Cholesterol-Induced Conformational Change in the Sphingomyelin Headgroup

Shinya Hanashima, Kazuhiro Murakami, Michihiro Yura, Yo Yano, Yuichi Umegawa, Hiroshi Tsuchikawa, Nobuaki Matsumori, Sangjae Seo, Wataru Shinoda, Michio Murata

Research output: Contribution to journalArticle

Abstract

Sphingomyelin (SM) and cholesterol (Cho) are the important lipids for the formation of biologically functional membrane domains, lipid rafts. However, the interaction between Cho and the headgroup of SM remains unclear. In this study, we performed solid-state NMR experiments to reveal the Cho effects on the headgroup conformation using 2H-labeled stearoyl-SM (SSM). Deuterated SSMs at the Cα, Cβ, and Cγ positions of a choline moiety were separately prepared and subjected to NMR measurements to determine the quadrupolar splitting of 2H signals in hydrated SSM unitary and SSM/Cho (1:1) bilayers. Using 2H NMR and 13C-31P REDOR data, the conformation and orientation of the choline moiety were deduced and compared with those derived from molecular dynamics simulations. In SSM unitary bilayers, three torsional angles in the phosphocholine moiety, P-O-Cα-Cβ, were found to be consecutive +gauche(g)/+g/+g or −g/−g/−g. The orientation and conformation of the SSM headgroup were consistent with the results of our molecular dynamics simulations and the previous results on phosphatidylcholines. The quadrupolar coupling at the α methylene group slightly increased in the presence of Cho, and those at the Cβ and Cγ decreased more significantly, thus suggesting that Cho reduced the gauche conformation at the Cα-Cβ torsion. The conformational ensemble in the presence of Cho may enhance the so-called umbrella effect of the SSM headgroup, resulting in the stabilization of Cho near the SM molecules by concealing the hydrophobic Cho core from interfacial water. We also examined the effect of the chiral centers at the sphingosine chain to the headgroup conformation by determining the enantiomeric excess between the diastereomeric +g/+g/+g and −g/−g/−g conformers using (S)-Cα-deuterated and (R)-Cα-deuterated SSMs. Their 2H NMR measurements showed that the chiral centers induced the slight diastereomeric excess in the SM headgroup conformation.

Original languageEnglish
Pages (from-to)307-318
Number of pages12
JournalBiophysical Journal
Volume117
Issue number2
DOIs
Publication statusPublished - Jul 23 2019

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Sphingomyelins
Cholesterol
Molecular Dynamics Simulation
Choline
Sphingosine
Phosphorylcholine
Membrane Lipids
Phosphatidylcholines
Lipids
Water

All Science Journal Classification (ASJC) codes

  • Biophysics

Cite this

Hanashima, S., Murakami, K., Yura, M., Yano, Y., Umegawa, Y., Tsuchikawa, H., ... Murata, M. (2019). Cholesterol-Induced Conformational Change in the Sphingomyelin Headgroup. Biophysical Journal, 117(2), 307-318. https://doi.org/10.1016/j.bpj.2019.06.019

Cholesterol-Induced Conformational Change in the Sphingomyelin Headgroup. / Hanashima, Shinya; Murakami, Kazuhiro; Yura, Michihiro; Yano, Yo; Umegawa, Yuichi; Tsuchikawa, Hiroshi; Matsumori, Nobuaki; Seo, Sangjae; Shinoda, Wataru; Murata, Michio.

In: Biophysical Journal, Vol. 117, No. 2, 23.07.2019, p. 307-318.

Research output: Contribution to journalArticle

Hanashima, S, Murakami, K, Yura, M, Yano, Y, Umegawa, Y, Tsuchikawa, H, Matsumori, N, Seo, S, Shinoda, W & Murata, M 2019, 'Cholesterol-Induced Conformational Change in the Sphingomyelin Headgroup', Biophysical Journal, vol. 117, no. 2, pp. 307-318. https://doi.org/10.1016/j.bpj.2019.06.019
Hanashima S, Murakami K, Yura M, Yano Y, Umegawa Y, Tsuchikawa H et al. Cholesterol-Induced Conformational Change in the Sphingomyelin Headgroup. Biophysical Journal. 2019 Jul 23;117(2):307-318. https://doi.org/10.1016/j.bpj.2019.06.019
Hanashima, Shinya ; Murakami, Kazuhiro ; Yura, Michihiro ; Yano, Yo ; Umegawa, Yuichi ; Tsuchikawa, Hiroshi ; Matsumori, Nobuaki ; Seo, Sangjae ; Shinoda, Wataru ; Murata, Michio. / Cholesterol-Induced Conformational Change in the Sphingomyelin Headgroup. In: Biophysical Journal. 2019 ; Vol. 117, No. 2. pp. 307-318.
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