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Melting transitions in biomembranes.

Authors
  • Mužić, Tea1
  • Tounsi, Fatma1
  • Madsen, Søren B1
  • Pollakowski, Denis1
  • Konrad, Manfred2
  • Heimburg, Thomas3
  • 1 Membrane Biophysics Group, Niels Bohr Institute, University of Copenhagen, Denmark. , (Denmark)
  • 2 Max-Planck-Institute for Biophysical Chemistry, Am Fassberg 11, Göttingen 37077, Germany. , (Germany)
  • 3 Membrane Biophysics Group, Niels Bohr Institute, University of Copenhagen, Denmark. Electronic address: [email protected] , (Denmark)
Type
Published Article
Journal
Biochimica et biophysica acta. Biomembranes
Publication Date
Nov 01, 2019
Volume
1861
Issue
11
Pages
183026–183026
Identifiers
DOI: 10.1016/j.bbamem.2019.07.014
PMID: 31465764
Source
Medline
Keywords
Language
English
License
Unknown

Abstract

We investigated melting transitions in native biological membranes containing their membrane proteins. The membranes originated from E. coli, B. subtilis, lung surfactant and nerve tissue from the spinal cord of several mammals. For some preparations, we studied the pressure, pH and ionic strength dependence of the transition. For porcine spine, we compared the transition of the native membrane to that of the extracted lipids. All preparations displayed melting transitions of 10-20° below physiological or growth temperature, independent of the organism of origin and the respective cell type. We found that the position of the transitions in E. coli membranes depends on the growth temperature. We discuss these findings in the context of the thermodynamic theory of membrane fluctuations close to transition that predicts largely altered elastic constants, an increase in fluctuation lifetime and in membrane permeability. We also discuss how to distinguish lipid melting from protein unfolding transitions. Since the feature of a transition slightly below physiological temperature is conserved even when growth conditions change, we conclude that the transitions are likely to be of major biological importance for the survival and the function of the cell. Copyright © 2019 Elsevier B.V. All rights reserved.

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