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Winkler U, Säftel W, Stabenau H. A new type of a multifunctional beta-oxidation enzyme in euglena. Plant Physiol 2003; 131:753-62. [PMID: 12586899 PMCID: PMC166851 DOI: 10.1104/pp.013151] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2002] [Revised: 10/01/2002] [Accepted: 10/28/2002] [Indexed: 05/23/2023]
Abstract
The biochemical and molecular properties of the beta-oxidation enzymes from algae have not been investigated yet. The present study provides such data for the phylogenetically old alga Euglena (Euglena gracilis). A novel multifunctional beta-oxidation complex was purified to homogeneity by ammonium sulfate precipitation, density gradient centrifugation, and ion-exchange chromatography. Monospecific antibodies used in immunocytochemical experiments revealed that the enzyme is located in mitochondria. The enzyme complex is composed of 3-hydroxyacyl-coenzyme A (-CoA) dehydrogenase, 2-enoyl-CoA hydratase, thiolase, and epimerase activities. The purified enzyme exhibits a native molecular mass of about 460 kD, consisting of 45.5-, 44.5-, 34-, and 32-kD subunits. Subunits dissociated from the complete complex revealed that the hydratase and the thiolase functions are located on the large subunits, whereas two dehydrogenase functions are located on the two smaller subunits. Epimerase activity was only measurable in the complete enzyme complex. From the use of stereoisomers and sequence data, it was concluded that the 2-enoyl-CoA hydratase catalyzes the formation of L-hydroxyacyl CoA isomers and that both of the different 3-hydroxyacyl-CoA dehydrogenase functions on the 32- and 34-kD subunits are specific to L-isomers as substrates, respectively. All of these data suggest that the Euglena enzyme belongs to the family of beta-oxidation enzymes that degrade acyl-CoAs via L-isomers and that it is composed of subunits comparable with subunits of monofunctional beta-oxidation enzymes. It is concluded that the Euglena enzyme phylogenetically developed from monospecific enzymes in archeons by non-covalent combination of subunits and presents an additional line for the evolutionary development of multifunctional beta-oxidation enzymes.
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Affiliation(s)
- Uwe Winkler
- Department of Biology, University of Oldenburg, P.O. Box 2503, D-26111 Oldenburg, Germany.
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102
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Tsuge T, Taguchi K, Seiichi T, Doi Y. Molecular characterization and properties of (R)-specific enoyl-CoA hydratases from Pseudomonas aeruginosa: metabolic tools for synthesis of polyhydroxyalkanoates via fatty acid beta-oxidation. Int J Biol Macromol 2003; 31:195-205. [PMID: 12568928 DOI: 10.1016/s0141-8130(02)00082-x] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The use of (R)-specific enoyl-coenzyme A (CoA) hydratase (PhaJ) provides a powerful tool for polyhydroxyalkanoate (PHA) synthesis from fatty acids or plant oils in recombinant bacteria. PhaJ provides monomer units for PHA synthesis from the fatty acid ss-oxidation cycle. Previously, two phaJ genes (phaJ1(Pa) and phaJ2(Pa)) were identified in Pseudomonas aeruginosa. This report identifies two new phaJ genes (phaJ3(Pa) and phaJ4(Pa)) in P. aeruginosa through a genomic database search. The abilities of the four PhaJ(Pa) proteins and the (R)-3-hydroxyacyl-acyl carrier protein [(R)-3HA-ACP] dehydrases, FabA(Pa) and FabZ(Pa), to supply monomers from enoyl-CoA substrates for PHA synthesis were determined. The presence of either PhaJ1(Pa) or PhaJ4(Pa) in recombinant Escherichia coli led to the high levels of PHA accumulation (as high as 36-41 wt.% in dry cells) consisting of mainly short- (C4-C6) and medium-chain-length (C6-C10) 3HA units, respectively. Furthermore, detailed characterizations of PhaJ1(Pa) and PhaJ4(Pa) were performed using purified samples. Kinetic analysis revealed that only PhaJ4(Pa) exhibits almost constant maximum reaction rates (V(max)) irrespective of the chain length of the substrates. The assay for stereospecific hydration revealed that, unlike PhaJ1(Pa), PhaJ4(Pa) has relatively low (R)-specificity. These hydratases may be very useful as monomer-suppliers for the synthesis of designed PHAs in recombinant bacteria.
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Affiliation(s)
- Takeharu Tsuge
- Department of Innovative and Engineered Materials, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan.
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103
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Hisano T, Tsuge T, Fukui T, Iwata T, Miki K, Doi Y. Crystal structure of the (R)-specific enoyl-CoA hydratase from Aeromonas caviae involved in polyhydroxyalkanoate biosynthesis. J Biol Chem 2003; 278:617-24. [PMID: 12409309 DOI: 10.1074/jbc.m205484200] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The (R)-specific enoyl coenzyme A hydratase ((R)-hydratase) from Aeromonas caviae catalyzes the addition of a water molecule to trans-2-enoyl coenzyme A (CoA), with a chain-length of 4-6 carbons, to produce the corresponding (R)-3-hydroxyacyl-CoA. It forms a dimer of identical subunits with a molecular weight of about 14,000 and is involved in polyhydroxyalkanoate (PHA) biosynthesis. The crystal structure of the enzyme has been determined at 1.5-A resolution. The structure of the monomer consists of a five-stranded antiparallel beta-sheet and a central alpha-helix, folded into a so-called "hot dog" fold, with an overhanging segment. This overhang contains the conserved residues including the hydratase 2 motif residues. In dimeric form, two beta-sheets are associated to form an extended 10-stranded beta-sheet, and the overhangs obscure the putative active sites at the subunit interface. The active site is located deep within the substrate-binding tunnel, where Asp(31) and His(36) form a catalytic dyad. These residues are catalytically important as confirmed by site-directed mutagenesis and are possibly responsible for the activation of a water molecule and the protonation of a substrate molecule, respectively. Residues such as Leu(65) and Val(130) are situated at the bottom of the substrate-binding tunnel, defining the preference of the enzyme for the chain length of the substrate. These results provide target residues for protein engineering, which will enhance the significance of this enzyme in the production of novel PHA polymers. In addition, this study provides the first structural information of the (R)-hydratase family and may facilitate further functional studies for members of the family.
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Affiliation(s)
- Tamao Hisano
- RIKEN Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
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104
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Abstract
Enoyl-CoA hydratase (ECH) catalyzes the second step in the physiologically important beta-oxidation pathway of fatty acid metabolism. This enzyme facilitates the syn-addition of a water molecule across the double bond of a trans-2-enoyl-CoA thioester, resulting in the formation of a beta-hydroxyacyl-CoA thioester. The catalytic mechanism of this proficient enzyme has been studied in great depth through a combination of kinetic, spectroscopic, and structural techniques, and is proposed to occur via the formation of a single transition state. Sequence alignment and mutagenesis studies have implicated the key residues important for catalysis: Gly-141, Glu-144, and Glu-164 (rat liver ECH numbering). The two catalytic glutamic acid residues are believed to act in concert to activate a water molecule, while Gly-141 is proposed to be involved in substrate activation. Recently, two potent inhibitors of ECH have been reported in the literature, which result in the irreversible inactivation of the enzyme via covalent adduct formation. This review summarizes studies on the structure, mechanism, and inhibition of ECH.
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Affiliation(s)
- Gautam Agnihotri
- Division of Medicinal Chemistry, College of Pharmacy, and Department of Chemistry and Biochemistry, University of Texas, Austin 78712, USA
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105
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Meyer K, Jia Y, Cao WQ, Kashireddy P, Rao MS. Expression of peroxisome proliferator-activated receptor alpha, and PPARalpha regulated genes in spontaneously developed hepatocellular carcinomas in fatty acyl-CoA oxidase null mice. Int J Oncol 2002; 21:1175-80. [PMID: 12429965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023] Open
Abstract
Fatty acyl-CoA oxidase null mice (AOX-/-) develop hepatocellular carcinomas in 100% of animals between 10 and 15 months. We evaluated spontaneously developed HCC in AOX-/- mice for PPARalpha, PPARalpha regulated genes and peroxisome volume density and compared with adjacent non-neoplastic liver and liver in wild-type (AOX+/+) and heterozygous (AOX+/-) mice. The level of PPARalpha mRNA was 2.5-fold higher in HCC compared to the adjacent liver. mRNAs of PPARalpha regulated genes such as peroxisomal bifunctional enzyme, thiolase, cytochrome P450 CYP4A1 and CYP4A3 were similar in HCC and adjacent liver and increased by 7- to 22-fold compared with wild-type and heterozygous mice. Immunoblot analysis of HCC showed high amounts of PPARalpha, peroxisomal bifunctional enzyme and thiolase. Electron microscopic examination revealed 3.8 and 8.3-fold increase in the volume density of peroxisomes in HCC and adjacent liver, respectively, compared to the volume density in wild-type mice. These results demonstrate that spontaneously developed HCC in AOX-/- mice display a similar type of pleiotropic responses to high levels of PPARalpha ligands as the non-neoplastic liver. The changes observed in HCC and adjacent liver in AOX-/- mice were identical to those observed in rats and mice exposed to peroxisome proliferators.
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Affiliation(s)
- Kirstin Meyer
- Department of Pathology, The Feinberg School of Medicine, Chicago, IL 60611-3008, USA
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106
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Abstract
Recent advances in the structural biology of the enzymes involved in fatty acid oxidation have revealed their catalytic mechanisms and modes of substrate binding. Although these enzymes all use coenzyme A (CoA) thioesters as substrates, they share no common polypeptide folding topology or CoA-binding motif. Each family adopts an entirely unique protein fold. Their mode of binding the CoA thioester is similar in that the fatty-acyl moiety is buried inside the protein and the nucleotide portion is mainly exposed to solvent; however, the conformations of the enzyme-bound CoA ligands vary considerably. Furthermore, a comparison of these structures suggests a structural basis for the broad substrate chain length specificity that is a unique feature of these enzymes.
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Affiliation(s)
- Jung-Ja P Kim
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee 53226, USA.
