A novel NMR method is demonstrated for the investigation of protein ligand interactions. In this approach an adiabatic fast passage pulse, i.e. a long, weak pulse with a linear frequency sweep, is used to probe (1)H-(1)H NOEs. During the adiabatic fast passage the effective rotating-frame NOE is a weighted average of transverse and longitudinal cross-relaxation contributions that can be tuned by pulse power and frequency sweep rate. It is demonstrated that the occurrence of spin diffusion processes leads to sizable deviations from the theoretical relationship between effective relaxation rate and effective tilt angle in the spin lock frame and can be used to probe protein-ligand binding. This methodology comprises high sensitivity and ease of implementation. The feasibility of this technique is demonstrated with two protein complexes, vanillic acid bound to the quail lipocalin Q83 and NAD(+) and AMP binding to alcohol dehydrogenase (ADH).
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http://dx.doi.org/10.1021/ja910098s | DOI Listing |
J Chem Phys
January 2025
Division of Energy, Matter and Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, Missouri 64110, USA.
Developing efficient path integral (PI) methods for atomistic simulations of vibrational spectra in heterogeneous condensed phases and interfaces has long been a challenging task. Here, we present the h-CMD method, short for hybrid centroid molecular dynamics, which combines the recently introduced fast quasi-CMD (f-QCMD) method with fast CMD (f-CMD). In this scheme, molecules that are believed to suffer more seriously from the curvature problem of CMD, e.
View Article and Find Full Text PDFJ Chem Phys
November 2024
Center for Life Nano Science @Sapienza, Istituto Italiano di Tecnologia, 295 Viale Regina Elena, I-00161 Roma, Italy.
Polymers (Basel)
October 2024
Departament de Física de la Matèria Condensada (FMC), Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Catalonia, Spain.
We study the enhancement of the elastocaloric effect in natural rubber by using forced air convection to favour heat extraction during the elongation stage of a stretching-unstretching cycle. Elastocaloric performance is quantified by means of the adiabatic undercooling that occurs after fast removal of the stress, measured by infrared thermography. To ensure accuracy, spatial averaging on thermal maps of the sample surface is performed since undercooled samples display heterogeneities caused by various factors.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
February 2025
State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China.
Conformational dynamics has been well observed in the 3s Rydberg state of amines, whereas its observation in higher-energy, non-equilibrium 3p Rydberg states is very rare, especially for a reversible conformational transition that could compete with other non-adiabatic transitions. Herein, we report the observation of a reversible conformational interconversion phenomenon in the 3p Rydberg excited-state dynamics of N,N-dimethylethylamine (DMEA). Upon electronic excitation, a forward and backward interconversion between the initially prepared 3p_l and 3p_h conformers accompanied by 3p internal conversions occurs, resulting in a 3p_l/3p_h equilibrium ratio of 61 %/39 % within ∼1.
View Article and Find Full Text PDFPhys Rev Lett
September 2024
Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, 01187 Dresden, Germany.
Periodically driven systems have emerged as a useful technique to engineer the properties of quantum systems, and are in the process of being developed into a standard toolbox for quantum simulation. An outstanding challenge that leaves this toolbox incomplete is the manipulation of the states dressed by strong periodic drives. The state-of-the-art in Floquet control is the adiabatic change of parameters.
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