title: Core structure of the outer membrane lipoprotein from Escherichia coli at 1.9 A resolution.
abstract: The outer membrane lipoprotein of the Escherichia coli cell envelope has characteristic lipid modifications at an amino-terminal cysteine and can exist in a form bound covalently to the peptidoglycan through a carboxyl-terminal lysine. The 56-residue polypeptide moiety of the lipoprotein, designated Lpp-56, folds into a stable, trimeric helical structure in aqueous solution. The 1.9 A resolution crystal structure of Lpp-56 comprises a parallel three-stranded coiled coil including a novel alanine-zipper unit and two helix-capping motifs. The amino-terminal motif forms a hydrogen-bonding network anchoring an umbrella-shaped fold. The carboxyl-terminal motif uses puckering of the tyrosine side-chains as a unique docking arrangement in helix termination. The structure provides an explanation for assembly and insertion of the lipoprotein molecules into the outer membrane of gram-negative bacteria and suggests a molecular target for antibacterial drug discovery.
authors.affiliation: Department of Biochemistry, Weill Medical College of Cornell University, New York, NY, 10021, USA.
authors.forename: W
authors.initials: W
authors.lastname: Shu
authors.forename: J
authors.initials: J
authors.lastname: Liu
authors.forename: H
authors.initials: H
authors.lastname: Ji
authors.forename: M
authors.initials: M
authors.lastname: Lu
mesh_terms: D000409:Alanine / Q000737:chemistry / Q000378:metabolism; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000737:chemistry*; D029968:Escherichia coli Proteins; D006860:Hydrogen Bonding; D008074:Lipoproteins; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D013329:Structure-Activity Relationship; D013816:Thermodynamics
chemical_list: D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D008074:Lipoproteins; C099932:Lpp protein, E coli; D010446:Peptide Fragments; D011994:Recombinant Proteins; D000409:Alanine