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107
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Klose DA, Kölker S, Heinrich B, Prietsch V, Mayatepek E, von Kries R, Hoffmann GF. Incidence and short-term outcome of children with symptomatic presentation of organic acid and fatty acid oxidation disorders in Germany. Pediatrics 2002; 110:1204-11. [PMID: 12456920 DOI: 10.1542/peds.110.6.1204] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE To determine the incidence of symptomatic children with inherited organic acid disorders (OADs) and fatty acid oxidation disorders (FAODs) in Germany. METHODS An active surveillance of symptomatic children with inherited OADs and FAODs was conducted during a time period of 24 months (1999-2000) in Germany. Monthly inquiries were sent to all Departments of Pediatrics by the German Pediatric Surveillance Unit (ESPED) and quarterly to all specialized metabolic laboratories. Newly diagnosed patients were added to the database, recording clinical and biochemical information via a standardized questionnaire. RESULTS Prospective surveillance enrolling 844 575 children identified a total of 57 symptomatic children with newly diagnosed OADs or FAODs in states with conventional neonatal screening, resulting in an estimated cumulative incidence of 1:14 800. The most frequent diagnosis among these children was medium-chain acyl-CoA dehydrogenase deficiency (n = 20). The majority of symptomatic children revealed clinical symptoms during the first year of life (n = 36), frequently presenting with acute metabolic crises (n = 31). Eight children died during these crises. Notably, 47 of the symptomatic children suffered from diseases potentially detectable by expanded neonatal screening programs. This subgroup included 29 children presenting with metabolic crises and 7 of the 8 deaths. CONCLUSIONS Despite increased clinical awareness of OADs and FAODs, the mortality and morbidity for these children remains high, if they are diagnosed after manifestation of clinical disease. An introduction of nationwide neonatal screening programs would change the focus for organic acid analysis from patients presenting with acute metabolic crises to more chronic clinical presentations, especially the cerebral organic acid disorders.
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Affiliation(s)
- Daniela A Klose
- Division of Metabolic and Endocrine Disorders, University Children's Hospital, Heidelberg, Germany
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108
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Sabbah HN, Chandler MP, Mishima T, Suzuki G, Chaudhry P, Nass O, Biesiadecki BJ, Blackburn B, Wolff A, Stanley WC. Ranolazine, a partial fatty acid oxidation (pFOX) inhibitor, improves left ventricular function in dogs with chronic heart failure. J Card Fail 2002; 8:416-22. [PMID: 12528095 DOI: 10.1054/jcaf.2002.129232] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND Abnormalities of energy metabolism are often cited as key elements in the progressive worsening of left ventricular (LV) dysfunction that characterizes the heart failure (HF) state. The present study tested the hypothesis that partial inhibition of fatty acids will ameliorate the hemodynamic abnormalities associated with HF. METHODS AND RESULTS Chronic HF (LV ejection fraction 27 +/- 1%) was produced in 13 dogs by intracoronary microembolizations. Hemodynamic and angiographic measurements were made before and 40 minutes after intravenous administration of ranolazine, a partial fatty acid oxidation (pFOX) inhibitor. Ranolazine was administered as an intravenous bolus dose of 0.5 mg/kg followed by a continuous infusion for 40 minutes at a constant rate of 1.0 mg / kg / hr. Ranolazine significantly increased LV ejection fraction (27 +/- 1 versus 36 +/- 2, P =.0001), peak LV +dP/dt (1712 +/- 122 versus 1900 +/- 112 mm Hg/sec, P =.001), and stroke volume (20 +/- 1 versus 26 +/- 1 mL). These improvements occurred in the absence of any effects on heart rate or systemic pressure. In 8 normal healthy dogs, ranolazine had no effect on LV ejection fraction or any other index of LV function. CONCLUSIONS In dogs with HF, acute intravenous administration of the pFOX inhibitor ranolazine improves LV systolic function. The absence of any hemodynamic effects of ranolazine in normal dogs suggests that the drug is devoid of any positive inotropic effects and acts primarily by optimizing cardiac metabolism in the setting of chronic HF.
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Affiliation(s)
- Hani N Sabbah
- Department of Medicine, Division of Cardiovascular Medicine, Henry Ford Heart and Vascular Institute, Detroit, Michigan 48202, USA
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109
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IJlst L, Loupatty FJ, Ruiter JPN, Duran M, Lehnert W, Wanders RJA. 3-Methylglutaconic aciduria type I is caused by mutations in AUH. Am J Hum Genet 2002; 71:1463-6. [PMID: 12434311 PMCID: PMC378594 DOI: 10.1086/344712] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2002] [Accepted: 09/11/2002] [Indexed: 11/03/2022] Open
Abstract
3-Methylglutaconic aciduria type I is an autosomal recessive disorder clinically characterized by various symptoms ranging from delayed speech development to severe neurological handicap. This disorder is caused by a deficiency of 3-methylglutaconyl-CoA hydratase, one of the key enzymes of leucine degradation. This results in elevated urinary levels of 3-methylglutaconic acid, 3-methylglutaric acid, and 3-hydroxyisovaleric acid. By heterologous expression in Escherichia coli, we show that 3-methylglutaconyl-CoA hydratase is encoded by the AUH gene, whose product had been reported elsewhere as an AU-specific RNA-binding protein. Mutation analysis of AUH in two patients revealed a nonsense mutation (R197X) and a splice-site mutation (IVS8-1G-->A), demonstrating that mutations in AUH cause 3-methylglutaconic aciduria type I.
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Affiliation(s)
- Lodewijk IJlst
- Departments of Clinical Chemistry and Pediatrics, Emma Children’s Hospital, Academic Medical Center, University of Amsterdam, Amsterdam; and University Children’s Hospital, Freiburg, Germany
| | - Ference J. Loupatty
- Departments of Clinical Chemistry and Pediatrics, Emma Children’s Hospital, Academic Medical Center, University of Amsterdam, Amsterdam; and University Children’s Hospital, Freiburg, Germany
| | - Jos P. N. Ruiter
- Departments of Clinical Chemistry and Pediatrics, Emma Children’s Hospital, Academic Medical Center, University of Amsterdam, Amsterdam; and University Children’s Hospital, Freiburg, Germany
| | - Marinus Duran
- Departments of Clinical Chemistry and Pediatrics, Emma Children’s Hospital, Academic Medical Center, University of Amsterdam, Amsterdam; and University Children’s Hospital, Freiburg, Germany
| | - Willy Lehnert
- Departments of Clinical Chemistry and Pediatrics, Emma Children’s Hospital, Academic Medical Center, University of Amsterdam, Amsterdam; and University Children’s Hospital, Freiburg, Germany
| | - Ronald J. A. Wanders
- Departments of Clinical Chemistry and Pediatrics, Emma Children’s Hospital, Academic Medical Center, University of Amsterdam, Amsterdam; and University Children’s Hospital, Freiburg, Germany
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110
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Abstract
Standardization of the nutritional care for patients with fatty-acid oxidation disorders is lacking. A literature review and national survey of metabolic dietitians describes the range of therapeutic strategies currently employed in the U.S. to treat patients with fatty-acid oxidation disorders. Questionnaire responses provided by dietitians specializing in metabolic disorders evaluated practices used for treatment of fatty acid oxidation disorders, medium-chain acyl-CoA dehydrogenase deficiency (MCAD), very-long-chain acyl-CoA dehydrogenase deficiency (VLCAD), long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHAD), long-chain acyl-CoA dehydrogenase deficiency (LCAD), and Trifunctional Protein deficiency (TFP). This survey reveals a significant lack of evidence supporting the protocols in use. Recent advances in tandem mass spectrometry technology promises an increase in the number of identified patients with fatty-acid oxidation disorders, which reinforces the need for comprehensive, clinical research studies to determine optimal care for patients with these genetic disorders.
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111
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Bell AF, Feng Y, Hofstein HA, Parikh S, Wu J, Rudolph MJ, Kisker C, Whitty A, Tonge PJ. Stereoselectivity of enoyl-CoA hydratase results from preferential activation of one of two bound substrate conformers. Chem Biol 2002; 9:1247-55. [PMID: 12445775 DOI: 10.1016/s1074-5521(02)00263-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Enoyl-CoA hydratase catalyzes the hydration of trans-2-crotonyl-CoA to 3(S)- and 3(R)-hydroxybutyryl-CoA with a stereoselectivity (3(S)/3(R)) of 400,000 to 1. Importantly, Raman spectroscopy reveals that both the s-cis and s-trans conformers of the substrate analog hexadienoyl-CoA are bound to the enzyme, but that only the s-cis conformer is polarized. This selective polarization is an example of ground state strain, indicating the existence of catalytically relevant ground state destabilization arising from the selective complementarity of the enzyme toward the transition state rather than the ground state. Consequently, the stereoselectivity of the enzyme-catalyzed reaction results from the selective activation of one of two bound substrate conformers rather than from selective binding of a single conformer. These findings have important implications for inhibitor design and the role of ground state interactions in enzyme catalysis.
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Affiliation(s)
- Alasdair F Bell
- Department of Chemistry, Center for Structural Biology, SUNY at Stony Brook, Stony Brook, NY 11794, USA
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112
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Abstract
In female rats, ovariectomy (OVX) is associated with increased body fat and insulin resistance, and estradiol replacement prevents these alterations. These metabolic changes related to the estrogen-deficient state might be due, in part, to alterations in skeletal muscle substrate metabolism. We tested the hypothesis that estradiol affects the regulation of enzymes involved in substrate oxidation and storage within skeletal muscle. Specifically, we examined enzymes involved in the regulation of glycogen synthesis (glycogen synthase [GS]), glycolysis (phosphofructokinase [PFK]), tricarboxylic acid cycle activity (citrate synthase [CS]), and beta-oxidation (beta-hydroxyacyl-CoA dehydrogenase [beta-HADH]). Twenty-two, female Sprague-Dawley rats (7 to 8 weeks old) were separated into 3 groups: OVX + placebo (P; n = 8), OVX + estradiol (E(2); n = 8), and sham-operated (S; n = 6). Rats from E(2) and P groups were pair-fed to the S group to control for OVX-induced changes in food intake. After 16 days, activities of GS, PFK, CS, and beta-HADH were measured in vastus medialis muscle. GS fractional velocity was significantly lower (P <.05) in P (mean +/- SE; 39.7% +/- 6.2%) compared with both S (61.9% +/- 8.8%) and E(2) (65.8% +/- 8.4%) rats. In addition, E(2) rats (41.4 +/- 2.0) had significantly higher (P <.05) CS activity than P (34.9 +/- 2.0) and S (33.9 +/- 1.4 micromol/min/g) groups. There was no effect of OVX or estradiol replacement on beta-HADH or PFK. Our results suggest that, independent of alterations in food intake, estradiol availability affects the regulation of enzymes involved in nonoxidative glucose disposal (GS) and oxidative metabolism (CS) in skeletal muscle.
