title: Crystal structure of rat carnitine palmitoyltransferase II (CPT-II).
abstract: Carnitine palmitoyltransferase II (CPT-II) has a crucial role in the beta-oxidation of long-chain fatty acids in mitochondria. We report here the crystal structure of rat CPT-II at 1.9A resolution. The overall structure shares strong similarity to those of short- and medium-chain carnitine acyltransferases, although detailed structural differences in the active site region have a significant impact on the substrate selectivity of CPT-II. Three aliphatic chains, possibly from a detergent that is used for the crystallization, were found in the structure. Two of them are located in the carnitine and CoA binding sites, respectively. The third aliphatic chain may mimic the long-chain acyl group in the substrate of CPT-II. The binding site for this aliphatic chain does not exist in the short- and medium-chain carnitine acyltransferases, due to conformational differences among the enzymes. A unique insert in CPT-II is positioned on the surface of the enzyme, with a highly hydrophobic surface. It is likely that this surface patch mediates the association of CPT-II with the inner membrane of the mitochondria.
authors.affiliation: Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
authors.forename: Yu-Shan
authors.initials: YS
authors.lastname: Hsiao
authors.forename: Gerwald
authors.initials: G
authors.lastname: Jogl
authors.forename: Victoria
authors.initials: V
authors.lastname: Esser
authors.forename: Liang
authors.initials: L
authors.lastname: Tong
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002334:Carnitine O-Palmitoyltransferase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018360:Crystallography, X-Ray; D004194:Disease; D057927:Hydrophobic and Hydrophilic Interactions; D008928:Mitochondria / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D017434:Protein Structure, Tertiary; D051381:Rats; D016415:Sequence Alignment; D040681:Structural Homology, Protein
chemical_list: D002334:Carnitine O-Palmitoyltransferase