1 Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA 2 Department of Physics, Indian Institute of Science, Bangalore, India 3 Department of Physics, University of Arizona, Tucson, AZ, USA Soohyun K. Lee 1 , Trivikram R. Molugu 1 , K.J. Mallikarjunaiah 1,2 , Michael F. Brown 1,3 Elastic Deformation And Collective Dynamics in Lipid Membranes: A Solid-state 2 H NMR Relaxation Study BPS platform talk 2016 3/1/2016, 4:00 PM
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Biomembranes platform talk for the annual Biophysical Society Meeting 2016
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1Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA 2Department of Physics, Indian Institute of Science, Bangalore, India
3Department of Physics, University of Arizona, Tucson, AZ, USA
Soohyun K. Lee1, Trivikram R. Molugu1, K.J. Mallikarjunaiah1,2, Michael F. Brown1,3
Elastic Deformation And Collective Dynamics in Lipid Membranes: A Solid-state 2H
NMR Relaxation Study
BPS platform talk 20163/1/2016, 4:00 PM
J.J. Kinnun et al. (2015) BBA 1848, 246
How Does Hydration Affect Lipid Membranes And
Dynamics?
How Does Hydration Affect Lipid Membranes And Dynamics?
Parsegian: X-ray diffraction - bilayer thickness increases with decrease in water level
Nagle: X-ray diffraction and diatometry Gawrisch: X-ray diffraction and infrared
measurements – bilayer thickness also changes with polyunsaturated lipids
Mallikarjunaiah: Solid-state 2H NMR - bilayer thickness is very sensitive to the hydration levels
Lets examine the membrane from the dynamics standpoint!
K.J. Mallikarjunaiah et al. (2011) Biophys. J. 100, 98
• Introduction to solid-state 2H NMR experiments
• Model-free interpretation of lipid relaxation data
• Collective lipid dynamics
• Hydration-induced slow dynamics
• Conclusions
Outline of the Talk
J.J. Kinnun et al. (2015) BBA 1848, 246K.J. Mallikarjunaiah et al. (2011) Biophys. J. 100, 98
• Introduction to solid-state 2H NMR experiments
• Model-free interpretation of lipid relaxation data
• Collective lipid dynamics
• Hydration-induced slow dynamics
• ConclusionsJ.J. Kinnun et al. (2015) BBA 1848, 246K.J. Mallikarjunaiah et al. (2011) Biophys. J. 100, 98
Outline of the Talk
• Line shape measurements– Reveal motional amplitudes– Gives structural information
like in X-ray crystallography• Relaxation measurements– Depends on motional
amplitudes and rates– Informative on molecular
motions over a wide frequency range
Solid-state 2H NMR Experiments Are Done in Two Ways
A. Leftin et al. (2014) eMagRes 3, 199X. Xu et al. (2014) eMagRes 3, 275
• Line shape measurements– Reveal motional amplitudes– Gives structural information
like in X-ray crystallography• Relaxation measurements– Depends on motional
amplitudes and rates– Informative on molecular
motions over a wide frequency range
Solid-state 2H NMR Experiments Are Done in Two Ways
A. Leftin et al. (2014) eMagRes 3, 199X. Xu et al. (2014) eMagRes 3, 275
A. Leftin, M.F. Brown (2011) BBA 1808, 818
Solid-state 2H NMR Gives Site-resolved Information for Bilayers
J.J. Kinnun et al. (2015) BBA 1848, 246
Solid-state 2H NMR Gives Site-resolved Information for Bilayers
Closure Property of Reference Frames in Solid-state 2H NMR Experiment
A. Leftin et al. (2014) eMagRes 3, 199X. Xu et al. (2014) eMagRes 3, 275
A. Leftin et al. (2013) JMB 425, 2973A. Leftin et al. (2011) BBA 1808, 818
Hierarchy of Membrane Dynamics
Molecular motions near the Larmor frequency contribute to Relaxation NMR relaxation methods are suitable to probe such dynamics.
Motions Collective Motions
(b)
(c)
NMR Relaxation Experiments(a)
Quadrupolar echo-T2
T1 inversion recovery
CPMG-T2
A. Leftin et al. (2011) BBA 1808, 818X. Xu et al. (2014) eMagRes 3, 275
• Introduction to solid-state 2H NMR experiments
• Model-free interpretation of lipid relaxation data
• Collective lipid dynamics
• Hydration-induced slow dynamics
• Conclusions
Outline of the Talk
J.J. Kinnun et al. (2015) BBA 1848, 246K.J. Mallikarjunaiah et al. (2011) Biophys. J. 100, 98
Model-free Interpretation of Lipid Relaxation Data
Gateway to discoveries on membrane motions
Relaxation Measurements Are Related to Quasi-elastic
Properties
• D is the viscoelastic property, the lower the stiffer (Viscosity is and K is the elastic constant)
• The linear dependence is due to the slow collective dynamics• Assumptions are that the sample is large vesicles and motions are of
bilayer dimension
X. Xu et al. (2014) eMagRes 3, 275
G.V. Martinez et al. Phys. Rev. E (2002) 66 050902
M.F. Brown (1984) JCP 80, 2832A.A. Nevzorov & M.F. Brown (1997) JCP 107, 10288