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Affiliation(s)
- Travis Beckett
- Department of Medicine, University of Vermont, Burlington, VT 05405, USA
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113
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Kiema TR, Taskinen JP, Pirilä PL, Koivuranta KT, Wierenga RK, Hiltunen JK. Organization of the multifunctional enzyme type 1: interaction between N- and C-terminal domains is required for the hydratase-1/isomerase activity. Biochem J 2002; 367:433-41. [PMID: 12106015 PMCID: PMC1222896 DOI: 10.1042/bj20020292] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2002] [Revised: 06/18/2002] [Accepted: 07/10/2002] [Indexed: 11/17/2022]
Abstract
Rat peroxisomal multifunctional enzyme type 1 (perMFE-1) is a monomeric protein of beta-oxidation. We have defined five functional domains (A, B, C, D and E) in the perMFE-1 based on comparison of the amino acid sequence with homologous proteins from databases and structural data of the hydratase-1/isomerases (H1/I) and (3 S )-hydroxyacyl-CoA dehydrogenases (HAD). Domain A (residues 1-190) comprises the H1/I fold and catalyses both 2-enoyl-CoA hydratase-1 and Delta(3)-Delta(2)-enoyl-CoA isomerase reactions. Domain B (residues 191-280) links domain A to the (3 S )-dehydrogenase region, which includes both domain C (residues 281-474) and domain D (residues 480-583). Domains C and D carry features of the dinucleotide-binding and the dimerization domains of monofunctional HADs respectively. Domain E (residues 584-722) has sequence similarity to domain D of the perMFE-1, which suggests that it has evolved via partial gene duplication. Experiments with engineered perMFE-1 variants demonstrate that the H1/I competence of domain A requires stabilizing interactions with domains D and E. The variant His-perMFE (residues 288-479)Delta, in which the domain C is deleted, is stable and has hydratase-1 activity. It is proposed that the extreme C-terminal domain E in perMFE-1 serves the following three functions: (i) participation in the folding of the N-terminus into a functionally competent H1/I fold, (ii) stabilization of the dehydrogenation domains by interaction with the domain D and (iii) the targeting of the perMFE-1 to peroxisomes via its C-terminal tripeptide.
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Affiliation(s)
- Tiila-Riikka Kiema
- Biocenter Oulu and Department of Biochemistry, University of Oulu, P.O. Box 3000, FIN-90014, Finland
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114
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Lensink MF, Haapalainen AM, Hiltunen JK, Glumoff T, Juffer AH. Response of SCP-2L domain of human MFE-2 to ligand removal: binding site closure and burial of peroxisomal targeting signal. J Mol Biol 2002; 323:99-113. [PMID: 12368102 DOI: 10.1016/s0022-2836(02)00939-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In the study of the structure and function relationship of human MFE-2, we have investigated the dynamics of human MFE-2SCP-2L (hSCP-2L) and its response to ligand removal. A comparison was made with homologous rabbit SCP-2. Breathing and a closing motion are found, identifiable with an adjustment in size and a closing off of the binding pocket. Crucial residues for structural integrity have been identified. Particularly mobile areas of the protein are loop 1 that is connecting helices A and C in space, and helix D, next to the entrance of the pocket. In hSCP-2L, the binding pocket gets occupied by Phe93, which is making a tight hydrophobic contact with Trp36. In addition, it is found that the C-terminal peroxisomal targeting signal (PTS1) that is solvent exposed in the complexed structure becomes buried when no ligand is present. Moreover, an anti-correlation exists between burial of PTS1 and the size of the binding pocket. The results are in accordance with plant nsLTPs, where a similar accommodation of binding pocket size was found after ligand binding/removal. Furthermore, the calculations support the suggestion of a ligand-assisted targeting mechanism.
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Affiliation(s)
- M F Lensink
- Biocenter Oulu and Department of Biochemistry, University of Oulu, P.O. Box 3000, FIN-90014, Oulu, Finland
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115
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Fiedler S, Steinbüchel A, Rehm BHA. The role of the fatty acid beta-oxidation multienzyme complex from Pseudomonas oleovorans in polyhydroxyalkanoate biosynthesis: molecular characterization of the fadBA operon from P. oleovorans and of the enoyl-CoA hydratase genes phaJ from P. oleovorans and Pseudomonas putida. Arch Microbiol 2002; 178:149-60. [PMID: 12115060 DOI: 10.1007/s00203-002-0444-0] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2002] [Revised: 05/13/2002] [Accepted: 05/14/2002] [Indexed: 10/27/2022]
Abstract
In order to investigate the role of the putative epimerase function of the beta-oxidation multienzyme complex (FadBA) in the provision of (R)-3-hydroxyacyl-CoA thioesters for medium-chain-length polyhydroxyalkanoate (PHA(MCL)) biosynthesis, the fadBA(Po) operon of Pseudomonas oleovorans was cloned and characterized. The fadBA(Po) operon and a class-II PHA synthase gene of Pseudomonas aeruginosa were heterologously co-expressed in Escherichia coli to determine whether the putative epimerase function of FadBA(Po) has the ability to provide precursors for PHA accumulation in a non-PHA-accumulating bacterium. Cultivation studies with fatty acids as carbon source revealed that FadBA(Po) did not mediate PHA(MCL) biosynthesis in the E. coli wild-type strain harboring a PHA synthase gene. However, PHA accumulation was strongly impaired in a recombinant E. coli fadB mutant, which harbored a PHA synthase gene. These data indicate that in pseudomonads FadBA does not possess the inherent property, based on a putative epimerase function, to provide the ( R)-enantiomer of 3-hydroxyacyl-CoA efficiently and that other linking enzymes are required to efficiently channel intermediates of beta-oxidation towards PHA(MCL) biosynthesis. However, the phaJ gene from P. oleovorans and from Pseudomonas putida, both of which encoded a 3- Re enoyl-CoA hydratase, was identified. The co-expression of phaJ(Po/Pp) with either a class-II PHA synthase gene or the PHA synthase gene from Aeromonas punctata in E. coli revealed that PhaJ(Po/Pp) mediated biosynthesis of either PHA(MCL), contributing to about 1% of cellular dry mass, or of poly(3-hydroxybutyrate- co-3-hydroxyhexanoate), contributing to 3.6% of cellular dry mass, when grown on decanoate. These data indicate that FadBA(Po)does not mediate the provision of (R)-3-hydroxyacyl-CoA, which resembles FadBA of non-PHA-accumulating bacteria, and that 3- Re enoyl-CoA hydratases are required to divert intermediates of fatty acid beta-oxidation towards PHA biosynthesis in P. oleovorans.
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Affiliation(s)
- Silke Fiedler
- Institut für Mikrobiologie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 3, 48149 Münster, Germany
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116
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Mitra A, Mayer MJ, Mellon FA, Michael AJ, Narbad A, Parr AJ, Waldron KW, Walton NJ. 4-Hydroxycinnamoyl-CoA hydratase/lyase, an enzyme of phenylpropanoid cleavage from Pseudomonas, causes formation of C(6)-C(1) acid and alcohol glucose conjugates when expressed in hairy roots of Datura stramonium L. Planta 2002; 215:79-89. [PMID: 12012244 DOI: 10.1007/s00425-001-0712-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2001] [Accepted: 09/30/2001] [Indexed: 05/18/2023]
Abstract
4-Hydroxycinnamoyl-CoA hydratase/lyase (HCHL), a crotonase homologue of phenylpropanoid catabolism from Pseudomonas fluorescens strain AN103, led to the formation of 4-hydroxybenzaldehyde metabolites when expressed in hairy root cultures of Datura stramonium L. established by transformation with Agrobacterium rhizogenes. The principal new compounds observed were the glucoside and glucose ester of 4-hydroxybenzoic acid, together with 4-hydroxybenzyl alcohol- O-beta- D-glucoside. In lines actively expressing HCHL, these together amounted to around 0.5% of tissue fresh mass. No protocatechuic derivatives were found, although a trace of vanillic acid-beta- D-glucoside was detected. There was no accumulation of 4-hydroxybenzaldehydes, whether free or in the form of their glucose conjugates. There was some evidence suggesting a diminished availability of feruloyl-CoA for the production of feruloyl putrescine and coniferyl alcohol. The findings are discussed in the context of a diversion of phenylpropanoid metabolism, and the ability of plants and plant cultures to conjugate phenolic compounds.
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Affiliation(s)
- Adinpunya Mitra
- Food Safety Science Division, Institute of Food Research, Norwich Resesrch Park, Colney, Norwich NR4 7UA, UK
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117
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Fukui T, Abe H, Doi Y. Engineering of Ralstonia eutropha for production of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) from fructose and solid-state properties of the copolymer. Biomacromolecules 2002; 3:618-24. [PMID: 12005535 DOI: 10.1021/bm0255084] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recombinant Ralstonia eutropha capable of producing poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer [P(3HB-co-3HHx)] from fructose was engineered by introduction of genes for crotonyl-CoA reductase (CCR) from Streptomyces cinnamonensis (ccrSc) and for PHA synthase and (R)-specific enoyl-CoA hydratase from Aeromonas caviae (phaC-JAc). In this recombinant strain, C6-acyl-CoA intermediates were provided via beta-ketothiolase-mediated elongation of butyryl-CoA, which was generated from crotonyl-CoA by the function of CCR. The recombinant strain could accumulate the copolyester up to 48 wt % of dry cell weight with 1.5 mol % of 3HHx fraction from fructose, when the expression of ccrSc under the control of the PBAD promoter was induced with 0.01% L-arabinose. The absence of L-arabinose or the deletion of ccrSc from the plasmid resulted in accumulation of poly(3-hydroxybutyrate) homopolymer, indicating the critical role of CCR in the formation of the 3-hydroxyhexanoate unit. Higher CCR activity obtained by the addition of a larger amount of L-arabinose did not affect the composition but reduced the intracellular content of the copolyester. The P(3HB-co-1.5 mol % 3HHx) copolyester produced from fructose by the recombinant R. eutropha showed relatively lower melting temperatures (150 degrees C and 161 degrees C) and lower crystallinity (48 +/- 5%) compared to those (175 degrees C and 60 +/- 5%) of P(3HB) homopolymer. It has been found that the incorporation of a small amount (1.5 mol %) of 3HHx units into P(3HB) sequences leads to a remarkable change in the solid-state properties of P(3HB) crystals. The present study demonstrates the potential of the engineered pathway for the production of copolyesters having favorable characteristics from inexpensive carbon resources.
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Affiliation(s)
- Toshiaki Fukui
- Polymer Chemistry Laboratory, RIKEN Institute, Hirosawa 2-1, Wako-shi, Saitama 351-0198, Japan
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118
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Abstract
According to current views, the second peroxisomal beta-oxidation pathway is responsible for the degradation of the side chain of bile acid intermediates. Peroxisomal multifunctional enzyme type 2 [peroxisomal multifunctional 2-enoyl-CoA hydratase/(R)-3-hydroxyacyl-CoA dehydrogenase; MFE-2] catalyses the second (hydration) and third (dehydrogenation) reactions of the pathway. Deficiency of MFE-2 leads to accumulation of very-long-chain fatty acids, 2-methyl-branched fatty acids and C(27) bile acid intermediates in plasma, but bile acid synthesis is not blocked completely. In this study we describe an alternative pathway, which allows MFE-2 deficiency to be overcome. The alternative pathway consists of alpha-methylacyl-CoA racemase and peroxisomal multifunctional enzyme type 1 [peroxisomal multifunctional 2-enoyl-CoA hydratase/(S)-3-hydroxyacyl-CoA dehydrogenase; MFE-1]. (24E)-3alpha,7alpha,12alpha-Trihydroxy-5beta-cholest-24-enoyl-CoA, the presumed physiological isomer, is hydrated by MFE-1 with the formation of (24S,25S)-3alpha,7alpha,12alpha,24-tetrahydroxy-5beta-cholestanoyl-CoA [(24S,25S)-24-OH-THCA-CoA], which after conversion by a alpha-methylacyl-CoA racemase into the (24S,25R) isomer can again be dehydrogenated by MFE-1 to 24-keto-3alpha,7alpha,12alpha-trihydroxycholestanoyl-CoA, a physiological intermediate in cholic acid synthesis. The discovery of the alternative pathway of cholesterol side-chain oxidation will improve diagnosis of peroxisomal deficiencies by identification of serum 24-OH-THCA-CoA diastereomer profiles.
