Precise Control of Neutron Contrast in Surfactant Micelles Provides Platform for Membrane Structure Studies

Detergent Micelles
The scattering collected for detergent at its solution match point, where contrast still persists between core and shell, produces a non-flat scattering profile (red). Incorporating the non-ionic detergent DDM with deuterium-labelled chains allows matching of the core and shell contrast, producing the flat scattering profile shown in blue. [Reprinted with permission from Oliver, R. C., S. V. Pingali, and V. S. Urban. “Designing Mixed Detergent Micelles for Uniform Neutron Contrast.” J. Phys. Chem. Lett. 8, 5041–5046 (2017). [DOI: 10.1021/acs.jpclett.7b02149]. Copyright 2017 American Chemical Society.]
Scientists in this study have successfully demonstrated the ability to manipulate the neutron contrast of detergent micelles by incorporating a similar detergent with deuterium-labelled alkyl chains. The presence of excess detergent micelle scattering often has a detrimental influence on scattering data obtained for membrane protein–detergent complexes. Isolation of the scattering signal from the protein of interest can be accomplished by eliminating all scattering from the detergent. Using this approach enabled determination of the overall structure and oligomeric state of a small membrane protein enzyme.

Oliver, R. C., et al. “Designing Mixed Detergent Micelles for Uniform Neutron Contrast.” The Journal of Physical Chemistry Letters 8(20), 5041–5046 (2017). [DOI:10.1021/acs.jpclett.7b02149].

Instruments and Facilities Used: Small angle neutron scattering (SANS): Bio-SANS beamline (CG3) of the High-Flux Isotope Reactor at Oak Ridge National Laboratory (ORNL). Recorded scattering data using MantidPlot software. Neutron contrast studies: ModULes for the Analysis of Contrast (MULCh) Variation Data at University of Sydney (smb-research.smb.usyd.edu.au/NCVWeb/).

Funding Acknowledgements: Neutron scattering studies at CG-3 Bio-SANS instrument at the High-Flux Isotope Reactor (HFIR), Oak Ridge National Laboratory (ORNL), sponsored by the Office of Biological and Environmental Research (OBER) and Office of Basic Energy Sciences (OBES) Scientific User Facilities Division (SUF), U.S. Department of Energy (DOE) Office of Science. Work benefited from use of the SasView application, originally developed under National Science Foundation (NSF) Award DMR-0520547. SasView contains code developed with funding from the European Union’s Horizon 2020 Research and Innovation Programme under the SINE2020 project, Grant Agreement No 654000. Manuscript authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with DOE. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan).

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