title: Transmembrane helix assembly and the role of salt bridges.
abstract: Transmembrane helix-helix interactions mediate the folding and assembly of membrane proteins. Recognition motifs range from GxxxG and leucine zippers to polar side chains and salt bridges. Some canonical membrane proteins contain local charge clusters that are important for folding and function, and which have to be compatible with a stable insertion into the bilayer via the translocon. Recently, the electrostatic "charge zipper" has been described as another kind of assembly motif. The protein sequences exhibit a quasi-symmetrical pattern of complementary charges that can form extended ladders of salt bridges. Such segments can insert reversibly into membranes, or even translocate across them. Nature uses charge zippers in transport processes, and they can also be adapted in the design of cell-penetrating carriers.
authors.affiliation: Karlsruhe Institute of Technology (KIT), Institute of Biological Interfaces (IBG2) and Institute of Organic Chemistry, Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany.
authors.forename: Torsten H
authors.initials: TH
authors.lastname: Walther
authors.affiliation: Karlsruhe Institute of Technology (KIT), Institute of Biological Interfaces (IBG2) and Institute of Organic Chemistry, Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany. Electronic address: anne.ulrich@kit.edu.
authors.forename: Anne S
authors.initials: AS
authors.lastname: Ulrich
mesh_terms: D002462:Cell Membrane / Q000737:chemistry*; D006801:Humans; D006860:Hydrogen Bonding; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics; D015202:Protein Engineering; D017433:Protein Structure, Secondary; D055672:Static Electricity
chemical_list: D008565:Membrane Proteins