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Affiliation(s)
- Dean A Cuebas
- Department of Chemistry, Southwest Missouri State University, Springfield, MO 65804, USA
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119
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Alipui OD, Zhang D, Schulz H. Direct hydration of 3-octynoyl-CoA by crotonase: a missing link in Konrad Bloch's enzymatic studies with 3-alkynoyl thioesters. Biochem Biophys Res Commun 2002; 292:1171-4. [PMID: 11969208 DOI: 10.1006/bbrc.2001.2024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Olivier D Alipui
- Department of Chemistry, City College, the Graduate School of the City University of New York, Convent Avenue at 138th Street, New York, NY 10031, USA
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120
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Abstract
The protein sequence and structure databases are now sufficiently representative that strategies nature uses to evolve new catalytic functions can be identified. Groups of divergently related enzymes whose members catalyze different reactions but share a common partial reaction, intermediate, or transition state (mechanistically diverse superfamilies) have been discovered, including the enolase, amidohydrolase, thiyl radical, crotonase, vicinal-oxygen-chelate, and Fe-dependent oxidase superfamilies. Other groups of divergently related enzymes whose members catalyze different overall reactions that do not share a common mechanistic strategy (functionally distinct suprafamilies) have also been identified: (a) functionally distinct suprafamilies whose members catalyze successive transformations in the tryptophan and histidine biosynthetic pathways and (b) functionally distinct suprafamilies whose members catalyze different reactions in different metabolic pathways. An understanding of the structural bases for the catalytic diversity observed in super- and suprafamilies may provide the basis for discovering the functions of proteins and enzymes in new genomes as well as provide guidance for in vitro evolution/engineering of new enzymes.
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Affiliation(s)
- J A Gerlt
- Departments of Biochemistry and Chemistry, University of Illinois, Urbana, Illinois 61801, USA.
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121
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Abstract
Most serine cycle methylotrophic bacteria lack isocitrate lyase and convert acetyl coenzyme A (acetyl-CoA) to glyoxylate via a novel pathway thought to involve butyryl-CoA and propionyl-CoA as intermediates. In this study we have used a genome analysis approach followed by mutation to test a number of genes for involvement in this novel pathway. We show that methylmalonyl-CoA mutase, an R-specific crotonase, isobutyryl-CoA dehydrogenase, and a GTPase are involved in glyoxylate regeneration. We also monitored the fate of (14)C-labeled carbon originating from acetate, butyrate, or bicarbonate in mutants defective in glyoxylate regeneration and identified new potential intermediates in the pathway: ethylmalonyl-CoA, methylsuccinyl-CoA, isobutyryl-CoA, methacrylyl-CoA, and beta-hydroxyisobutyryl-CoA. A new scheme for the pathway is proposed based on these data.
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Affiliation(s)
- Natalia Korotkova
- Department of Chemical Engineering, University of Washington, Seattle, Washington 98195-1750, USA
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122
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Bahnson BJ, Anderson VE, Petsko GA. Structural mechanism of enoyl-CoA hydratase: three atoms from a single water are added in either an E1cb stepwise or concerted fashion. Biochemistry 2002; 41:2621-9. [PMID: 11851409 DOI: 10.1021/bi015844p] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We have determined the crystal structure of the enzyme enoyl-CoA hydratase (ECH) from rat liver with the bound substrate 4-(N,N-dimethylamino)cinnamoyl-CoA using X-ray diffraction data to a resolution of 2.3 A. In addition to the thiolester substrate, the catalytic water, which is added in the hydration reaction, has been modeled into well-defined electron density in each of the six active sites of the physiological hexamer within the crystallographic asymmetric unit. The catalytic water bridges Glu(144) and Glu(164) of the enzyme and has a lone pair of electrons poised to react with C(3) of the enzyme-bound alpha,beta-unsaturated thiolester. The water molecule, which bridges two glutamate residues, is reminiscent of the enolase active site. However, unlike enolase, which has a lysine available to donate a proton, there are no other sources of protons available from other active site residues in ECH. Furthermore, an analysis of the hydrogen-bonding network of the active site suggests that both Glu(144) and Glu(164) are ionized and carry a negative charge with no reasonable place to have a protonated carboxylate. This lack of hydrogen-bonding acceptors that could accommodate a source of a proton, other than from the water molecule, leads to a hypothesis that the three atoms from a single water molecule are added across the double bond to form the hydrated product. The structural results are discussed in connection with details of the mechanism, which have been elucidated from kinetics, site-directed mutagenesis, and spectroscopy of enzyme-substrate species, in presenting an atomic-resolution mechanism of the reaction. Contrary to the previous interpretation, the structure of the E-S complex together with previously determined kinetic isotope effects is consistent with either a concerted mechanism or an E1cb stepwise mechanism.
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Affiliation(s)
- Brian J Bahnson
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA.
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123
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D'Ordine RL, Pawlak J, Bahnson BJ, Anderson VE. Polarization of cinnamoyl-CoA substrates bound to enoyl-CoA hydratase: correlation of (13)C NMR with quantum mechanical calculations and calculation of electronic strain energy. Biochemistry 2002; 41:2630-40. [PMID: 11851410 DOI: 10.1021/bi015845h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
When alpha,beta-unsaturated substrates bind to the active site of enoyl-CoA hydratase, large spectral changes can be observed [D'Ordine, R. L., et al. (1994) Biochemistry 33, 12635-12643]. The differences in the isotropic magnetic shieldings of the free and active site-bound forms of the carbonyl, alpha-, and beta-carbons of the substrates, hexadienoyl-CoA, cinnamoyl-CoA, and (N,N-dimethyl-p-amino)cinnamoyl-CoA have been experimentally determined. The carbonyl and beta-carbons are all deshielded, while the alpha-carbons show increased shielding. These chemical shift perturbations are interpreted to suggest that the pi-electrons of the enoyl thiolester are polarized when bound at the active site. Using the crystal structure of (N,N-dimethyl-p-amino)cinnamoyl-CoA bound at the enzyme active site, the shielding tensors were calculated at three different levels of theory, up to a density functional theory model that included all of the contiguous active site residues. These calculations successfully reproduced the observed spectral changes and permitted the electronic polarization of the substrate to be quantified as an electron density difference map. The calculated electron density difference confirms the loss of electrons at the electrophilic beta-carbon and carbonyl carbon, while a slight increase in electron density at the alpha-carbon where proton donation occurs during the hydration reaction and a larger increase in electron density at the carbonyl oxygen are predicted. The energy required to polarize the electrons to the observed extent was calculated to be 3.2 kcal/mol. The force that provides the requisite energy for the polarization is the interaction of the electric field generated by the protein at the enzyme active site with the polarizable electrons of the substrate. Because the induced electronic polarization is along the predicted reaction pathway, the extent of substrate activation by the induced electronic strain is catalytically relevant.
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Affiliation(s)
- Robert L D'Ordine
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
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124
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Dhar A, Dhar K, Rosazza JPN. Purification and characterization of a Galactomyces reessii hydratase that converts 3-methylcrotonic acid to 3-hydroxy-3-methylbutyric acid. J Ind Microbiol Biotechnol 2002; 28:81-7. [PMID: 12074056 DOI: 10.1038/sj/jim/7000215] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cell free extracts of Galactomyces reessii contain a hydratase as the key enzyme for the transformation of 3-methylcrotonic acid to 3-hydroxy-3-methylbutyric acid. Highest levels of hydratase activity were obtained during growth on isovaleric acid. The enzyme, an enoyl CoA hydratase, was purified 147-fold by precipitation with ammonium sulphate and successive chromatography over columns of DE-52, Blue Sepharose CL-6B and Sephacryl S-200. During purification, hydratase activity was measured spectrophotometrically (OD change at 263 nm) for 3-methylcrotonyl CoA and crotonyl CoA as substrates. The enzyme displayed highest activity with crotonyl CoA with a Kcat of 1,050,000 min(-1). The ratio of crotonyl CoA to 3-methylcrotonyl CoA activities was constant (20:1) during all steps of purification. The Kcat for crotonyl CoA was also about 20 times greater than the Kcat for 3-methylcrotonyl CoA (51,700 min(-1). The enzyme had pH and temperature optima at 7.0 and 35 degrees C, a native Mr of 260 +/- 4.5 kDa and a subunit Mr of 65 kDa, suggesting that the enzyme was a homotetramer. The pI of the purified hydratase was 5.5, and the N-terminal amino acid sequence was VPEGYAEDLLKGKMMRFFDS. Hydratase activity for 3-methylcrotonyl CoA was competitively inhibited by acetyl CoA, propionyl CoA and acetoacetyl CoA.
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Affiliation(s)
- A Dhar
- Division of Medicinal and Natural Products Chemistry, Center For Biocatalysis and Bioprocessing, College of Pharmacy, University of Iowa, Iowa City 52242, USA
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125
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Plaggenborg R, Steinbüchel A, Priefert H. The coenzyme A-dependent, non-beta-oxidation pathway and not direct deacetylation is the major route for ferulic acid degradation in Delftia acidovorans. FEMS Microbiol Lett 2001; 205:9-16. [PMID: 11728709 DOI: 10.1111/j.1574-6968.2001.tb10918.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The gene loci fcs and ech, encoding feruloyl-CoA synthetase and enoyl-CoA hydratase/aldolase, respectively, are involved in the ferulic acid catabolism in Delftia acidovorans. The amino acid sequence deduced from ech exhibited 51% identity to the enoyl-CoA hydratase/aldolase from Pseudomonas sp. strain HR199, indicating that the enzyme from D. acidovorans represents a new lineage of this protein. The genes fcs and ech were expressed in Escherichia coli enabling the recombinant strain to transform ferulic acid to vanillin as revealed by photometric and HPLC analysis. An fcs deficient mutant of D. acidovorans was unable to grow on ferulic acid. The obtained data suggest that in contrast to a previous publication the biotechnologically interesting direct non-oxidative deacetylation mechanism of ferulic acid cleavage is not realized in D. acidovorans. Instead, ferulic acid degradation in D. acidovorans proceeds via a coenzyme A-dependent non-beta-oxidative pathway.
