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Biophysics of Proteins at Surfaces: Assembly, Activation, Signaling
Thursday Speaker Abstracts
High Resolution Imaging Atomic Force Microscope Study of Interactions at the
Membrane-Fluid Interface
Chiara Rotella
1,2
, Jason I. Kilpatrick
2
, Simona Capponi
1,2
, Miguel Holmgren
3
, Francisco
Bezanilla
4
, Eduardo Perozo
4
, Suzanne P. Jarvis
1,2
.
1
School of Physics, University College Dublin, Dublin, Ireland,
2
Conway Institute of
Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland,
3
Molecular
Neurophysiology Section, Porter Neuroscience Research Center, National Institute of Health,
Bethesda, MD, USA,
4
Department of Biochemistry and Molecular Biology, The University of
Chicago, Chicago, IL, USA.
The cell membrane is essential for all living systems, serving as a barrier between cells
and their environment. It is typically composed of a lipid bilayer, containing embedded and/or
anchored proteins that mediate different biological function such as energy conversion, signal
transduction and solute transport [1]. To elucidate the basic structure of biological membranes it
is necessary to make direct experimental observations of the molecular organization of the
protein and lipid bilayer under physiologically relevant conditions. Using a bespoke high
resolution Atomic Force Microscopy (AFM) it is possible to characterize the structure and
function of both native and model lipid membranes with embedded proteins [2].
During this study we focus our attention on transmembrane MvP voltage-gated potassium
channels embedded in a lipid bilayer, which are activated by changes in transmembrane potential
[3]. High resolution AFM images of the membrane channel reveal the predicted tetrameric
channel structure of the ion channel. Interestingly, we observed the formation of an asymmetric
depression in the supporting lipid membrane surrounding the channel. This may be due to an
alteration in the lipid bilayer structure to accommodate the ion channel. Using AFM is possible
to investigate the interactions between proteins and membrane- liquid interface [4], [5] aiding
our understanding and leading to future therapeutic application.
References
[1] D. J. Muller et al.,
Nature protocols
, vol. 2, no. 9, pp. 2191--2197,
2007
.
[2] A. Sumino et al.,
Scientific reports
, vol. 3,
2013
.
[3] A. M. Randich et al.,
Biochemistry
, vol. 53, pp. 1627--1636,
2014
.
[4] K. H. Sheikh and S. P. Jarvis,
Journal of the American Chemical Society
, vol. 133, pp.
18296--18303,
2011
.
[5] U. M. Feber et al.,
Eur Biophys
, vol. 40, pp. 329-338,
2011
.