title: Structural basis for different specificities of acyltransferases associated with the human cytosolic and mitochondrial fatty acid synthases.
abstract: Animals employ two systems for the de novo biosynthesis of fatty acids: a megasynthase complex in the cytosol (type I) that produces mainly palmitate, and an ensemble of freestanding enzymes in the mitochondria (type II) that produces mainly octanoyl moieties. The acyltransferases responsible for initiation of fatty acid biosynthesis in the two compartments are distinguished by their different substrate specificities: the type I enzyme transfers both the acetyl primer and the malonyl chain extender, whereas the type II enzyme is responsible for translocation of only the malonyl substrate. Crystal structures for the type I and II enzymes, supported by in silico substrate docking studies and mutagenesis experiments that alter their respective specificities, reveal that, although the two enzymes adopt a similar overall fold, subtle differences at their catalytic centers account for their different specificities.
authors: Structural Genomics Consortium, University of Oxford, Oxford OX3 7LD, UK.
authors: Gabor
authors: G
authors: Bunkoczi
authors: Stephanie
authors: S
authors: Misquitta
authors: Xiaoqiu
authors: X
authors: Wu
authors: Wen Hwa
authors: WH
authors: Lee
authors: Alexandra
authors: A
authors: Rojkova
authors: Grazyna
authors: G
authors: Kochan
authors: Kathryn L
authors: KL
authors: Kavanagh
authors: Udo
authors: U
authors: Oppermann
authors: Stuart
authors: S
authors: Smith
mesh_terms: D000217:Acyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D020134:Catalytic Domain; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D003600:Cytosol / Q000201:enzymology; D054890:Fatty Acid Synthase, Type I / Q000737:chemistry* / Q000378:metabolism; D054889:Fatty Acid Synthase, Type II / Q000737:chemistry* / Q000378:metabolism; D005227:Fatty Acids / Q000096:biosynthesis; D006801:Humans; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: D005227:Fatty Acids; D050505:Mutant Proteins; D000217:Acyltransferases; D054890:Fatty Acid Synthase, Type I; D054889:Fatty Acid Synthase, Type II