Realistic cell envelopes
The detailed lipid organization of cellular membranes remains elusive. A typical plasma membrane (PM) contains hundreds of different lipid species and the cell carefully regulates its composition. Specific organisms often synthesize thousands of different lipid types and currently over 30,000 biologically relevant lipids have been identified. Why do organisms create and maintaining such a large diversity of lipids when maintaining bilayer barrier properties and solvating membrane proteins only require a few? What are the roles of all these lipids and how do these diverse lipids interact and organize?
To start to address these questions we have optimized and added to the Martini CG FF lipidome. Systematically explored lipid bulk properties of over a hundred different lipid types (e.g. bilayer thickness, area per lipid, diffusion, order parameter and area compressibility). Using the extensive Martini lipid library we created an idealized plasma membranes containing dozens of different lipid types asymmetrically distributed between the membrane leaflets and explored it in multi-microsecond time scale simulations , as demonstrated in the figure below. These PM simulations provide a high-resolution view on the complex PM lipid organization and have allowed us to analyze a variety of PM physicochemical properties, including: lipid-lipid interactions, bilayer bulk material properties, domain formation and coupling between the bilayer leaflets. Revealing a global non-ideal mixing of different lipid species at different spatiotemporal scales . Ongoing work in the Molecular Dynamics group and with our collaborators is shedding light on how changes in PM composition effects overall membrane properties, how complex lipid mixtures interact with membrane proteins and the organization of other cell envelopes.
 H.I. Ingólfsson, M.N. Melo, F.J. van Eerden, C. Arnarez, C.A. López, T.A. Wassenaar, X. Periole, A.H. De Vries, D.P. Tieleman, S.J. Marrink. Lipid organization of the plasma membrane. JACS, 36:14554-14559, 2014.
|Last modified:||25 June 2015 01.52 a.m.|