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Hasan SMN, Lou JW, Keszei AFA, Dai DL, Mazhab-Jafari MT. Atomic model for core modifying region of human fatty acid synthase in complex with Denifanstat. Nat Commun 2023; 14:3460. [PMID: 37308485 DOI: 10.1038/s41467-023-39266-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 05/31/2023] [Indexed: 06/14/2023] Open
Abstract
Fatty acid synthase (FASN) catalyzes the de novo synthesis of palmitate, a 16-carbon chain fatty acid that is the primary precursor of lipid metabolism and an important intracellular signaling molecule. FASN is an attractive drug target in diabetes, cancer, fatty liver diseases, and viral infections. Here, we develop an engineered full-length human FASN (hFASN) that enables isolation of the condensing and modifying regions of the protein post-translation. The engineered protein enables electron cryo-microscopy (cryoEM) structure determination of the core modifying region of hFASN to 2.7 Å resolution. Examination of the dehydratase dimer within this region reveals that unlike its close homolog, porcine FASN, the catalytic cavity is close-ended and is accessible only through one opening in the vicinity of the active site. The core modifying region exhibits two major global conformational variabilities that describe long-range bending and twisting motions of the complex in solution. Finally, we solved the structure of this region bound to an anti-cancer drug, Denifanstat (i.e., TVB-2640), demonstrating the utility of our approach as a platform for structure guided design of future hFASN small molecule inhibitors.
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Affiliation(s)
- S M Naimul Hasan
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Jennifer W Lou
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Alexander F A Keszei
- Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, Canada
| | - David L Dai
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Mohammad T Mazhab-Jafari
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
- Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, Canada.
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2
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Vanauberg D, Schulz C, Lefebvre T. Involvement of the pro-oncogenic enzyme fatty acid synthase in the hallmarks of cancer: a promising target in anti-cancer therapies. Oncogenesis 2023; 12:16. [PMID: 36934087 PMCID: PMC10024702 DOI: 10.1038/s41389-023-00460-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 03/01/2023] [Accepted: 03/03/2023] [Indexed: 03/20/2023] Open
Abstract
An accelerated de novo lipogenesis (DNL) flux is a common characteristic of cancer cells required to sustain a high proliferation rate. The DNL enzyme fatty acid synthase (FASN) is overexpressed in many cancers and is pivotal for the increased production of fatty acids. There is increasing evidences of the involvement of FASN in several hallmarks of cancer linked to its ability to promote cell proliferation via membranes biosynthesis. In this review we discuss about the implication of FASN in the resistance to cell death and in the deregulation of cellular energetics by increasing nucleic acids, protein and lipid synthesis. FASN also promotes cell proliferation, cell invasion, metastasis and angiogenesis by enabling the building of lipid rafts and consequently to the localization of oncogenic receptors such as HER2 and c-Met in membrane microdomains. Finally, FASN is involved in immune escape by repressing the activation of pro-inflammatory cells and promoting the recruitment of M2 macrophages and T regulatory cells in the tumor microenvironment. Here, we provide an overview of the involvement of the pro-oncogenic enzyme in the hallmarks of cancer making FASN a promising target in anti-cancer therapy to circumvent resistance to chemotherapies.
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Affiliation(s)
- Dimitri Vanauberg
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
| | - Céline Schulz
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
| | - Tony Lefebvre
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France.
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3
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Paiva P, Medina FE, Viegas M, Ferreira P, Neves RPP, Sousa JPM, Ramos MJ, Fernandes PA. Animal Fatty Acid Synthase: A Chemical Nanofactory. Chem Rev 2021; 121:9502-9553. [PMID: 34156235 DOI: 10.1021/acs.chemrev.1c00147] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Fatty acids are crucial molecules for most living beings, very well spread and conserved across species. These molecules play a role in energy storage, cell membrane architecture, and cell signaling, the latter through their derivative metabolites. De novo synthesis of fatty acids is a complex chemical process that can be achieved either by a metabolic pathway built by a sequence of individual enzymes, such as in most bacteria, or by a single, large multi-enzyme, which incorporates all the chemical capabilities of the metabolic pathway, such as in animals and fungi, and in some bacteria. Here we focus on the multi-enzymes, specifically in the animal fatty acid synthase (FAS). We start by providing a historical overview of this vast field of research. We follow by describing the extraordinary architecture of animal FAS, a homodimeric multi-enzyme with seven different active sites per dimer, including a carrier protein that carries the intermediates from one active site to the next. We then delve into this multi-enzyme's detailed chemistry and critically discuss the current knowledge on the chemical mechanism of each of the steps necessary to synthesize a single fatty acid molecule with atomic detail. In line with this, we discuss the potential and achieved FAS applications in biotechnology, as biosynthetic machines, and compare them with their homologous polyketide synthases, which are also finding wide applications in the same field. Finally, we discuss some open questions on the architecture of FAS, such as their peculiar substrate-shuttling arm, and describe possible reasons for the emergence of large megasynthases during evolution, questions that have fascinated biochemists from long ago but are still far from answered and understood.
