title: An 18 amino acid amphiphilic helix forms the membrane-anchoring domain of the Escherichia coli penicillin-binding protein 5.
abstract: Small (10 residue) C-terminal deletions of PBP5 cause release of this inner membrane protein into the periplasm, indicating disruption of the membrane binding domain. To define the extent of the membrane anchoring domain, oligonucleotide-directed mutagenesis was used to introduce both single amino acid changes and novel restriction sites into the DNA, allowing subsequent construction of precise internal deletions. The 10 C-terminal amino acid residues possess very weak membrane anchoring potential. By extending the sequence to 18 residues membrane binding equivalent to that of authentic PBP5 was achieved. A proline substitution in this region, breaking a potential alpha-helix, also disrupts the membrane binding domain. These results are discussed with respect to the amphiphilicity of the C-terminal sequence when arranged in an alpha-helix.
authors.affiliation: Department of Biochemistry, University of Liverpool, UK.
authors.forename: M E
authors.initials: ME
authors.lastname: Jackson
authors.forename: J M
authors.initials: JM
authors.lastname: Pratt
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D002872:Chromosome Deletion; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D005796:Genes; D005798:Genes, Bacterial; D006602:Hexosyltransferases; D008969:Molecular Sequence Data; D002267:Muramoylpentapeptide Carboxypeptidase / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D046915:Penicillin-Binding Proteins; D010406:Penicillins / Q000378:metabolism*; D010458:Peptidyl Transferases; D011487:Protein Conformation
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D046915:Penicillin-Binding Proteins; D010406:Penicillins; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase