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Title: Dynamics of crowding-induced mixing in phase separated lipid bilayers

We use fluorescence microscopy to examine the dynamics of the crowding-induced mixing transition of liquid ordered (L o)–liquid disordered (L d) phase separated lipid bilayers when the following particles of increasing size bind to either the L o or L d phase: Ubiquitin, green fluorescent protein (GFP), and nanolipoprotein particles (NLPs) of two diameters. These proteinaceous particles contained histidine-tags, which were phase targeted by binding to iminodiacetic acid (IDA) head groups, via a Cu 2+ chelating mechanism, of lipids that specifically partition into either the Lo phase or Ld phase. The degree of steric pressure was controlled by varying the size of the bound particle (10–240 kDa) and the amount of binding sites present (i.e., DPIDA concentrations of 9 and 12 mol%) in the supported lipid multibilayer platform used here. We develop a mass transfer-based diffusional model to analyze the observed L o phase domain dissolution that, along with visual observations and activation energy calculations, provides insight into the sequence of events in crowding-induced mixing. Furthermore, our results suggest that the degree of steric pressure and target phase influence not only the efficacy of steric-pressure induced mixing, but the rate and controlling mechanism for which it occurs.
Authors:
 [1] ;  [1] ;  [2] ;  [1] ;  [1]
  1. Univ. of California, Davis, CA (United States)
  2. Sandia National Lab. (SNL-CA), Livermore, CA (United States)
Publication Date:
Report Number(s):
SAND-2016-7155J
Journal ID: ISSN 1520-6106; 646062
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry
Additional Journal Information:
Journal Volume: 120; Journal Issue: 43; Journal ID: ISSN 1520-6106
Publisher:
American Chemical Society
Research Org:
Sandia National Lab. (SNL-CA), Livermore, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1335132

Zeno, Wade F., Johnson, Kaitlin E., Sasaki, Darryl Y., Risbud, Subhash H., and Longo, Marjorie L.. Dynamics of crowding-induced mixing in phase separated lipid bilayers. United States: N. p., Web. doi:10.1021/acs.jpcb.6b07119.
Zeno, Wade F., Johnson, Kaitlin E., Sasaki, Darryl Y., Risbud, Subhash H., & Longo, Marjorie L.. Dynamics of crowding-induced mixing in phase separated lipid bilayers. United States. doi:10.1021/acs.jpcb.6b07119.
Zeno, Wade F., Johnson, Kaitlin E., Sasaki, Darryl Y., Risbud, Subhash H., and Longo, Marjorie L.. 2016. "Dynamics of crowding-induced mixing in phase separated lipid bilayers". United States. doi:10.1021/acs.jpcb.6b07119. https://www.osti.gov/servlets/purl/1335132.
@article{osti_1335132,
title = {Dynamics of crowding-induced mixing in phase separated lipid bilayers},
author = {Zeno, Wade F. and Johnson, Kaitlin E. and Sasaki, Darryl Y. and Risbud, Subhash H. and Longo, Marjorie L.},
abstractNote = {We use fluorescence microscopy to examine the dynamics of the crowding-induced mixing transition of liquid ordered (Lo)–liquid disordered (Ld) phase separated lipid bilayers when the following particles of increasing size bind to either the Lo or Ld phase: Ubiquitin, green fluorescent protein (GFP), and nanolipoprotein particles (NLPs) of two diameters. These proteinaceous particles contained histidine-tags, which were phase targeted by binding to iminodiacetic acid (IDA) head groups, via a Cu2+ chelating mechanism, of lipids that specifically partition into either the Lo phase or Ld phase. The degree of steric pressure was controlled by varying the size of the bound particle (10–240 kDa) and the amount of binding sites present (i.e., DPIDA concentrations of 9 and 12 mol%) in the supported lipid multibilayer platform used here. We develop a mass transfer-based diffusional model to analyze the observed Lo phase domain dissolution that, along with visual observations and activation energy calculations, provides insight into the sequence of events in crowding-induced mixing. Furthermore, our results suggest that the degree of steric pressure and target phase influence not only the efficacy of steric-pressure induced mixing, but the rate and controlling mechanism for which it occurs.},
doi = {10.1021/acs.jpcb.6b07119},
journal = {Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry},
number = 43,
volume = 120,
place = {United States},
year = {2016},
month = {10}
}