title: Disulfide isomerization after membrane release of its SAR domain activates P1 lysozyme.
abstract: The P1 lysozyme Lyz is secreted to the periplasm of Escherichia coli and accumulates in an inactive membrane-tethered form. Genetic and biochemical experiments show that, when released from the bilayer, Lyz is activated by an intramolecular thiol-disulfide isomerization, which requires a cysteine in its N-terminal SAR (signal-arrest-release) domain. Crystal structures confirm the alternative disulfide linkages in the two forms of Lyz and reveal dramatic conformational differences in the catalytic domain. Thus, the exported P1 endolysin is kept inactive by three levels of control-topological, conformational, and covalent-until its release from the membrane is triggered by the P1 holin.
authors.affiliation: Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128, USA.
authors.forename: Min
authors.initials: M
authors.lastname: Xu
authors.forename: Arockiasamy
authors.initials: A
authors.lastname: Arulandu
authors.forename: Douglas K
authors.initials: DK
authors.lastname: Struck
authors.forename: Stephanie
authors.initials: S
authors.lastname: Swanson
authors.forename: James C
authors.initials: JC
authors.lastname: Sacchettini
authors.forename: Ry
authors.initials: R
authors.lastname: Young
mesh_terms: D000595:Amino Acid Sequence; D017101:Bacteriophage P1 / Q000201:enzymology*; D001665:Binding Sites; D020134:Catalytic Domain; D002462:Cell Membrane / Q000201:enzymology; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D018360:Crystallography, X-Ray; D003545:Cysteine / Q000737:chemistry; D004789:Enzyme Activation; D004926:Escherichia coli / Q000201:enzymology / Q000821:virology; D007536:Isomerism; D008051:Lipid Bilayers; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009113:Muramidase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D011487:Protein Conformation; D021382:Protein Sorting Signals; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism
chemical_list: D008051:Lipid Bilayers; D021382:Protein Sorting Signals; D011993:Recombinant Fusion Proteins; D009113:Muramidase; D003545:Cysteine