Folding and Lipid Composition Determine Membrane Interaction of the Disordered Protein COR15A.

摘要: Plants from temperate climates, such as the model plant Arabidopsis thaliana, are challenged with seasonal low temperatures that lead to increased freezing tolerance in fall a process termed cold acclimation. Among other adaptations, this involves accumulation of cold-regulated (COR) proteins, intrinsically disordered chloroplast-localized protein COR15A. Together its close homolog COR15B, it stabilizes chloroplast membranes during freezing. COR15A folds into amphipathic α-helices presence high concentrations low-molecular-mass crowders or upon dehydration. Under these conditions, (partially) folded binds peripherally membranes. In our study, we have used coarse-grained molecular dynamics simulations elucidate details COR15A-membrane binding and effects on membrane structure dynamics. Simulation results indicate at least partial folding highly unsaturated galactolipids necessary for efficient binding. The bound is stabilized by interactions charged polar amino acids galactolipid headgroups hydrophobic upper part fatty acyl chains. Experimentally, liposomes made mixture lipids mimicking induces additional under conditions dehydration, agreement simulation results.