10.5061/DRYAD.FFBG79CTK
Hayes, Douglas
0000-0003-0303-1411
University of Tennessee at Knoxville
Anunciado, Divina
Oak Ridge National Laboratory
Ye, Ran
University of Tennessee System
Williams, Rachel
Oak Ridge National Laboratory
O'Neill, Hugh
Oak Ridge National Laboratory
Pingali, Sai Venkatesh
Oak Ridge National Laboratory
Urban, Volker
Oak Ridge National Laboratory
Circular dichroism spectroscopic and small-angle neutron scattering
analysis of alpha-synuclein and bacteriorhodopsin in bicontinuous
microemulsions
Dryad
dataset
2021
FOS: Chemical engineering
Oak Ridge National Laboratory
https://ror.org/01qz5mb56
LDRD Grant 6552
2021-07-14T00:00:00Z
2021-07-14T00:00:00Z
en
https://doi.org/10.1002/jsde.12500
901733 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
The membrane proteins (MPs) alpha-synuclein (ASYN) and bacteriorhodopsin
(BR) were readily incorporated into bicontinuous microemulsions (BMEs)
formed by two microemulsion systems: water/heptane/Aerosol-OT
(AOT)/CK-2,13 and water/dodecane/sodium dodecyl sulfate (SDS)/1-pentanol.
(CK-2,13 is an alkyl ethoxylate possessing two alkyl tail groups of carbon
chain length 2 and 13 and an average degree of ethoxylation of 5.6.) MPs
were encapsulated in BMEs through preparation of Winsor-III systems at
optimal salinity, with the anionic surfactants AOT and SDS providing the
driving force for extraction. Dissolution of ASYN in BMEs greatly
increased the former’s alpha-helicity, similar to ASYN’s behavior in the
presence of biomembranes, while BME- and vesicle-encapsulated BR possessed
similar secondary structure. Small-angle neutron scattering (SANS) results
clearly demonstrated the direct interaction of MPs with the surfactants,
resulting in a decrease of surface area per volume for surfactant
monolayers due to decreased surfactant efficiency. The SANS signal for
ASYN was isolated through the use of neutron contrast matching for the
surfactants through partial deuteration of water and oil, one of the first
reports of contrast matching for BMEs in the literature. The SANS results
of the contrast matched sample reflected similar aggregation for ASYN in
BMEs as was reported previously for vesicles and SDS solution. This study
demonstrates the potential use of BMEs as MP host systems for conducting
biochemical reactions such as the conversion of sunlight into adenosine
triphosphate (ATP) by BR and studying fundamental behavior of MPs, such as
the role of ASYN dysfunction in Parkinson’s disease, as well as for
isolation and purification of MPs via Winsor-III -based extraction.
Circular dichroism spectroscopic data reported herein was obtained
directly from the instrument. The CONTIN program was used to fit the
spectroscopic data, to obtain an estimate of the distribution of secondary
structure for the proteins. Small-angle neutron scattering (SANS) data
provided herein was obtained from the Bio-SANS instrument at Oak Ridge
National Laboratory (Oak Ridge, TN, USA), and reduced and processed in a
standard fashion. Microsoft Excel was employed to obtain linear fits to
SANS data, as described in the spreadsheets and readme file.