title: Structural basis of lipid binding for the membrane-embedded tetraacyldisaccharide-1-phosphate 4'-kinase LpxK.
abstract: The membrane-bound tetraacyldisaccharide-1-phosphate 4'-kinase, LpxK, catalyzes the sixth step of the lipid A (Raetz) biosynthetic pathway and is a viable antibiotic target against emerging Gram-negative pathogens. We report the crystal structure of lipid IVA, the LpxK product, bound to the enzyme, providing a rare glimpse into interfacial catalysis and the surface scanning strategy by which many poorly understood lipid modification enzymes operate. Unlike the few previously structurally characterized proteins that bind lipid A or its precursors, LpxK binds almost exclusively to the glucosamine/phosphate moieties of the lipid molecule. Steady-state kinetic analysis of multiple point mutants of the lipid-binding pocket pinpoints critical residues involved in substrate binding, and characterization of N-terminal helix truncation mutants uncovers the role of this substructure as a hydrophobic membrane anchor. These studies make critical contributions to the limited knowledge surrounding membrane-bound enzymes that act upon lipid substrates and provide a structural template for designing small molecule inhibitors targeting this essential kinase.
authors.affiliation: From the Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710 and.
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Emptage
authors.affiliation: From the Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710 and.
authors.forename: Nam K
authors.initials: NK
authors.lastname: Tonthat
authors.affiliation: the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37205.
authors.forename: John D
authors.initials: JD
authors.lastname: York
authors.affiliation: From the Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710 and.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Schumacher
authors.affiliation: From the Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710 and peizhou@biochem.duke.edu.
authors.forename: Pei
authors.initials: P
authors.lastname: Zhou
mesh_terms: D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D055785:Gene Knockdown Techniques; D005816:Genetic Complementation Test; D007700:Kinetics; D008055:Lipids / Q000737:chemistry*; D008565:Membrane Proteins / Q000378:metabolism*; D008958:Models, Molecular; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism*; D017354:Point Mutation; D011485:Protein Binding; D011487:Protein Conformation
chemical_list: D008055:Lipids; D008565:Membrane Proteins; D017853:Phosphotransferases (Alcohol Group Acceptor); C076042:tetraacyldisaccharide 4'-kinase
keywords: Antibiotic; Crystal Structure; Enzyme; Lipid A; Lipid Kinase; Lipid-binding Protein; Lipopolysaccharide (LPS); Membrane Protein