Abstract
Functional protein motions covering a wide range of time scales can be studied, among other techniques, by NMR and by molecular dynamics (MD) computer simulations. MD simulations of proteins now routinely extend into the hundreds of nanoseconds time scale range exceeding the overall tumbling correlation times of proteins in solution by several orders of magnitude. This provides a unique opportunity to rigorously validate these simulations by quantitative comparison with model-free order parameters derived from NMR relaxation experiments. However, presently there is no consensus on how such a comparison is best done. We address here how this can be accomplished in a way that is both efficient and objective. For this purpose, we analyze (15)N R1 and R2 and heteronuclear {(1)H}-(15)N NOE NMR relaxation parameters computed from 500 ns MD trajectories of 10 different protein systems using the model-free analysis. The resulting model-free S(2) order parameters are then used as targets for S(2) values computed directly from the trajectories by the iRED method by either averaging over blocks of variable lengths or by using exponentially weighted snapshots (wiRED). We find that the iRED results are capable of reproducing the target S(2) values with high accuracy provided that the averaging window is chosen 5 times the length of the overall tumbling correlation time. These results provide useful guidelines for the derivation of NMR order parameters from MD for a meaningful comparison with their experimental counterparts.
[NMR paper] General Order Parameter based Correlation Analysis of Protein Backbone Motions between Experimental NMR Relaxation Measurements and Molecular Dynamics Simulations.
General Order Parameter based Correlation Analysis of Protein Backbone Motions between Experimental NMR Relaxation Measurements and Molecular Dynamics Simulations.
Related Articles General Order Parameter based Correlation Analysis of Protein Backbone Motions between Experimental NMR Relaxation Measurements and Molecular Dynamics Simulations.
Biochem Biophys Res Commun. 2015 Jan 16;
Authors: Liu Q, Shi C, Yu L, Zhang L, Xiong Y, Tian C
Abstract
Internal backbone dynamic motions are essential for different protein functions and...
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01-21-2015 08:39 PM
General Order Parameter based Correlation Analysis of Protein Backbone Motions between Experimental NMR Relaxation Measurements and Molecular Dynamics Simulations
General Order Parameter based Correlation Analysis of Protein Backbone Motions between Experimental NMR Relaxation Measurements and Molecular Dynamics Simulations
Publication date: Available online 16 January 2015
Source:Biochemical and Biophysical Research Communications</br>
Author(s): Qing Liu , Chaowei Shi , Lu Yu , Longhua Zhang , Ying Xiong , Changlin Tian</br>
Internal backbone dynamic motions are essential for different protein functions and occur on a wide range of time scales, from femtoseconds to seconds. Molecular dynamic (MD) simulations and...
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01-17-2015 04:14 PM
Time-averaged order parameter restraints in molecular dynamics simulations
Time-averaged order parameter restraints in molecular dynamics simulations
Abstract
A method is described that allows experimental \(S^2\) order parameters to be enforced as a time-averaged quantity in molecular dynamics simulations. The two parameters that characterize time-averaged restraining, the memory relaxation time and the weight of the restraining potential energy term in the potential energy function used in the simulation, are systematically investigated...
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10-14-2014 09:48 PM
Rotational velocity rescaling of molecular dynamics trajectories for direct prediction of protein NMR relaxation
Rotational velocity rescaling of molecular dynamics trajectories for direct prediction of protein NMR relaxation
July 2012
Publication year: 2012
Source:Biophysical Chemistry, Volumes 168–169</br>
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Rotational velocity rescaling (RVR) enables 15N relaxation data for the anisotropically tumbling B3 domain of Protein G (GB3) to be accurately predicted from 1?s of constant energy molecular dynamics simulation without recourse to any system-specific adjustable parameters. Superposition of adjacent trajectory frames yields the unique rotation axis and angle of rotation...
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02-03-2013 10:13 AM
[NMR paper] Defining long range order in NMR structure determination from the dependence of heter
Defining long range order in NMR structure determination from the dependence of heteronuclear relaxation times on rotational diffusion anisotropy.
Related Articles Defining long range order in NMR structure determination from the dependence of heteronuclear relaxation times on rotational diffusion anisotropy.
Nat Struct Biol. 1997 Jun;4(6):443-9
Authors: Tjandra N, Garrett DS, Gronenborn AM, Bax A, Clore GM
Structure determination by NMR presently relies on short range restraints between atoms in close spatial proximity, principally in the...
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08-22-2010 03:31 PM
[NMR paper] Defining long range order in NMR structure determination from the dependence of heter
Defining long range order in NMR structure determination from the dependence of heteronuclear relaxation times on rotational diffusion anisotropy.
Related Articles Defining long range order in NMR structure determination from the dependence of heteronuclear relaxation times on rotational diffusion anisotropy.
Nat Struct Biol. 1997 Jun;4(6):443-9
Authors: Tjandra N, Garrett DS, Gronenborn AM, Bax A, Clore GM
Structure determination by NMR presently relies on short range restraints between atoms in close spatial proximity, principally in the...
Refinement against order parameter with XPLOR
New 2.10 release of XPLOR-NIH can now do a refinement against order parameters. You can get an idea what this refinement can be used for from the this paper.
Info about new features of XPLOR-NIH 2.10 from XPLOR-NIH website: - new parameter/topology file naming convention: NMR protein refinement should now use topology file protein.top and parameter file protein.par.
- new command: tclXplor which calls xplor -tcl. Can be used as command interpreter
- new potential term OrderPot to enable refinement against order parameters.
- update to PrePot from Junji Iwahara
- CSAPot: 15N CSAs...