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Affiliation(s)
- R Plaggenborg
- Institut für Mikrobiologie der Westfälischen Wilhelms-Universität Münster, Corrensstrasse 3, D-48149 Münster, Germany
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126
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Haapalainen AM, van Aalten DM, Meriläinen G, Jalonen JE, Pirilä P, Wierenga RK, Hiltunen JK, Glumoff T. Crystal structure of the liganded SCP-2-like domain of human peroxisomal multifunctional enzyme type 2 at 1.75 A resolution. J Mol Biol 2001; 313:1127-38. [PMID: 11700068 DOI: 10.1006/jmbi.2001.5084] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
beta-Oxidation of amino acyl coenzyme A (acyl-CoA) species in mammalian peroxisomes can occur via either multifunctional enzyme type 1 (MFE-1) or type 2 (MFE-2), both of which catalyze the hydration of trans-2-enoyl-CoA and the dehydrogenation of 3-hydroxyacyl-CoA, but with opposite chiral specificity. MFE-2 has a modular organization of three domains. The function of the C-terminal domain of the mammalian MFE-2, which shows similarity with sterol carrier protein type 2 (SCP-2), is unclear. Here, the structure of the SCP-2-like domain comprising amino acid residues 618-736 of human MFE-2 (d Delta h Delta SCP-2L) was solved at 1.75 A resolution in complex with Triton X-100, an analog of a lipid molecule. This is the first reported structure of an MFE-2 domain. The d Delta h Delta SCP-2L has an alpha/beta-fold consisting of five beta-strands and five alpha-helices; the overall architecture resembles the rabbit and human SCP-2 structures. However, the structure of d Delta h Delta SCP-2L shows a hydrophobic tunnel that traverses the protein, which is occupied by an ordered Triton X-100 molecule. The tunnel is large enough to accommodate molecules such as straight-chain and branched-chain fatty acyl-CoAs and bile acid intermediates. Large empty apolar cavities are observed near the exit of the tunnel and between the helices C and D. In addition, the C-terminal peroxisomal targeting signal is ordered in the structure and solvent-exposed, which is not the case with unliganded rabbit SCP-2, supporting the hypothesis of a ligand-assisted targeting mechanism.
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Affiliation(s)
- A M Haapalainen
- Biocenter Oulu and Department of Biochemistry, University of Oulu, FIN-90014, Finland
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127
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Balabanov S, Zimmermann U, Protzel C, Scharf C, Klebingat KJ, Walther R. Tumour-related enzyme alterations in the clear cell type of human renal cell carcinoma identified by two-dimensional gel electrophoresis. Eur J Biochem 2001; 268:5977-80. [PMID: 11722587 DOI: 10.1046/j.0014-2956.2001.02546.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To identify tumour-related enzyme alterations we have used 2D-gels to analyse the proteome from dissected malignant and benign kidney areas from patients with clear-cell-type renal carcinoma. The expression of 12 proteins was diminished in tumour. Four proteins were characterized by mass spectrometry and were identified as enoyl-CoA hydratase, alpha-glycerol-3-phosphate dehydrogenase, aldehyde dehydrogenase 1 and aminoacylase-I.
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Affiliation(s)
- S Balabanov
- Department of Medical Biochemistry and Molecularbiology, University of Greifswald, Germany
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128
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Dakoji S, Li D, Agnihotri G, Zhou HQ, Liu HW. Studies on the inactivation of bovine liver enoyl-CoA hydratase by (methylenecyclopropyl)formyl-CoA: elucidation of the inactivation mechanism and identification of cysteine-114 as the entrapped nucleophile. J Am Chem Soc 2001; 123:9749-59. [PMID: 11583536 DOI: 10.1021/ja011226k] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The inhibitory properties of (methylenecyclopropyl)formyl-CoA (MCPF-CoA), a metabolite derived from a natural amino acid, (methylenecyclopropyl)glycine, against bovine liver enoyl-CoA hydratase (ECH) were characterized. We have previously demonstrated that MCPF-CoA specifically targets ECHs, which catalyze the reversible hydration of alpha,beta-unsaturated enoyl-CoA substrates to the corresponding beta-hydroxyacyl-CoA products. Here, we synthesized (R)- and (S)-diastereomers of MCPF-CoA to examine the stereoselectivity of this inactivation. Both compounds were shown to be competent inhibitors for bovine liver ECH with nearly identical second-order inactivation rate constants (k(inact)/K(I)) and partition ratios (k(cat)/k(inact)), indicating that the inactivation is nonstereospecific with respect to ring cleavage. The inhibitor, upon incubation with bovine liver ECH, labels a tryptic peptide, ALGGGXEL, near the active site of the protein, where X is the amino acid that is covalently modified. Cloning and sequence analysis of bovine liver ECH gene revealed the identity of the amino acid residue entrapped by MCPF-CoA as Cys-114 (mature sequence numbering). On the basis of gHMQC (gradient heteronuclear multiple quantum coherence) analysis with [3-(13)C]-labeled MCPF-CoA, the ring cleavage is most likely induced by the nucleophilic attack at the terminal carbon of the exomethylene group (C(2)'). We propose a plausible inactivation mechanism that involves relief of ring strain and is consistent with examples found in the literature. In addition, these studies provide important clues for future design of more efficient and selective inhibitors to control and/or regulate fatty acid metabolism.
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Affiliation(s)
- S Dakoji
- Division of Medicinal Chemistry, College of Pharmacy, University of Texas, Austin, 78712, USA
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129
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Ishigure K, Shimomura Y, Murakami T, Kaneko T, Takeda S, Inoue S, Nomoto S, Koshikawa K, Nonami T, Nakao A. Human liver disease decreases methacrylyl-CoA hydratase and beta-hydroxyisobutyryl-CoA hydrolase activities in valine catabolism. Clin Chim Acta 2001; 312:115-21. [PMID: 11580916 DOI: 10.1016/s0009-8981(01)00597-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
BACKGROUND Methacrylyl-coenzyme A (MC-CoA) hydratase and beta-hydroxyisobutyryl-coenzyme A (HIB-CoA) hydrolase are key enzymes regulating the toxic concentration of MC-CoA generated in valine catabolism. MATERIALS AND METHODS We studied the activities and mRNA expression levels of these enzymes in normal human livers and in human livers with chronic hepatitis, cirrhosis, or hepatocellular carcinoma. RESULTS The activities of both enzymes were significantly lower by 36% to 46% in livers with cirrhosis or hepatocellular carcinoma compared with normals, suggesting a decrease in the capability of detoxifying MC-CoA with these diseases. The mRNA levels for both enzymes measured by quantitative polymerase chain reaction were significantly increased in livers with cirrhosis, but were not altered in those with chronic hepatitis or hepatocellular carcinoma when compared with normal livers. CONCLUSION Our results suggest that low levels of these enzyme activities in livers with cirrhosis or hepatocellular carcinoma are the result of posttranscriptional regulation in the damaged liver.
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Affiliation(s)
- K Ishigure
- Department of Surgery II, Nagoya University School of Medicine, 466-8550, Nagoya, Japan
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130
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Puyaubert J, Garbay B, Costaglioli P, Dieryck W, Roscoe TJ, Renard M, Cassagne C, Lessire R. Acyl-CoA elongase expression during seed development in Brassica napus. Biochim Biophys Acta 2001; 1533:141-52. [PMID: 11566451 DOI: 10.1016/s1388-1981(01)00152-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The Bn-FAE1.1 and Bn-FAE1.2 genes encode the 3-ketoacyl-CoA synthase, a component of the elongation complex responsible for the synthesis of very long chain monounsaturated fatty acids (VLCMFA) in the seeds of Brassica napus. Bn-FAE1 gene expression was studied during seed development using two different cultivars: Gaspard, a high erucic acid rapeseed (HEAR), and ISLR4, a low erucic acid rapeseed (LEAR). The mRNA developmental profiles were similar for the two cultivars, the maximal expression levels being measured at 8 weeks after pollination (WAP) in HEAR and at 9 WAP in LEAR. Differential expression of Bn-FAE1.1 and Bn-FAE1.2 genes was also studied. In each cultivar the same expression profile was observed for both genes, but Bn-FAE1.2 was expressed at a lower level than Bn-FAE1.1. Secondly, VLCMFA synthesis was measured using particulate fractions prepared from maturating seeds harvested weekly after pollination. The oleoyl-CoA and ATP-dependent elongase activities increased from the 4th WAP in HEAR and reached the maximal level at 8 WAP, whereas both activities were absent in LEAR. In contrast, the 3-hydroxy dehydratase, a subunit of the elongase complex, had a similar activity in both cultivars and reached a maximum from 7 to 9 WAP. Finally, antibodies against the 3-ketoacyl-CoA synthase revealed a protein of 57 kDa present only in HEAR. Our results show: (i) that both genes are transcribed in HEAR and LEAR cultivars; (ii) that they are coordinately regulated; (iii) that Bn-FAE1.1 is quantitatively the major isoform expressed in seeds; (iv) that the Bn-FAE1 gene encodes a protein of 57 kDa responsible for the 3-ketoacyl-CoA synthase activity.
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Affiliation(s)
- J Puyaubert
- Laboratoire de Biogenèse Membranaire, CNRS UMR 5544, Université V. Segalen Bordeaux 2, Bordeaux Cedex, France
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131
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Elssner T, Engemann C, Baumgart K, Kleber HP. Involvement of coenzyme A esters and two new enzymes, an enoyl-CoA hydratase and a CoA-transferase, in the hydration of crotonobetaine to L-carnitine by Escherichia coli. Biochemistry 2001; 40:11140-8. [PMID: 11551212 DOI: 10.1021/bi0108812] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two proteins (CaiB and CaiD) were found to catalyze the reversible biotransformation of crotonobetaine to L-carnitine in Escherichia coli in the presence of a cosubstrate (e.g., gamma-butyrobetainyl-CoA or crotonobetainyl-CoA). CaiB (45 kDa) and CaiD (27 kDa) were purified in two steps to electrophoretic homogeneity from overexpression strains. CaiB was identified as crotonobetainyl-CoA:carnitine CoA-transferase by MALDI-TOF mass spectrometry and enzymatic assays. The enzyme exhibits high cosubstrate specificity to CoA derivatives of trimethylammonium compounds. In particular, the N-terminus of CaiB shows significant identity with other CoA-transferases (e.g., FldA from Clostridium sporogenes, Frc from Oxalobacter formigenes, and BbsE from Thauera aromatica) and CoA-hydrolases (e.g., BaiF from Eubacterium sp.). CaiD was shown to be a crotonobetainyl-CoA hydratase using MALDI-TOF mass spectrometry and enzymatic assays. Besides crotonobetainyl-CoA CaiD is also able to hydrate crotonyl-CoA with a significantly lower Vmax (factor of 10(3)) but not crotonobetaine. The substrate specificity of CaiD and its homology to the crotonase confirm this enzyme as a new member of the crotonase superfamily. Concluding these results, it was verified that hydration of crotonobetaine to L-carnitine proceeds at the CoA level in two steps: the CaiD catalyzed hydration of crotonobetainyl-CoA to L-carnitinyl-CoA, followed by a CoA transfer from L-carnitinyl-CoA to crotonobetaine, catalyzed by CaiB. When gamma-butyrobetainyl-CoA was used as a cosubstrate (CoA donor), the first reaction is the CoA transfer. The optimal ratios of CaiB and CaiD during this hydration reaction, determined to be 4:1 when crotonobetainyl-CoA was used as cosubstrate and 5:1 when gamma-butyrobetainyl-CoA was used as cosubstrate, are different from that found for in vivo conditions (1:3).