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Affiliation(s)
- Pedro Paiva
- LAQV, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Fabiola E Medina
- Departamento de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Autopista Concepción-Talcahuano, 7100 Talcahuano, Chile
| | - Matilde Viegas
- LAQV, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Pedro Ferreira
- LAQV, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Rui P P Neves
- LAQV, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - João P M Sousa
- LAQV, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Maria J Ramos
- LAQV, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Pedro A Fernandes
- LAQV, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
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Oppong MB, Li Y, Banahene PO, Fang SM, Qiu F. Ethnopharmacology, phytochemistry, and pharmacology of Sterculia lychnophora Hance (Pangdahai). Chin J Nat Med 2018; 16:721-731. [PMID: 30322606 DOI: 10.1016/s1875-5364(18)30112-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Indexed: 10/28/2022]
Abstract
The matured, ripen, and dried seeds of Scaphium affine (Mast.) Pierre, known as Pangdahai (PDH) in Chinese and recorded as Sterculia lychnophora Hance (scientific synonym) in the 2015 edition of the Chinese Pharmacopeia, have been widely used in traditional Chinese medicine, Japanese folk medicine, Vietnamese traditional medicine, traditional Thai medicine and Indian traditional medicine. The decoctions of the seeds are used as a remedy for pharyngitis, laryngitis, constipation, cough, menorrhagia, and pain management. This review is aimed at fully collating and presenting a systematic and comprehensive overview of the ethnopharmacological uses of PDH, its phytochemical constituents, pharmacological activities, and toxicological profile. Additionally, this review aims to reveal the therapeutic potentials as well as the important scientific gaps in the research of this traditional medicine that need to be filled so as to provide a comprehensive data for its development, utilization and application. From our extensive review of literatures, the teas (water decoctions) of PDH, which largely contain very polar constituents like polysaccharides, are used in the treatment of constipation, pharyngitis, and pain traditionally and ethno-medicinally and their use have been justified by pharmacological studies carried out on the polysaccharides and aqueous extracts. Additionally, this review has revealed that the organic (ethanolic and methanolic) extracts of PDH possess diverse pharmacological (anti-inflammatory, anti-ulcer, anti-pyretic, anti-microbial, anti-obesity and analgesic) effects, yet have received little attention. Most studies on PDH have been focused on the polysaccharides (large molecular weight metabolites), resulting in a major scientific gap in our knowledge on PDH. Furthermore, this review has also shown that few studies have been done in the areas of quality control, pharmacokinetics, and toxicological studies of PDH.
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Affiliation(s)
- Mahmood Brobbey Oppong
- Tianjin State Key Laboratory of Modern Chinese Medicine and School of Chinese Materia Medica, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, China; Department of Pharmaceutical Chemistry, School of Pharmacy, College of Health Sciences, University of Ghana, P.O. Box, LG 43, Legon, Ghana
| | - Yang Li
- Tianjin State Key Laboratory of Modern Chinese Medicine and School of Chinese Materia Medica, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, China
| | - Prince Osei Banahene
- Tianjin State Key Laboratory of Modern Chinese Medicine and School of Chinese Materia Medica, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, China
| | - Shi-Ming Fang
- Tianjin State Key Laboratory of Modern Chinese Medicine and School of Chinese Materia Medica, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, China.
| | - Feng Qiu
- Tianjin State Key Laboratory of Modern Chinese Medicine and School of Chinese Materia Medica, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, China.
