title: Importance of hydrophobic matching for spontaneous insertion of a single-spanning membrane protein.
abstract: In this study, we have investigated the effect of hydrophobic mismatch between the thickness of the membrane and a transmembrane segment of a protein that directly inserts into the membrane bilayer. For this purpose we used mutants of the single-spanning Pf3 coat protein that can spontaneously insert into Escherichia coli membrane vesicles and large unilamellar vesicles (LUVs). The thickness of the liposomal bilayer could be altered by using lipids with different acyl chain lengths or by incorporation of cholesterol. The insertion efficiency of the protein clearly depended on the bilayer thickness, with most efficient insertion under hydrophobic matching conditions. To discriminate between effects of length and hydrophobicity, mutants with different synthetic transmembrane segments were constructed. These mutants inserted into LUVs in a mismatch-dependent manner. However, in particular for longer and less hydrophobic mutants, most efficient insertion was generally observed in thinner bilayers than expected on the basis of hydrophobic matching.
authors.affiliation: Department of Biochemistry of Membranes, Centre for Biomembranes and Lipid Enzymology, Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands. a.n.j.a.ridder@chem.uu.nl
authors.forename: Anja N J A
authors.initials: AN
authors.lastname: Ridder
authors.forename: Wessel
authors.initials: W
authors.lastname: van de Hoef
authors.forename: Jeanette
authors.initials: J
authors.lastname: Stam
authors.forename: Andreas
authors.initials: A
authors.lastname: Kuhn
authors.forename: Ben
authors.initials: B
authors.lastname: de Kruijff
authors.forename: J Antoinette
authors.initials: JA
authors.lastname: Killian
mesh_terms: D000595:Amino Acid Sequence; D002213:Capsid / Q000737:chemistry* / Q000378:metabolism; D036022:Capsid Proteins; D019286:Endopeptidase K / Q000378:metabolism; D007700:Kinetics; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D020449:Repetitive Sequences, Amino Acid
chemical_list: D036022:Capsid Proteins; D008051:Lipid Bilayers; D008565:Membrane Proteins; D011994:Recombinant Proteins; C084332:major coat protein, Pseudomonas phage Pf3; D019286:Endopeptidase K