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Affiliation(s)
- T Elssner
- Institut für Biochemie, Fakultät für Biowissenschaften, Pharmazie, und Psychologie, Universität Leipzig, Talstrasse 33, D-04103 Leipzig, Germany.
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132
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Cook WS, Jain S, Jia Y, Cao WQ, Yeldandi AV, Reddy JK, Rao MS. Peroxisome proliferator-activated receptor alpha-responsive genes induced in the newborn but not prenatal liver of peroxisomal fatty acyl-CoA oxidase null mice. Exp Cell Res 2001; 268:70-6. [PMID: 11461119 DOI: 10.1006/excr.2001.5266] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Mice deficient in fatty acyl-CoA oxidase (AOX(-/-)), the first enzyme of the peroxisomal beta-oxidation system, develop specific morphological and molecular changes in the liver characterized by microvesicular fatty change, increased mitosis, spontaneous peroxisome proliferation, increased mRNA and protein levels of genes regulated by peroxisome proliferator-activated receptor alpha (PPARalpha), and hepatocellular carcinoma. Based on these findings it is proposed that substrates for AOX function as ligands for PPARalpha. In this study we examined the sequential changes in morphology and gene expression in the liver of wild-type and AOX(-/-) mice at Embryonic Day 17.5, and during postnatal development up to 2 months of age. In AOX(-/-) mice high levels of expression of PPARalpha-responsive genes in the liver commenced on the day of birth and persisted throughout the postnatal period. We found no indication of PPARalpha activation in the livers of AOX(-/-) mice at embryonic age E17.5. In AOX(-/-) mice microvesicular fatty change in liver cells was evident at 7 days. At 2 months of age livers showed extensive steatosis and the presence in the periportal areas of clusters of hepatocytes with abundant granular eosinophilic cytoplasm rich in peroxisomes. These results suggest that the biological ligands for PPARalpha vis a vis substrates for AOX either are not functional in fetal liver or do not cross the placental barrier during the fetal development and that postnatally they are likely derived from milk and diet.
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Affiliation(s)
- W S Cook
- Department of Pathology, Northwestern University Medical School, 303 East Chicago Avenue, Chicago, Illinois 60611, USA
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133
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Laclide-Drouin H, Masutti JP, Hatier R, Dauça M, Grignon G. Effect of clofibrate on the peroxisomes of the intestine of the rat during foetal development. Ital J Anat Embryol 2001; 100 Suppl 1:411-7. [PMID: 11322318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
The aim of the present work was to study the action of clofibrate, known as peroxisomal proliferator, on the intestinal peroxisomes in the foetus of treated pregnant females. The Novikoff technique (catalase activity detection) shows an increase in the number and size of intestinal peroxisomes in the treated females and in the foetus. Significant differences were observed between enterocyte peroxisomal enzymatic activities (catalase and PBE: peroxisomal bifunctional enzyme) in treated and control females on the one hand, and in the foetus of treated and control mothers on the other. The ultrastructural immunocytochemical study of the PPAR (peroxisome proliferator activated receptor) shows labelling of the enterocyte nucleus and mitochondria by the gold particles.
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Affiliation(s)
- H Laclide-Drouin
- Laboratory of Histology of Embryology-Faculty of Medicine, Vandoeuvre-Les-Nancy, France
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134
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Halvorsen B, Rustan AC, Madsen L, Reseland J, Berge RK, Sletnes P, Christiansen EN. Effects of long-chain monounsaturated and n-3 fatty acids on fatty acid oxidation and lipid composition in rats. Ann Nutr Metab 2001; 45:30-7. [PMID: 11244185 DOI: 10.1159/000046703] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Long-chain n-3 fatty acids and fat fish are reported, among multiple physiological properties, to enhance peroxisomal beta-oxidation and effect triacylglycerol status. Long-chain n-3 and monounsaturated fatty acids are the main portion of fatty acids in fat fish. The individual effect of long-chain monounsaturated fatty acids on beta-oxidation and fatty acid composition was tested and compared to the effect of n-3 polyunsaturated and saturated fatty acids in a 3-week feeding experiment of rats. To explore the contribution from long-chain monounsaturated fatty acids in these aspects, the effect of long-chain n-3 and monounsaturated fatty acids on mitochondrial and peroxisomal beta-oxidation was compared, as well as fatty acid composition of adipose tissue, liver and serum. Fatty acid oxidase, palmitoyltransferase I and II activities, the amount of serum lipids, and the fatty acid composition of lipid fractions from the organs were analysed. The peroxisomal beta-oxidation was enhanced by the n-3 fatty acids, whereas a small, significant increase with the monounsaturated fatty acids was observed. There was a stimulation of the mitochondrial oxidation with the n-3 fatty acids, but monounsaturated fatty acids gave a small, nonsignificant decrease. With n-3 fatty acids there was a considerable decrease in the levels of serum triacylglycerol, phospholipids, free fatty acids and total cholesterol, while there were only minor effects of monounsaturated fatty acids. As judged from the fatty acid composition data, there was a mobilization on n-3 fatty acids from the adipose tissue to liver and plasma with the n-3 diet. This observation was also seen with the monounsaturated fatty acid-enriched diet. In conclusion, monounsaturated fatty acids seemed to stimulate peroxisomal beta-oxidation and to increase plasma triacylglycerol, whereas the mitochondrial oxidation was slightly decreased.
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Affiliation(s)
- B Halvorsen
- Institute for Nutrition Research, University of Oslo, Norway
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135
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Kunin V, Chan B, Sitbon E, Lithwick G, Pietrokovski S. Consistency analysis of similarity between multiple alignments: prediction of protein function and fold structure from analysis of local sequence motifs. J Mol Biol 2001; 307:939-49. [PMID: 11273712 DOI: 10.1006/jmbi.2001.4466] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A new method to analyze the similarity between multiply aligned protein motifs (blocks) was developed. It identifies sets of consistently aligned blocks. These are found to be protein regions of similar function and structure that appear in different contexts. For example, the Rossmann fold ligand-binding region is found similar to TIM barrel and methylase regions, various protein families are predicted to have a TIM-barrel fold and the structural relation between the ClpP protease and crotonase folds is identified from their sequence. Besides identifying local structure features, sequence similarity across short sequence-regions (less than 20 amino acid regions) also predicts structure similarity of whole domains (folds) a few hundred amino acid residues long. Most of these relations could not be identified by other advanced sequence-to-sequence or sequence-to-multiple alignments comparisons. We describe the method (termed CYRCA), present examples of our findings, and discuss their implications.
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Affiliation(s)
- V Kunin
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, 76100, Israel
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136
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Chen G, Huang LD, Zeng WZ, K Manji H. Mood stabilizers regulate cytoprotective and mRNA-binding proteins in the brain: long-term effects on cell survival and transcript stability. Int J Neuropsychopharmacol 2001; 4:47-64. [PMID: 11343630 DOI: 10.1017/s146114570100222x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2000] [Revised: 11/27/2000] [Indexed: 11/05/2022] Open
Abstract
Manic depressive illness (MDI) is a common, severe, chronic and often life-threatening illness. Despite well-established genetic diatheses and extensive research, the biochemical abnormalities underlying the predisposition to, and the pathophysiology of, these disorders remain to be clearly established. Despite formidable obstacles in our attempts to understand the underlying neurobiology of this illness, there is currently considerable excitement about the progress that is being made using novel strategies to identify changes in gene expression that may have therapeutic relevance in the long-term treatment of MDI. In this paper, we describe our recent research endeavours utilizing newer technologies, including a concerted series of mRNA RT-PCR studies, which has led to the identification of novel, hitherto completely unexpected targets for the long-term actions of mood stabilizers - the major cytoprotective protein bcl-2, a human mRNA binding (and stabilizing) protein, AUH, and a Rho kinase. These results add to the growing body of data suggesting that mood stabilizers may bring about some of their long-term benefits by enhancing neuroplasticity and cellular resilience. These results are noteworthy since recent morphometric brain imaging and post-mortem studies have demonstrated that MDI is associated with the atrophy and/or loss of neurons and glia. The development of novel treatments which more directly target molecules involved in critical CNS cell survival and cell death pathways have the potential to enhance neuroplasticity and cellular resilience, and thereby modulate the long-term course and trajectory of these devastating illnesses.
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Affiliation(s)
- G Chen
- Laboratory of Molecular Pathophysiology, NIMH Bethesda, MD 20892-4405, USA
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137
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Watson RR, Dickson KA. Enzyme activities support the use of liver lipid-derived ketone bodies as aerobic fuels in muscle tissues of active sharks. Physiol Biochem Zool 2001; 74:273-82. [PMID: 11247746 DOI: 10.1086/319667] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Few data exist to test the hypothesis that elasmobranchs utilize ketone bodies rather than fatty acids for aerobic metabolism in muscle, especially in continuously swimming, pelagic sharks, which are expected to be more reliant on lipid fuel stores during periods between feeding bouts and due to their high aerobic metabolic rates. Therefore, to provide support for this hypothesis, biochemical indices of lipid metabolism were measured in the slow-twitch, oxidative (red) myotomal muscle, heart, and liver of several active shark species, including the endothermic shortfin mako, Isurus oxyrinchus. Tissues were assayed spectrophotometrically for indicator enzymes of fatty acid oxidation (3-hydroxy-o-acyl-CoA dehydrogenase), ketone-body catabolism (3-oxoacid-CoA transferase), and ketogenesis (hydroxy-methylglutaryl-CoA synthase). Red muscle and heart had high capacities for ketone utilization, low capacities for fatty acid oxidation, and undetectable levels of ketogenic enzymes. Liver demonstrated undetectable activities of ketone catabolic enzymes but high capacities for fatty acid oxidation and ketogenesis. Serum concentrations of the ketone beta-hydroxybutyrate varied interspecifically (means of 0.128-0.978 micromol mL(-1)) but were higher than levels previously reported for teleosts. These results are consistent with the hypothesis that aerobic metabolism in muscle tissue of active sharks utilizes ketone bodies, and not fatty acids, derived from liver lipid stores.