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5
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Abstract
Covering: up to mid of 2018 Type I fatty acid synthases (FASs) are giant multienzymes catalyzing all steps of the biosynthesis of fatty acids from acetyl- and malonyl-CoA by iterative precursor extension. Two strikingly different architectures of FAS evolved in yeast (as well as in other fungi and some bacteria) and metazoans. Yeast-type FAS (yFAS) assembles into a barrel-shaped structure of more than 2 MDa molecular weight. Catalytic domains of yFAS are embedded in an extensive scaffolding matrix and arranged around two enclosed reaction chambers. Metazoan FAS (mFAS) is a 540 kDa X-shaped dimer, with lateral reaction clefts, minimal scaffolding and pronounced conformational variability. All naturally occurring yFAS are strictly specialized for the production of saturated fatty acids. The yFAS architecture is not used for the biosynthesis of any other secondary metabolite. On the contrary, mFAS is related at the domain organization level to major classes of polyketide synthases (PKSs). PKSs produce a variety of complex and potent secondary metabolites; they either act iteratively (iPKS), or are linked via directed substrate transfer into modular assembly lines (modPKSs). Here, we review the architectures of yFAS, mFAS, and iPKSs. We rationalize the evolution of the yFAS assembly, and provide examples for re-engineering of yFAS. Recent studies have provided novel insights into the organization of iPKS. A hybrid crystallographic model of a mycocerosic acid synthase-like Pks5 yielded a comprehensive visualization of the organization and dynamics of fully-reducing iPKS. Deconstruction experiments, structural and functional studies of specialized enzymatic domains, such as the product template (PT) and the starter-unit acyltransferase (SAT) domain have revealed functional principles of non-reducing iterative PKS (NR-PKSs). Most recently, a six-domain loading region of an NR-PKS has been visualized at high-resolution together with cryo-EM studies of a trapped loading intermediate. Altogether, these data reveal the related, yet divergent architectures of mFAS, iPKS and also modPKSs. The new insights highlight extensive dynamics, and conformational coupling as key features of mFAS and iPKS and are an important step towards collection of a comprehensive series of snapshots of PKS action.
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Affiliation(s)
- Dominik A Herbst
- Department Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland.
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Abdel-Hameed ME, Bertrand RL, Donald LJ, Sorensen JL. Lichen ketosynthase domains are not responsible for inoperative polyketide synthases in Ascomycota hosts. Biochem Biophys Res Commun 2018; 503:1228-1234. [DOI: 10.1016/j.bbrc.2018.07.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 07/06/2018] [Indexed: 02/06/2023]
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7
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Bollu LR, Ren J, Blessing AM, Katreddy RR, Gao G, Xu L, Wang J, Su F, Weihua Z. Involvement of de novo synthesized palmitate and mitochondrial EGFR in EGF induced mitochondrial fusion of cancer cells. Cell Cycle 2015; 13:2415-30. [PMID: 25483192 DOI: 10.4161/cc.29338] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Increased expressions of fatty acid synthase (FASN) and epidermal growth factor receptor (EGFR) are common in cancer cells. De novo synthesis of palmitate by FASN is critical for the survival of cancer cells via mechanisms independent of its role as an energy substrate. Besides the plasma membrane and the nucleus, EGFR can also localize at the mitochondria; however, signals that can activate mitochondrial EGFR (mtEGFR) and the functions of mtEGFR of cancer cells remain unknown. The present study characterizes mtEGFR in the mitochondria of cancer cells (prostate and breast) and reveals that mtEGFR can promote mitochondrial fusion through increasing the protein levels of fusion proteins PHB2 and OPA1. Activation of plasma membranous EGFR (pmEGFR) stimulates the de novo synthesis of palmitate through activation of FASN and ATP-citrate lyase (ACLy). In vitro kinase assay with isolated mitochondria shows that palmitate can activate mtEGFR. Inhibition of FASN blocks the mtEGFR phosphorylation and palmitoylation induced by EGF. Mutational studies show that the cysteine 797 is important for mtEGFR activation and palmitoylation. Inhibition of FASN can block EGF induced mitochondrial fusion and increased the sensitivity of prostate cancer cells to EGFR tyrosine kinase inhibitor. In conclusion, these results suggest that mtEGFR can be activated by pmEGFR through de novo synthesized palmitate to promote mitochondrial fusion and survival of cancer cells. This mechanism may serve as a novel target to improve EGFR-based cancer therapy.
