title: The role of membrane properties in Mistic folding and dimerisation.
abstract: Membranes not only provide cellular compartmentalization but influence protein behavior and folding by virtue of the multitude of different lipid types. We have studied the impact of lipid composition on the folding of the membrane-associated protein Mistic from B. subtilis. We use dimerisation via the single Cys3 residue as monitor for the degree of correct folding, since mis- or unfolding will expose the otherwise buried Cys3. We find great variability in how lipids affect protein production and dimerization, ranging from high production and low dimerization via increased production and higher dimerization to low production and low dimerization. Phosphocholine (PC) vesicles, in particular di-oleoyl-PC, lead to the highest production levels. Shorter chain lengths lead to reduced production but higher levels of dimerization. Different lipids may promote correct folding of Mistic to different extents, mediated by proper hydrophobic matching (attained for long-chain but not short-chain PC vesicles) and the existence of a fluid phase (the gel phase reduces production as well as dimerization, probably by immobilizing Mistic on the surface). The very fact that different lipids have an effect indicates that Mistic behaves like a bona fide membrane protein with a clear preference for membranes of a certain thickness and flexibility.
authors.affiliation: Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology, University of Aarhus, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark.
authors.forename: Dilip K
authors.initials: DK
authors.lastname: Debnath
authors.forename: Rajiv Vaid
authors.initials: RV
authors.lastname: Basaiawmoit
authors.forename: Kåre Lehmann
authors.initials: KL
authors.lastname: Nielsen
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Otzen
mesh_terms: D001412:Bacillus subtilis / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D008081:Liposomes / Q000737:chemistry; D008563:Membrane Lipids / Q000737:chemistry*; D008565:Membrane Proteins / Q000737:chemistry*; D008958:Models, Molecular; D010713:Phosphatidylcholines / Q000737:chemistry; D017510:Protein Folding; D055503:Protein Multimerization
chemical_list: D001426:Bacterial Proteins; D008081:Liposomes; D008563:Membrane Lipids; D008565:Membrane Proteins; D010713:Phosphatidylcholines; C017251:1,2-oleoylphosphatidylcholine