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Affiliation(s)
- R R Watson
- Department of Biological Science, California State University-Fullerton, Fullerton, CA 92834, USA
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138
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Abstract
Raman spectroscopy has been used to investigate the structure of a substrate analogue, hexadienoyl-CoA (HD-CoA), bound to wild-type enoyl-CoA hydratase and G141P, a mutant in which a hydrogen bond to the substrate carbonyl has been removed. Raman spectra of isotopically labeled HD-CoAs, together with normal mode calculations, confirm the selective ground-state polarization of the enone fragment previously suggested to occur on binding to the wild-type enzyme [Tonge, P. J., Anderson, V. E., Fausto, R., Kim, M., Pusztai-Carey, M., and Carey, P. R. (1995) Biospectroscopy 1, 387-394]. In addition, Raman spectra of HD-CoA bound to the G141P mutant enzyme demonstrate that the hydrogen bond between the G141 amide NH group and the substrate carbonyl is critical for polarization and activity. Replacement of G141 with proline results in an approximately 10(6)-fold decrease in k(cat) and eliminates the ability of the enzyme to polarize the substrate analogue. As G141 is part of a consensus sequence in the enoyl-CoA hydratase superfamily, the results presented here provide direct evidence for the importance of the oxyanion hole in the reactions catalyzed by other family members.
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Affiliation(s)
- A F Bell
- Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400, USA
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139
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Holden HM, Benning MM, Haller T, Gerlt JA. The crotonase superfamily: divergently related enzymes that catalyze different reactions involving acyl coenzyme a thioesters. Acc Chem Res 2001; 34:145-57. [PMID: 11263873 DOI: 10.1021/ar000053l] [Citation(s) in RCA: 139] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Synergistic investigations of the reactions catalyzed by several members of an enzyme superfamily provide a more complete understanding of the relationships between structure and function than is possible from focused studies of a single enzyme alone. The crotonase (or enoyl-CoA hydratase) superfamily is such an example whereby members catalyze a wide range of metabolic reactions but share a common structural solution to a mechanistic problem. Some enzymes in the superfamily have been shown to display dehalogenase, hydratase, and isomerase activities. Others have been implicated in carbon-carbon bond formation and cleavage as well as the hydrolysis of thioesters. While seemingly unrelated mechanistically, the common theme in this superfamily is the need to stabilize an enolate anion intermediate derived from an acyl-CoA substrate. This apparently is accomplished by two structurally conserved peptidic NH groups that provide hydrogen bonds to the carbonyl moieties of the acyl-CoA substrates and form an "oxyanion hole".
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Affiliation(s)
- H M Holden
- Departments of Biochemistry, University of Illinois, Urbana, Illinois 61801, USA.
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140
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Affiliation(s)
- M Dai
- Department of Chemistry and Graduate Programs in Biophysics, SUNY at Stony Brook Stony Brook, New York 11794-3400, USA
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141
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Juge-Aubry CE, Kuenzli S, Sanchez JC, Hochstrasser D, Meier CA. Peroxisomal bifunctional enzyme binds and activates the activation function-1 region of the peroxisome proliferator-activated receptor alpha. Biochem J 2001; 353:253-8. [PMID: 11139388 PMCID: PMC1221566 DOI: 10.1042/0264-6021:3530253] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The transcriptional activity of peroxisome proliferator-activated receptors (PPARs), and of nuclear hormone receptors in general, is subject to modulation by cofactors. However, most currently known co-activating proteins interact in a ligand-dependent manner with the C-terminal ligand-regulated activation function (AF)-2 domain of nuclear receptors. Since PPARalpha exhibits a strong constitutive transactivating function contained within an N-terminal AF-1 region, it can be speculated that a different set of cofactors might interact with this region of PPARs. An affinity purification approach was used to identify the peroxisomal enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase (bifunctional enzyme, BFE) as a protein which strongly and specifically interacted with the N-terminal 92 amino acids of PPARalpha. Protein-protein interaction assays with the cloned BFE confirmed this interaction, which could be mapped to amino acids 307-514 of the BFE and the N-terminal 70 amino acids of PPARalpha. Moreover, transient transfection experiments in hepatoma cells revealed a 2.2-fold increase in the basal and ligand-stimulated transcriptional activity of PPARalpha in the presence of BFE. This stimulatory effect is preferentially observed for the PPARalpha isoform and it is significantly stronger (4.8-fold) in non-hepatic cells, which presumably express lower levels of endogenous BFE. Hence, the BFE represents the first known cofactor capable of activating the AF-1 domain of PPAR without requiring additional regions of this receptor. These data are compatible with a model whereby the PPAR-regulated BFE is able to modulate its own expression through an enhancement of the activity of PPARalpha, representing a novel peroxisomal-nuclear feed-forward regulatory loop.
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Affiliation(s)
- C E Juge-Aubry
- Division of Endocrinology and Diabetes, Department of Medicine, University Hospital Geneva, 24 rue Micheli-du-Crest, CH-1211 Geneva 14, Switzerland
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142
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Abstract
Degradation of trans-unsaturated fatty acids was studied in the yeast Saccharomyces cerevisiae. Propagation of yeast cells on trans-9 elaidic acid medium resulted in transcriptional up-regulation of the SPS19 gene, whose promoter contains an oleate response element. This up-regulation depended on the Pip2p-Oaf1p transcription factor and was accompanied by induction of import-competent peroxisomes. Utilization of trans fatty acids as a single carbon and energy source was evaluated by monitoring the formation of clear zones around cell growth on turbid media containing fatty acids dispersed with Tween 80. For metabolizing odd-numbered trans double bonds, cells required the beta-oxidation auxiliary enzyme Delta(3)-Delta(2)-enoyl-CoA isomerase Eci1p. Metabolism of the corresponding even-numbered double bonds proceeded in the absence of Sps19p (2,4-dienoyl-CoA reductase) and Dci1p (Delta(3,5)-Delta(2,4)-dienoyl-CoA isomerase). trans-2,trans-4-Dienoyl-CoAs could enter beta-oxidation directly via Fox2p (2-enoyl-CoA hydratase 2 and d-specific 3-hydroxyacyl-CoA dehydrogenase) without the involvement of Sps19p, whereas trans-2,cis-4-dienoyl-CoAs could not. This reductase-independent metabolism of trans-2,trans-4-dienoyl-CoAs resembled the situation postulated for mammalian mitochondria in which oleic acid is degraded through a di-isomerase-dependent pathway. In this hypothetical process, trans-2,trans-4-dienoyl-CoA metabolites are generated by Delta(3)-Delta(2)-enoyl-CoA isomerase and Delta(3,5)-Delta(2,4)-dienoyl-CoA isomerase and are degraded by 2-enoyl-CoA hydratase 1 in the absence of 2,4-dienoyl-CoA reductase. Growth of a yeast fox2sps19Delta mutant in which Fox2p was exchanged with rat peroxisomal multifunctional enzyme type 1 on trans-9,trans-12 linolelaidic acid medium gave credence to this theory. We propose an amendment to the current scheme of the carbon flux through beta-oxidation taking into account the dispensability of beta-oxidation auxiliary enzymes for metabolizing trans double bonds at even-numbered positions.
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Affiliation(s)
- A Gurvitz
- Institut für Biochemie und Molekulare Zellbiologie der Universität Wien and Ludwig Boltzmann-Forschungsstelle für Biochemie, Vienna Biocenter, Dr Bohrgasse 9, A-1030 Vienna, Austria.
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143
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Duscha BD, Annex BH, Keteyian SJ, Green HJ, Sullivan MJ, Samsa GP, Brawner CA, Schachat FH, Kraus WE. Differences in skeletal muscle between men and women with chronic heart failure. J Appl Physiol (1985) 2001; 90:280-6. [PMID: 11133920 DOI: 10.1152/jappl.2001.90.1.280] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Men with chronic heart failure (CHF) have alterations in their skeletal muscle that are partially responsible for a decreased exercise tolerance. The purpose of this study was to investigate whether skeletal muscle alterations in women with CHF are similar to those observed in men and if these alterations are related to exercise intolerance. Twenty-five men and thirteen women with CHF performed a maximal exercise test for evaluation of peak oxygen consumption (VO(2)) and resting left ventricular ejection fraction, after which a biopsy of the vastus lateralis was performed. Twenty-one normal subjects (11 women, 10 men) were also studied. The relationship between muscle markers and peak VO(2) was consistent for CHF men and women. When controlling for gender, analysis showed that oxidative enzymes and capillary density are the best predictors of peak VO(2.) These results indicate that aerobically matched CHF men and women have no differences in skeletal muscle biochemistry and histology. However, when CHF groups were separated by peak exercise capacity of 4.5 metabolic equivalents (METs), CHF men with peak VO(2) >4.5 METs had increased citrate synthase and 3-hydroxyacyl-CoA dehydrogenase compared with CHF men with peak VO(2) <4.5 METs. CHF men with a lower peak VO(2) had increased capillary density compared with men with higher peak VO(2). These observations were not reproduced in CHF women. This suggests that differences may exist in how skeletal muscle adapts to decreasing peak VO(2) in patients with CHF.
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Affiliation(s)
- B D Duscha
- Division of Cardiology, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA.
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144
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Park SJ, Ahn WS, Green PR, Lee SY. Biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) by metabolically engineeredEscherichia coli strains. Biotechnol Bioeng 2001; 74:81-6. [PMID: 11353413 DOI: 10.1002/bit.1097] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The recombinant Escherichia coli strain, equipped with the newly cloned Aeromonas PHA biosynthesis genes, could produce a terpolymer of 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), and 3-hydroxyhexanoate (3HHx) [P(3HB-co-3HV-co-3HHx)] from dodecanoic acid plus odd carbon number fatty acid. In addition, the orf1 gene of Aeromonas hydrophila was found to play a critical role in assimilating the 3HV monomer and in regulating the monomer fraction in the terpolymer.
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Affiliation(s)
- S J Park
- Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical Engineering and BioProcess Engineering Research Center, Korea Advanced Institute of Science and Technology, 373-1 Kusong-dong, Yusong-gu, Taejon 305-701, Korea
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145
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Fengsrud M, Raiborg C, Berg TO, Strømhaug PE, Ueno T, Erichsen ES, Seglen PO. Autophagosome-associated variant isoforms of cytosolic enzymes. Biochem J 2000; 352 Pt 3:773-781. [PMID: 11104685 DOI: 10.1042/0264-6021:3520773] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
In a search for autophagosome-associated proteins, two-dimensional gel separations of proteins from purified autophagosomes, postnuclear supernatant, cytosol, lysosomes, mitochondria, endosomes and a cytomembrane fraction (mostly endoplasmic reticulum) were compared. Three proteins, with monomeric molecular masses of 43, 35 and 31 kDa, were enriched in total or sedimentable fractions of autophagosomes relative to the corresponding fractions of postnuclear supernatant, suggesting an association with the autophagosomal delimiting membrane. These proteins were also present on lysosomal membranes, but they were absent from mitochondria, and detected only in small amounts in the cytomembrane fraction and in endosomes, indicating that they were not associated with organelles sequestered by autophagy. However, all three proteins were present in the cytosol, suggesting that they were cytosolic proteins binding peripherally to the delimiting membrane of autophagosomes, probably to its innermost surface as indicated by their resistance to treatment of intact autophagosomes with proteinase or protein-stripping agents. Amino acid sequencing identified these proteins as an isoform of argininosuccinate synthase, an N-truncated variant of glyceraldehyde-3-phosphate dehydrogenase, and a sequence variant of short-chain 2-enoyl-CoA hydratase.