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Affiliation(s)
- Lakshmi Reddy Bollu
- a Department of Biology and Biochemistry; College of Natural Sciences and Mathematics; University of Houston; Houston, TX USA
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8
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3-oxoacyl-ACP reductase from Schistosoma japonicum: integrated in silico-in vitro strategy for discovering antischistosomal lead compounds. PLoS One 2013; 8:e64984. [PMID: 23762275 PMCID: PMC3676400 DOI: 10.1371/journal.pone.0064984] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 04/18/2013] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Schistosomiasis is a disease caused by parasitic worms and more than 200 million people are infected worldwide. The emergence of resistance to the most commonly used drug, praziquantel (PZQ), makes the development of novel drugs an urgent task. 3-oxoacyl-ACP reductase (OAR), a key enzyme involved in the fatty acid synthesis pathway, has been identified as a potential drug target against many pathogenic organisms. However, no research on Schistosoma japonicum OAR (SjOAR) has been reported. The characterization of the SjOAR protein will provide new strategies for screening antischistosomal drugs that target SjOAR. METHODOLOGY/PRINCIPAL FINDINGS After cloning the SjOAR gene, recombinant SjOAR protein was purified and assayed for enzymatic activity. The tertiary structure of SjOAR was obtained by homology modeling and 27 inhibitor candidates were identified from 14,400 compounds through molecular docking based on the structure. All of these compounds were confirmed to be able to bind to the SjOAR protein by BIAcore analysis. Two compounds exhibited strong antischistosomal activity and inhibitory effects on the enzymatic activity of SjOAR. In contrast, these two compounds showed relatively low toxicity towards host cells. CONCLUSIONS/SIGNIFICANCE The work presented here shows the feasibility of isolation of new antischistosomal compounds using a combination of virtual screening and experimental validation. Based on this strategy, we successfully identified 2 compounds that target SjOAR with strong antischistosomal activity but relatively low cytotoxicity to host cells.
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9
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Xu W, Qiao K, Tang Y. Structural analysis of protein-protein interactions in type I polyketide synthases. Crit Rev Biochem Mol Biol 2012; 48:98-122. [PMID: 23249187 DOI: 10.3109/10409238.2012.745476] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Polyketide synthases (PKSs) are responsible for synthesizing a myriad of natural products with agricultural, medicinal relevance. The PKSs consist of multiple functional domains of which each can catalyze a specified chemical reaction leading to the synthesis of polyketides. Biochemical studies showed that protein-substrate and protein-protein interactions play crucial roles in these complex regio-/stereo-selective biochemical processes. Recent developments on X-ray crystallography and protein NMR techniques have allowed us to understand the biosynthetic mechanism of these enzymes from their structures. These structural studies have facilitated the elucidation of the sequence-function relationship of PKSs and will ultimately contribute to the prediction of product structure. This review will focus on the current knowledge of type I PKS structures and the protein-protein interactions in this system.
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Affiliation(s)
- Wei Xu
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, USA
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10
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Inhibitors of fatty acid synthesis in prokaryotes and eukaryotes as anti-infective, anticancer and anti-obesity drugs. Future Med Chem 2012; 4:1113-51. [PMID: 22709254 DOI: 10.4155/fmc.12.62] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
There is a large range of diseases, such diabetes and cancer, which are connected to abnormal fatty acid metabolism in human cells. Therefore, inhibitors of human fatty acid synthase have great potential to manage or treat these diseases. In prokaryotes, fatty acid synthesis is important for signaling, as well as providing starting materials for the synthesis of phospholipids, which are required for the formation of the cell membrane. Recently, there has been renewed interest in the development of new molecules that target bacterial fatty acid synthases for the treatment of bacterial diseases. In this review, we look at the differences and similarities between fatty acid synthesis in humans and bacteria and highlight various small molecules that have been shown to inhibit either the mammalian or bacterial fatty acid synthase or both.
