title: The solution structure of the active domain of CAP18--a lipopolysaccharide binding protein from rabbit leukocytes.
abstract: We have employed the circular dichroism (CD) technique to characterize the solution structure of CAP18(106-137), a lipopolysaccharide (LPS) binding, antimicrobial protein, and its interaction with lipid A. Our results revealed that CAP18(106-137) may exist in at least three lipid A concentration-dependent, primarily helix conformations. The 'model' structure of CAP18(106-137) in 30% (v/v) TFE, determined by nuclear magnetic resonance (NMR) technique, was found to be a complete and very rigid helix. In this conformation, the cationic and hydrophobic groups of CAP18(106-137) are separated into patches and stripes in such a way that it can favorably interact with lipid A through either coulombic interaction with the diphosphoryl groups or hydrophobic interaction with the fatty acyl chains.
authors.affiliation: Division of Structural Biology, Academia Sinica, Nankang, Taipei, Taiwan, ROC.
authors.forename: C
authors.initials: C
authors.lastname: Chen
authors.forename: R
authors.initials: R
authors.lastname: Brock
authors.forename: F
authors.initials: F
authors.lastname: Luh
authors.forename: P J
authors.initials: PJ
authors.lastname: Chou
authors.forename: J W
authors.initials: JW
authors.lastname: Larrick
authors.forename: R F
authors.initials: RF
authors.lastname: Huang
authors.forename: T H
authors.initials: TH
authors.lastname: Huang
mesh_terms: D000595:Amino Acid Sequence; D023181:Antimicrobial Cationic Peptides; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism*; D054804:Cathelicidins; D002942:Circular Dichroism; D008050:Lipid A; D008070:Lipopolysaccharides / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation
chemical_list: D023181:Antimicrobial Cationic Peptides; D002352:Carrier Proteins; D054804:Cathelicidins; D008050:Lipid A; D008070:Lipopolysaccharides; D010446:Peptide Fragments