A Digital rf Pulse Burst Generator for NMR Relaxation Experiments

1970 ◽  
Vol 41 (12) ◽  
pp. 1766-1770 ◽  
Author(s):  
V. Radeka ◽  
R. L. Chase ◽  
M. Petrinovic ◽  
J. A. Glasel
2012 ◽  
Vol 40 (2) ◽  
pp. 419-423 ◽  
Author(s):  
Mikael Akke

Protein conformational dynamics can be critical for ligand binding in two ways that relate to kinetics and thermodynamics respectively. First, conformational transitions between different substates can control access to the binding site (kinetics). Secondly, differences between free and ligand-bound states in their conformational fluctuations contribute to the entropy of ligand binding (thermodynamics). In the present paper, I focus on the second topic, summarizing our recent results on the role of conformational entropy in ligand binding to Gal3C (the carbohydrate-recognition domain of galectin-3). NMR relaxation experiments provide a unique probe of conformational entropy by characterizing bond-vector fluctuations at atomic resolution. By monitoring differences between the free and ligand-bound states in their backbone and side chain order parameters, we have estimated the contributions from conformational entropy to the free energy of binding. Overall, the conformational entropy of Gal3C increases upon ligand binding, thereby contributing favourably to the binding affinity. Comparisons with the results from isothermal titration calorimetry indicate that the conformational entropy is comparable in magnitude to the enthalpy of binding. Furthermore, there are significant differences in the dynamic response to binding of different ligands, despite the fact that the protein structure is virtually identical in the different protein–ligand complexes. Thus both affinity and specificity of ligand binding to Gal3C appear to depend in part on subtle differences in the conformational fluctuations that reflect the complex interplay between structure, dynamics and ligand interactions.


1998 ◽  
Vol 283 (1) ◽  
pp. 221-229 ◽  
Author(s):  
Christian Renner ◽  
Roland Baumgartner ◽  
Angelika A Noegel ◽  
Tad A Holak

2006 ◽  
Vol 36 (2) ◽  
pp. 79-102 ◽  
Author(s):  
Tianzhi Wang ◽  
Daniel S. Weaver ◽  
Sheng Cai ◽  
Erik R. P. Zuiderweg

2017 ◽  
Vol 69 (3) ◽  
pp. 133-146 ◽  
Author(s):  
Pavel Srb ◽  
Jiří Nováček ◽  
Pavel Kadeřávek ◽  
Alžbeta Rabatinová ◽  
Libor Krásný ◽  
...  

Author(s):  
Falk Hoffmann ◽  
Frans A. A. Mulder ◽  
Lars V. Schäfer

Solution-state NMR relaxation experiments are the cornerstone to study internalprotein dynamics at atomic resolution on time scales that are faster than the overallrotational tumbling time,τR. Since the motions described by NMR relaxation pa-rameters are connected to thermodynamic quantities like conformational entropies, thequestion arises how much of the total entropy is contained within this tumbling time.Using all-atom molecular dynamics (MD) simulations of T4 lysozyme, we found thatentropy build-up is rather fast for the backbone, such that the majority of the entropyis indeed contained in the short-time dynamics. In contrast, the contribution of slowdynamics of side chains on time scales beyondτRon the side chain conformationalentropy is significant and should be taken into account for the extraction of accuratethermodynamic properties.


1982 ◽  
Vol 37 (5-6) ◽  
pp. 394-398 ◽  
Author(s):  
Georges J. Béné ◽  
Bernard Borcard ◽  
Volker Graf ◽  
Emile Hiltbrand ◽  
Patric Magnin ◽  
...  

Abstract In order to show that for a possible application in medical diagnosis NMR-relaxation experiments at low Larmor frequencies (v0 ≤ 20 kHz) are more sensitive than the up to now done high field measurements in the MHz-range, we present dispersion curves (v0 = 50 Hz to 50 MHz) of the proton longitudinal relaxation time T1 and values of the transversal relaxation time T2 for the example of amniotic fluids. Only for Larmor frequencies below ≃ 100 kHz the relaxation times for healthy amniotic fluid and pathological meconium solutions are significantly different, whereas at high Larmor frequencies, i. e. in the conventional MHz-range, the observed changes are rather small.


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