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12
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Jensen-Urstad APL, Semenkovich CF. Fatty acid synthase and liver triglyceride metabolism: housekeeper or messenger? Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:747-53. [PMID: 22009142 DOI: 10.1016/j.bbalip.2011.09.017] [Citation(s) in RCA: 243] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 09/26/2011] [Accepted: 09/27/2011] [Indexed: 01/14/2023]
Abstract
Fatty acid synthase (FAS) catalyzes the de novo synthesis of fatty acids. In the liver, FAS has long been categorized as a housekeeping protein, producing fat for storage of energy when nutrients are present in excess. Most previous studies of FAS regulation have focused on the control of gene expression. However, recent findings suggest that hepatic FAS may also be involved in signaling processes that include activation of peroxisome proliferator-activated receptor α (PPARα). Moreover, reports of rapid alterations in FAS activity as well as findings of post-translational modifications of the FAS protein support the notion that dynamic events in addition to transcription impact FAS regulation. These results indicate that FAS enzyme activity can impact liver physiology through signaling as well as energy storage and that its regulation may be complex. This article is part of a Special Issue entitled Triglyceride Metabolism and Disease.
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Affiliation(s)
- Anne P L Jensen-Urstad
- Division of Endocrinology, Metabolism & Lipid Research, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
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13
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Zhao WH, Gao LF, Gao W, Yuan YS, Gao CC, Cao LG, Hu ZZ, Guo JQ, Zhang YX. Weight-reducing effect of Acer truncatum Bunge may be related to the inhibition of fatty acid synthase. Nat Prod Res 2011; 25:422-31. [PMID: 21328136 DOI: 10.1080/14786419.2010.488625] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In order to study the anti-obesity ability and inhibition towards fatty acid synthase (FAS) of the extract, a 70% ethanol extract of Acer truncatum Bunge (AT) leaves was further extracted with ethyl acetate. FAS is a very significant lipogenic enzyme, participating in energy metabolism in vivo; it has also been observed that FAS inhibitors might be potent anti-obesity agents. Experimental results on animals showed that the extract significantly reduced food intake and adipose, and effectively controlled weight evolution. Lipogenesis inhibition might be regarded as one of the reasons for the weight control and adipose reduction by AT. The extract was further isolated using a series of column chromatography that yielded 10 known compounds. 1,2,3,4,6-Penta-O-galloyl-β-D-glucose was found to be one of the major active constituents in the extract of AT.
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Affiliation(s)
- Wen-Hua Zhao
- School of Chemical Biology and Pharmaceutical Sciences, Capital Medical University, Beijing 100069, China.
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14
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Abstract
In all organisms, fatty acid synthesis is achieved in variations of a common cyclic reaction pathway by stepwise, iterative elongation of precursors with two-carbon extender units. In bacteria, all individual reaction steps are carried out by monofunctional dissociated enzymes, whereas in eukaryotes the fatty acid synthases (FASs) have evolved into large multifunctional enzymes that integrate the whole process of fatty acid synthesis. During the last few years, important advances in understanding the structural and functional organization of eukaryotic FASs have been made through a combination of biochemical, electron microscopic and X-ray crystallographic approaches. They have revealed the strikingly different architectures of the two distinct types of eukaryotic FASs, the fungal and the animal enzyme system. Fungal FAS is a 2·6 MDa α₆β₆ heterododecamer with a barrel shape enclosing two large chambers, each containing three sets of active sites separated by a central wheel-like structure. It represents a highly specialized micro-compartment strictly optimized for the production of saturated fatty acids. In contrast, the animal FAS is a 540 kDa X-shaped homodimer with two lateral reaction clefts characterized by a modular domain architecture and large extent of conformational flexibility that appears to contribute to catalytic efficiency.
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15
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Meier JL, Burkart MD. The chemical biology of modular biosynthetic enzymes. Chem Soc Rev 2009; 38:2012-45. [DOI: 10.1039/b805115c] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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16
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Abstract
This chapter describes structural and associated enzymological studies of polyketide synthases, including isolated single domains and multidomain fragments. The sequence-structure-function relationship of polyketide biosynthesis, compared with homologous fatty acid synthesis, is discussed in detail. Structural enzymology sheds light on sequence and structural motifs that are important for the precise timing, substrate recognition, enzyme catalysis, and protein-protein interactions leading to the extraordinary structural diversity of naturally occurring polyketides.
