Interleaflet Coupling of n-Alkane Incorporated Bilayers

Published

March 14, 2020

Author(s)

Hatsuho Usuda, Mafumi Hishida, Elizabeth Kelley, Yasuhisa Yamamura, Michihiro Nagao, Kazuya Saito

Abstract

The relationship between the membrane bending modulus (k) and compressibility modulus (KA) depends on the extent of coupling between the two monolayers (leaflets). Using neutron spin echo (NSE) spectroscopy, we investigate the effects of n-alkanes on the interleaflet coupling of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayers. Structural studies with small-angle X-ray and neutron scattering (SAXS and SANS) showed that the bilayer thickness increased with increasing n-alkane length, while NSE suggested that the bilayers become softer. Additional measurements of the membrane thickness fluctuations with NSE suggested that the changes in elastic moduli were due to a decrease in coupling for longer n-alkanes. The decreased coupling with elongating n-alkane length is explained based on the n-alkane distribution within the bilayers characterized by SANS measurement of bilayers composed of protiated DPPC and deuterated n-alkanes. A higher fraction of the incorporated long n-alkanes were concentrated at the central plane of the bilayers and decreased the physical interaction between the leaflets. Using NSE and SANS, we successfully correlated changes in the mesoscopic collective dynamics and microscopic membrane structure upon incorporation of n-alkanes.

Citation

Physical Chemistry Chemical Physics

Volume

22

Issue

10

Pub Type

Journals

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Keywords

lipid, bilayer, additives, elastic property, dynamics

Citation

Usuda, H. , Hishida, M. , Kelley, E. , Yamamura, Y. , Nagao, M. and Saito, K. (2020), Interleaflet Coupling of n-Alkane Incorporated Bilayers, Physical Chemistry Chemical Physics, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=929278 (Accessed December 13, 2024)