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Affiliation(s)
- M Fengsrud
- Department of Cell Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Montebello, N-0310 Oslo, Norway
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146
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Achterholt S, Priefert H, Steinbüchel A. Identification of Amycolatopsis sp. strain HR167 genes, involved in the bioconversion of ferulic acid to vanillin. Appl Microbiol Biotechnol 2000; 54:799-807. [PMID: 11152072 DOI: 10.1007/s002530000431] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The gene loci ech, encoding enoyl-CoA hydratase/aldolase, and fcs, encoding an unusual feruloyl-CoA synthetase, which are involved in the bioconversion of ferulic acid to vanillin by the gram-positive bacterium Amycolatopsis sp. strain HR167, were localized on a 4,000 bp PstI fragment (P40). The nucleotide sequence of P40 was determined, revealing open reading frames of 864 bp and 1,476 bp, representing ech and fcs, respectively. The deduced amino acid sequences of ech exhibited 62% amino acid identity to the enoyl-CoA hydratase/aldolase from Pseudomonas sp. strain HR199 and the enoyl-CoA hydratase/lyase from P. fluorescens strain AN103. The deduced amino acid sequences of fcs exhibited up to 37% amino acid identity to long-chain fatty acid coenzymeA ligases but no significant similarity to the feruloyl-CoA synthetase of Pseudomonas sp. strain HR199. Fragment P40 was cloned in pBluescript SK- and fcs and ech were expressed in Escherichia coli. Recombinant strains were able to transform ferulic acid to vanillin. In crude extracts of these recombinant strains, feruloyl-CoA synthetase and enoyl-CoA hydratase/aldolase activities were detected by photometric assay and high-performance liquid chromatography. The obtained data suggest that ferulic acid degradation in the gram-positive Amycolatopsis sp. strain HR167 proceeds via a pathway similar to that recently described for the gram-negative P. fluorescens strain AN103 and Pseudomonas sp. strain HR199.
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Affiliation(s)
- S Achterholt
- Institut für Mikrobiologie der Westfälischen Wilhelms-Universität Münster, Germany
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147
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Baker-Malcolm JF, Lantz M, Anderson VE, Thorpe C. Novel inactivation of enoyl-CoA hydratase via beta-elimination of 5, 6-dichloro-7,7,7-trifluoro-4-thia-5-heptenoyl-CoA. Biochemistry 2000; 39:12007-18. [PMID: 11009615 DOI: 10.1021/bi0010165] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
5,6-Dichloro-7,7,7-trifluoro-4-thia-5-heptenoyl-CoA (DCTFTH-CoA) is an analogue of a class of cytotoxic 4-thiaacyl-CoA thioesters that can undergo a beta-elimination reaction to form highly unstable thiolate fragments, which yield electrophilic thioketene or thionoacyl halide species. Previous work demonstrated that the medium-chain acyl-CoA dehydrogenase both bioactivates and is inhibited by these CoA thioesters through enzyme-catalyzed beta-elimination of the reactive thiolate moiety [Baker-Malcolm, J. F., Haeffner-Gormley, L., Wang, L., Anders, M. W., and Thorpe, C. (1998) Biochemistry 37, 1383-1393]. This paper shows that DCTFTH-CoA can be directly bioactivated by the enoyl-CoA hydratase (ECH) with the release of 1,2-dichloro-3,3,3-trifluoro-1-propenethiolate and acryloyl-CoA. In the absence of competing exogenous trapping agents, DCTFTH-CoA effects rapid and irreversible loss of hydratase activity. The inactivator is particularly effective at pH 9.0, with a stoichiometry approaching 1 mol of DCTFTH-CoA per enzyme subunit. Modification is associated with a new protein-bound chromophore at 360 nm and an increase in mass of 89 +/- 5 per subunit. Surprisingly, ECH exhibiting less than 2% residual hydratase activity retains essentially 100% beta-eliminase activity and continues to generate reactive thiolate species from DCTFTH-CoA. This leads to progressive derivatization of the enzyme with additional UV absorbance, covalent cross-linking of subunits, and an eventual complete loss of beta-eliminase activity. A range of exogenous trapping agents, including small thiol nucleophiles, various proteins, and even phospholipid bilayers, exert strong protection against modification of ECH. Peptide mapping, thiol titrations, UV-vis spectrophotometry, and mass spectrometry show that inactivation involves the covalent modification of Cys62 and/or Cys111 of the recombinant rat liver ECH. These data suggest that enoyl-CoA hydratase is an important enzyme in the bioactivation of DCTFTH-CoA, in a pathway which does not require involvement of the medium-chain acyl-CoA dehydrogenase.
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Affiliation(s)
- J F Baker-Malcolm
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA
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148
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Abstract
Trichloroethylene is a widespread industrial solvent and one of the most common environmental contaminants. Trichloroethylene causes hepatocarcinoma in the B6C3F1 mouse in a dose-dependent manner. Trichloroethylene's hepatocarcinogenicity is thought to be mediated through its metabolites trichloroacetate and dichloroacetate. Although the mechanism of action is not well understood, hepatic tumors are thought to arise as a result of excessive peroxisome-dependent active oxygen production or secondary to enhanced cell replication. The peroxisome proliferative activity of trichloroacetate has been replicated in cultured rodent hepatocytes, while that of dichloroacetate has not been demonstrated. The present experiments were designed to characterize the peroxisome proliferative response to dichloroacetate in hepatocyte cultures from male B6C3F1 mice and male Long Evans rats. The cultured hepatocytes were treated after attachment with 0.1, 0.5, 1.0, 2.0, or 4.0 mM dichloroacetate for 72 hours. Peroxisome proliferation was assessed by measuring palmitoyl-CoA oxidation and by immunoquantitation of peroxisomal bifunctional enzyme. Palmitoyl CoA oxidation increased in a concentration-dependent manner, with maximal induction of 5.5- and 5-fold in mouse and rat hepatocytes, respectively, after treatment with 2.0 mM dichloroacetate. Peroxisomal bifunctional enzyme protein levels also increased in a concentration-dependent manner in both rat and mouse hepatocytes in response to dichloroacetate exposure. These results indicate that the peroxisomal response observed in vivo in response to dichloroacetate administration can be reproduced in primary cultures of rat and mouse hepatocytes treated with dichloroacetate. Further studies using this model system will help elucidate mechanisms of dichloroacetate-induced hepatocarcinogenesis.
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Affiliation(s)
- J L Everhart
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston 29425, USA
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149
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Smith JJ, Brown TW, Eitzen GA, Rachubinski RA. Regulation of peroxisome size and number by fatty acid beta -oxidation in the yeast yarrowia lipolytica. J Biol Chem 2000; 275:20168-78. [PMID: 10787422 DOI: 10.1074/jbc.m909285199] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The Yarrowia lipolytica MFE2 gene encodes peroxisomal beta-oxidation multifunctional enzyme type 2 (MFE2). MFE2 is peroxisomal in a wild-type strain but is cytosolic in a strain lacking the peroxisomal targeting signal-1 (PTS1) receptor. MFE2 has a PTS1, Ala-Lys-Leu, that is essential for targeting to peroxisomes. MFE2 lacking a PTS1 can apparently oligomerize with full-length MFE2 to enable targetting to peroxisomes. Peroxisomes of an oleic acid-induced MFE2 deletion strain, mfe2-KO, are larger and more abundant than those of the wild-type strain. Under growth conditions not requiring peroxisomes, peroxisomes of mfe2-KO are larger but less abundant than those of the wild-type strain, suggesting a role for MFE2 in the regulation of peroxisome size and number. A nonfunctional version of MFE2 did not restore normal peroxisome morphology to mfe2-KO cells, indicating that their phenotype is not due to the absence of MFE2. mfe2-KO cells contain higher amounts of beta-oxidation enzymes than do wild-type cells. We also show that increasing the level of the beta-oxidation enzyme thiolase results in enlarged peroxisomes. Our results implicate peroxisomal beta-oxidation in the control of peroxisome size and number in yeast.
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Affiliation(s)
- J J Smith
- Department of Cell Biology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
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150
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Baes M, Huyghe S, Carmeliet P, Declercq PE, Collen D, Mannaerts GP, Van Veldhoven PP. Inactivation of the peroxisomal multifunctional protein-2 in mice impedes the degradation of not only 2-methyl-branched fatty acids and bile acid intermediates but also of very long chain fatty acids. J Biol Chem 2000; 275:16329-36. [PMID: 10748062 DOI: 10.1074/jbc.m001994200] [Citation(s) in RCA: 151] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
According to current views, peroxisomal beta-oxidation is organized as two parallel pathways: the classical pathway that is responsible for the degradation of straight chain fatty acids and a more recently identified pathway that degrades branched chain fatty acids and bile acid intermediates. Multifunctional protein-2 (MFP-2), also called d-bifunctional protein, catalyzes the second (hydration) and third (dehydrogenation) reactions of the latter pathway. In order to further clarify the physiological role of this enzyme in the degradation of fatty carboxylates, MFP-2 knockout mice were generated. MFP-2 deficiency caused a severe growth retardation during the first weeks of life, resulting in the premature death of one-third of the MFP-2(-/-) mice. Furthermore, MFP-2-deficient mice accumulated VLCFA in brain and liver phospholipids, immature C(27) bile acids in bile, and, after supplementation with phytol, pristanic and phytanic acid in liver triacylglycerols. These changes correlated with a severe impairment of peroxisomal beta-oxidation of very long straight chain fatty acids (C(24)), 2-methyl-branched chain fatty acids, and the bile acid intermediate trihydroxycoprostanic acid in fibroblast cultures or liver homogenates derived from the MFP-2 knockout mice. In contrast, peroxisomal beta-oxidation of long straight chain fatty acids (C(16)) was enhanced in liver tissue from MFP-2(-/-) mice, due to the up-regulation of the enzymes of the classical peroxisomal beta-oxidation pathway. The present data indicate that MFP-2 is not only essential for the degradation of 2-methyl-branched fatty acids and the bile acid intermediates di- and trihydroxycoprostanic acid but also for the breakdown of very long chain fatty acids.
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Affiliation(s)
- M Baes
- Laboratory of Clinical Chemistry and Laboratory of Pharmacology, K. U. Leuven, Herestraat 49 O/N, B 3000 Leuven, Belgium.
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