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Karmodiya K, Modak R, Sahoo N, Sajad S, Surolia N. Deciphering the key residues in Plasmodium falciparum beta-ketoacyl acyl carrier protein reductase responsible for interactions with Plasmodium falciparum acyl carrier protein. FEBS J 2008; 275:4756-66. [PMID: 18721141 DOI: 10.1111/j.1742-4658.2008.06608.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The type II fatty acid synthase (FAS) pathway of Plasmodium falciparum is a validated unique target for developing novel antimalarials, due to its intrinsic differences from the typeI pathway operating in humans. beta-Ketoacyl acyl carrier protein (ACP) reductase (FabG) performs the NADPH-dependent reduction of beta-ketoacyl-ACP to beta-hydroxyacyl-ACP, the first reductive step in the elongation cycle of fatty acid biosynthesis. In this article, we report intensive studies on the direct interactions of Plasmodium FabG and Plasmodium ACP in solution, in the presence and absence of its cofactor, NADPH, by monitoring the change in intrinsic fluorescence of P.falciparum FabG (PfFabG) and by surface plasmon resonance. To address the issue of the importance of the residues involved in strong, specific and stoichiometric binding of PfFabG to P.falciparum ACP (PfACP), we mutated Arg187, Arg190 and Arg230 of PfFabG. The activities of the mutants were assessed using both an ACP-dependent and an ACP-independent assay. The affinities of all the PfFabG mutants for acetoacetyl-ACP (the physiological substrate) were reduced to different extents as compared to wild-type PfFabG, but were equally active in biochemical assays with the substrate analog acetoacetyl-CoA. Kinetic analysis and studies of direct binding between PfFabG and PfACP confirmed the identification of Arg187 and Arg230 as critical residues for the PfFabG-PfACP interactions. Our studies thus reveal the significance of the positively charged/hydrophobic patch located adjacent to the active site cavities of PfFabG for interactions with PfACP.
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Affiliation(s)
- Krishanpal Karmodiya
- Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
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Zhao WH, Zhao CY, Gao LF, Feng FF, Gao W, Chen ZL, Zhang F, Cao LG, Bi XY, Chen Y, Zhu QY, Zhang YX. The novel inhibitory effect of Pangdahai on fatty acid synthase. IUBMB Life 2008; 60:185-94. [DOI: 10.1002/iub.28] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Pasta S, Witkowski A, Joshi AK, Smith S. Catalytic Residues Are Shared between Two Pseudosubunits of the Dehydratase Domain of the Animal Fatty Acid Synthase. ACTA ACUST UNITED AC 2007; 14:1377-85. [DOI: 10.1016/j.chembiol.2007.11.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2007] [Revised: 10/31/2007] [Accepted: 11/05/2007] [Indexed: 10/22/2022]
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Abstract
This review chronicles the synergistic growth of the fields of fatty acid and polyketide synthesis over the last century. In both animal fatty acid synthases and modular polyketide synthases, similar catalytic elements are covalently linked in the same order in megasynthases. Whereas in fatty acid synthases the basic elements of the design remain immutable, guaranteeing the faithful production of saturated fatty acids, in the modular polyketide synthases, the potential of the basic design has been exploited to the full for the elaboration of a wide range of secondary metabolites of extraordinary structural diversity.
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Affiliation(s)
- Stuart Smith
- Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, California 94609, USA.
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De Lay NR, Cronan JE. In vivo functional analyses of the type II acyl carrier proteins of fatty acid biosynthesis. J Biol Chem 2007; 282:20319-28. [PMID: 17522044 DOI: 10.1074/jbc.m703789200] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Acyl carrier protein (ACP) is a key component of the fatty acid synthesis pathways of both type I and type II synthesis systems. A large number of structure-function studies of various type II ACPs have been reported, but all are in vitro studies that assayed function or interaction of mutant ACPs with various enzymes of fatty acid synthesis or transfer. Hence in these studies functional properties of various mutant ACPs were assayed with only a subset of the many ACP-interacting proteins, which may not give an accurate overall view of the function of these proteins in vivo. This is especially so because Escherichia coli ACP has been reported to interact with several proteins that have no known roles in lipid metabolism. We therefore tested a large number of mutant derivatives of E. coli ACP carrying single amino acid substitutions for their abilities to restore growth to an E. coli strain carrying a temperature-sensitive mutation in acpP, the gene that encodes ACP. Many of these mutant proteins had previously been tested in vitro thus providing data for comparison with our results. We found that several mutant ACPs containing substitutions of ACP residues reported previously to be required for ACP function in vitro support normal growth of the acpP mutant strain. However, several mutant proteins reported to be severely defective in vitro failed to support growth of the acpP strain in vivo (or supported only weak growth). A collection of ACPs from diverse bacteria and from three eukaryotic organelles was also tested. All of the bacterial ACPs tested restored growth to the E. coli acpP mutant strain except those from two related bacteria, Enterococcus faecalis and Lactococcus lactis. Only one of the three eukaryotic organellar ACPs allowed growth. Strikingly the ACP is that of the apicoplast of Plasmodium falciparum (the protozoan that causes malaria). The fact that an ACP from a such diverse organism can replace AcpP function in E. coli suggests that some of the protein-protein interactions detected for AcpP may be not be essential for growth of E. coli.
