Protein & Peptide Letters

Prof. Ben M. Dunn  
Department of Biochemistry and Molecular Biology
University of Florida
College of Medicine
P.O. Box 100245
Gainesville, FL
USA
Email: bdunn@ufl.edu

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Effect of the Compatible Solute Ectoine on the Stability of the Membrane Proteins

Author(s): Arpita Roychoudhury, Dieter Haussinger, Filipp Oesterhelt.

Abstract:

Mechanical single molecule techniques offer exciting possibilities for investigating protein folding and stability in native environments at sub-nanometer resolutions. Compatible solutes show osmotic activity which even at molar concentrations do not interfere with cell metabolism. They are known to protect proteins against external stress like temperature, high salt concentrations and dehydrating conditions. We studied the impact of the compatible solute ectoine (1M) on membrane proteins by analyzing the mechanical properties of Bacteriorhodopsin (BR) in its presence and absence by single molecule force spectroscopy. The unfolding experiments on BR revealed that ectoine decreases the persistence length of its polypeptide chain thereby increasing its tendency to coil up. In addition, we found higher unfolding forces indicating strengthening of those intra molecular interactions which are crucial for stability. This shows that force spectroscopy is well suited to study the effect of compatible solutes to stabilize membrane proteins against unfolding. In addition, it may lead to a better understanding of their detailed mechanism of action.

Keywords: Atomic force microscopy, membrane proteins, force spectroscopy, compatible solutes, ectoine, Microorganisms, heterocyclic amino acid, osmotic shocks, denaturation, protective substance

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Article Details

VOLUME: 19
ISSUE: 8
Year: 2012
Page: [791 - 794]
Pages: 4
DOI: 10.2174/092986612801619570