Amino acid sequences of substrate-binding sites in chicken liver fatty acid synthase

1989

The complete amino acid sequence of chicken liver fatty acid synthase [acyl-CoA:malonyl-CoA C-acyltransferase (decarboxylating, oxoacyl-and enoyl-reducing, and thioester-hydrolyzing), EC 2.3.1.851 has been determined from the corresponding cDNA sequence. A 5.3-kilobase-pair (kbp) region of cDNA coding for chicken fatty acid synthase has been cloned and sequenced that is contiguous to the 2.3-kbp region previously sequenced [

Section: Resultsmentioning

confidence: 99%

“…This serine "loading" site is located in domain I of fatty acid synthase. The cysteine-containing "waiting" site peptide identified by iodoacetamide labeling (12) and located in domain I (13) indicates that the reading frame of the sequence is correct and that no omissions in nucleotides are present.…”

Section: Resultsmentioning

confidence: 99%

Molecular cloning and sequencing of chicken liver fatty acid synthase cDNA.

Holzer

Liu

1989

“…The thioesterase is located at the C terminus of the polypeptide and has considerable segmental flexibility (5). Amino acid sequences in active site regions of fatty acid synthase from chicken liver have been obtained (6).…”

mentioning

confidence: 99%

Molecular cloning and sequencing of DNA complementary to chicken liver fatty acid synthase mRNA.

Yuan

Liu

1988

The cDNA corresponding to 4.18 kilobases (kb) of the mRNA of chicken liver fatty acid synthase has been cloned and sequenced. The cDNA corresponds to the 3' end of the mRNA and consists of a 1.87-kb noncoding tail and a 2.31-kb region encoding 769 amino acids of the C terminus of the enzyme. The thioesterase at the C terminus, preceded by the acyl carrier protein, can be identified from known amino acid sequences. However, the identity of the enzymes N terminal to the acyl carrier protein could not be ascertained.The partial amino acid sequence of the chicken liver fatty acid synthase shows >70% similarity with the rat mammary gland enzyme.

“…The strong homologies between active site peptides from different species have suggested the hypothesis that the multifunctional polypeptides from animals and yeast have evolved from the monofunctional enzymes of lower species (2)(3)(4). In addition, a previous study (5) has suggested that the genes for the functional domains of the fatty acid synthase were originally separated, and these genes were connected to each other with different nucleotide sequences in various species.…”

Section: )mentioning

confidence: 99%

Homology analysis of the protein sequences of fatty acid synthases from chicken liver, rat mammary gland, and yeast.

Chang

1989

Homology analyses of the protein sequences of chicken liver and rat mammary gland fatty acid synthases [acyl-CoA:malonyl-CoA C-acyltransferase (decarboxylating, oxoacyl-and enoyl-reducing and thioester hydrolyzing), EC 2.3.1.85] and yeast fatty acid synthase [fatty-acyl-CoA synthase; acyl-CoA:malonyl-CoA C-acyltransferase (decarboxylating, oxoacyl-and enoyl-reducing), EC 2.3.1.86] were carried out. The amino acid sequences of the chicken and rat enzymes are 67% identical. If conservative substitutions are allowed, 78% of the amino acids are matched. A region of low homologies exists between the functional domains, in particular around amino acid residues 1059-1264 of the chicken enzyme. Homologies between the active sites of chicken and rat and of chicken and yeast enzymes have been analyzed by an alignment method. A high degree of homology exists between the active sites of the chicken and rat enzymes. However, the chicken and yeast enzymes show a lower degree of homology. The NADPHbinding dinucleotide folds of the fi-ketoacyl reductase and the enoyl reductase sites were identified by comparison with a known consensus sequence for the NADP-and FAD-binding dinucleotide folds. The active sites of all of the enzymes are primarily in hydrophobic regions of the protein. This study suggests that the genes for the functional domains of fatty acid synthase were originally separated, and these genes were connected to each other by using different connecting nucleotide sequences in different species. An alternative explanation for the differences in rat and chicken is a common ancestry and mutations in the joining regions during evolution. A higher mutation rate in the joining regions than in the active site regions of the enzymes without loss of function might be expected.Fatty acid synthase [acyl-CoA:malonyl-CoA C-acyltransferase (decarboxylating, oxoacyl-and enoyl-reducing and thioester hydrolyzing), EC 2.3.1.85] is a multienzyme complex that catalyzes the synthesis of palmitic acid from acetylCoA and malonyl-CoA, with NADPH as the reducing agent. Chicken and rat fatty acid synthases consist of two identical polypeptide chains and contain an acyl-carrier region and six different enzyme activities: 8-ketoacyl synthase, acetyl/ malonyl transacylase, dehydratase, enoyl and f-ketoacyl reductase, and thioesterase. Yeast fatty acid synthase [fattyacyl-CoA synthase; acyl-CoA:malonyl-CoA C-acyltransferase (decarboxylating, oxoacyl-and enoyl-reducing), EC 2.3.1.86] is a complex of two different polypeptide chains.One polypeptide contains an acyl-carrier region and two enzyme activities (f3-ketoacyl synthase and f3-ketoacyl reductase), and the other polypeptide contains the four remaining enzyme activities (enoyl reductase, acetyl transacylase, dehydratase, and malonyl/palmitoyl transacylase) (cf. ref. 1).The strong homologies between active site peptides from different species have suggested the hypothesis that the multifunctional polypeptides from animals and yeast have evolved from the monofunctional enzymes of lower...