Conformational transmission in condensed lipid model compounds

Abstract

On changing the phosphorus coordination from four to five via a trigonal bipyramidal geometry in phospholipid model systems, a conformational change is initiated around the C2-C3 linkage caused by enhanced electrostatic repulsion between the atoms 0 3 and 0 2 , situated in the axis of the trigonal bipyramid. This is supported by the absence ofconformational change upon substitution of 0 2 by methylene. With solid-state cross-polarization and magic-angle spinning 13C-NMR it is shown that such a conformational transmission leads to an increased packing density of the lipid chains. It seems to us that changes in lipid packing caused by conformational transmission may also occur when pentacoordination is present transiently, as under biological conditions, thereby inducing an activation of the transport proteins that are embedded in the membrane.