Phonon-mediated lipid raft formation in biological membranes

Dima Bolmatov, Jacob J. Kinnun, John Katsaras, Maxim O. Lavrentovich

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Short-wavelength collective molecular motions, also known as phonons, have recently attracted much interest in revealing dynamic properties of biological membranes through the use of neutron and X-ray scattering, infrared and Raman spectroscopies, and molecular dynamics simulations. Experimentally detecting unique vibrational patterns such as, shear phonon excitations, viscoelastic crossovers, transverse acoustic phonon gaps, and continuous and truncated optical phonon modes in cellular membranes, to name a few, has proven non-trivial. Here, we review recent advances in liquid thermodynamics that have resulted in the development of the phonon theory of liquids. The theory has important predictions regarding the shear vibrational spectra of fluids, namely the emergence of viscoelastic crossovers and transverse acoustic phonon gaps. Furthermore, we show that these vibrational patterns are common in soft (non-crystalline) materials, including, but not limited to liquids, colloids, liquid crystals (mesogens), block copolymers, and biological membranes. The existence of viscoelastic crossovers and acoustic phonon gaps define the self-diffusion properties of cellular membranes and provide a molecular picture of the transient nature of lipid rafts (Bolmatov et al., 2020). Importantly, the timescales (picoseconds) for the formation and dissolution of transient lipid rafts match the lifetime of the formation and breakdown of interfacial water hydrogen bonds. Apart from acoustic propagating phonon modes, biological membranes can also support more energetic non-propagating optical phonon excitations, also known as standing waves or breathing modes. Importantly, optical phonons can be truncated due to the existence of finite size nanodomains made up of strongly correlated lipid–cholesterol molecular pairs. These strongly coupled molecular pairs can serve as nucleation centers for the formation of stable rafts at larger length scales, due to correlations of spontaneous fluctuations (Onsager's regression hypothesis). Finally and importantly, molecular level viscoelastic crossovers, acoustic phonon gaps, and continuous and truncated optical phonon modes may offer insights as to how lipid–lipid and lipid–protein interactions enable biological function.

Original languageEnglish
Article number104979
JournalChemistry and Physics of Lipids
Volume232
DOIs
StatePublished - Oct 2020

Funding

J.J.K. is supported through the Scientific User Facilities Division of the Department of Energy (DOE) Office of Science, sponsored by the Basic Energy Science (BES) Program, DOE Office of Science, under Contract No. DEAC05-00OR22725.

FundersFunder number
Basic Energy Science
DOE Office of Science
U.S. Department of Energy
Office of ScienceDEAC05-00OR22725
Basic Energy Sciences

    Keywords

    • Acoustic and optical phonons
    • Collective lipid motions
    • Formation and dissolution of lipid rafts
    • Lipid self-diffusion
    • Strongly correlated lipid–cholesterol pairs
    • Transient lipid rafts

    Fingerprint

    Dive into the research topics of 'Phonon-mediated lipid raft formation in biological membranes'. Together they form a unique fingerprint.

    Cite this