed strength...

Cell membranes are fluidic, and the fluidic properties give unique biological functions to membranes. Here, we review application of fluorescence lifetime correlation analyses elucidate leaflet-specific lipid diffusion in a model cell membrane supported on glass surface. Utilization enables us discriminate signals from each leaflet bilayer analyze manner. The results showed that proximal facing surface is sensitive strength electrostatic interaction between headgroup whereas distal one...

The origin of multi-exponential fluorescence decay property tryptophan (Trp) in protein has been controversy, and dielectric relaxation is thought to be one the most plausible candidates that origin. In this study, we studied melittin–calmodulin interaction on concept by spectrally time-resolved spectroscopy. Trp residue melittin demonstrated drastic change its rate scale binding with calmodulin. Expected suggested accounts for decay. We also examined time variation radiative non-radiative...