title: Progressive ordering with decreasing temperature of the phospholipids of influenza virus.
abstract: Using linewidth and spinning sideband intensities of lipid hydrocarbon chain resonances in proton magic angle spinning NMR spectra, we detected the temperature-dependent phase state of naturally occurring lipids of intact influenza virus without exogenous probes. Increasingly, below 41 degrees C ordered and disordered lipid domains coexisted for the viral envelope and extracts thereof. At 22 degrees C much lipid was in a gel phase, the fraction of which reversibly increased with cholesterol depletion. Diffusion measurements and fluorescence microscopy independently confirmed the existence of gel-phase domains. Thus the existence of ordered regions of lipids in biological membranes is now demonstrated. Above the physiological temperatures of influenza infection, the physical properties of viral envelope lipids, regardless of protein content, were indistinguishable from those of the disordered fraction. Viral fusion appears to be uncorrelated to ordered lipid content. Lipid ordering may contribute to viral stability at lower temperatures, which has recently been found to be critical for airborne transmission.
authors.affiliation: Laboratory of Cellular and Molecular Biophysics, National Institute of Child Health and Human Development, 10D14, 10 Center Drive MSC 1855, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: Ivan V
authors.initials: IV
authors.lastname: Polozov
authors.forename: Ludmila
authors.initials: L
authors.lastname: Bezrukov
authors.forename: Klaus
authors.initials: K
authors.lastname: Gawrisch
authors.forename: Joshua
authors.initials: J
authors.lastname: Zimmerberg
mesh_terms: D009682:Magnetic Resonance Spectroscopy / Q000379:methods / Q000592:standards; D008563:Membrane Lipids / Q000737:chemistry*; D021962:Membrane Microdomains / Q000737:chemistry*; D008567:Membranes, Artificial; D008856:Microscopy, Fluorescence; D009975:Orthomyxoviridae / Q000737:chemistry*; D010316:Particle Size; D010743:Phospholipids / Q000737:chemistry*; D012015:Reference Standards; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D053586:Virus Internalization
chemical_list: D008563:Membrane Lipids; D008567:Membranes, Artificial; D010743:Phospholipids; C050629:viral envelope lipids