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Affiliation(s)
- Nicholas R De Lay
- Department of Microbiology, University of Illinois at Urbana-Champaign, 601 S. Goodwin Avenue, Urbana, IL 61801, USA
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22
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López M, Lelliott CJ, Vidal-Puig A. Hypothalamic fatty acid metabolism: a housekeeping pathway that regulates food intake. Bioessays 2007; 29:248-61. [PMID: 17295284 DOI: 10.1002/bies.20539] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The hypothalamus is a specialized area in the brain that integrates the control of energy homeostasis. More than 70 years ago, it was proposed that the central nervous system sensed circulating levels of metabolites such as glucose, lipids and amino acids and modified feeding according to the levels of those molecules. This led to the formulation of the Glucostatic, Lipostatic and Aminostatic Hypotheses. It has taken almost that much time to demonstrate that circulating long-chain fatty acids act as signals of nutrient surplus in the hypothalamus. Moreover, pharmacological and/or genetic inhibition of fatty acid synthase, AMP-activated protein kinase and carnitine palmitoyltransferase 1 results in profound decrease in feeding and body weight in rodents. The molecular mechanism behind these actions depends on changes in the cellular pool of malonyl-CoA and fatty acyl-CoAs. Current evidence also suggests that this pathway may play a major role in the physiological regulation of feeding, by integrating hormonal and nutrient-derived signals in the hypothalamus. Here, we summarize what is known about hypothalamic fatty acid metabolism and feeding control and provide future directions for research. Understanding these molecular mechanisms could provide new targets for the treatment of obesity and related disorders.
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Affiliation(s)
- Miguel López
- Department of Clinical Biochemistry, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK.
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23
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Ma SM, Tang Y. Biochemical characterization of the minimal polyketide synthase domains in the lovastatin nonaketide synthase LovB. FEBS J 2007; 274:2854-64. [PMID: 17466016 DOI: 10.1111/j.1742-4658.2007.05818.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The biosynthesis of lovastatin in Aspergillus terreus requires two megasynthases. The lovastatin nonaketide synthase, LovB, synthesizes the intermediate dihydromonacolin L using nine malonyl-coenzyme A molecules, and is a reducing, iterative type I polyketide synthase. The iterative type I polyketide synthase is mechanistically different from bacterial type I polyketide synthases and animal fatty acid synthases. We have cloned the minimal polyketide synthase domains of LovB as standalone proteins and assayed their activities and substrate specificities. The didomain proteins ketosynthase-malonyl-coenzyme A:acyl carrier protein acyltransferase (KS-MAT) and acyl carrier protein-condensation (ACP-CON) domain were expressed solubly in Escherichia coli. The monodomains MAT, ACP and CON were also obtained as soluble proteins. The MAT domain can be readily labeled by [1,2-(14)C]malonyl-coenzyme A and can transfer the acyl group to both the cognate LovB ACP and heterologous ACPs from bacterial type I and type II polyketide synthases. Using the LovB ACP-CON didomain as an acyl acceptor, LovB MAT transferred malonyl and acetyl groups with k(cat)/K(m) values of 0.62 min(-1).mum(-1) and 0.032 min(-1).mum(-1), respectively. The LovB MAT domain was able to substitute the Streptomyces coelicolor FabD in supporting product turnover in a bacterial type II minimal polyketide synthase assay. The activity of the KS domain was assayed independently using a KS-MAT (S656A) mutant in which the MAT domain was inactivated. The KS domain displayed no activity towards acetyl groups, but was able to recognize malonyl groups in the absence of cerulenin. The relevance of these finding to the priming mechanism of fungal polyketide synthase is discussed.
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Affiliation(s)
- Suzanne M Ma
- Department of Chemical and Biomolecular Engineering, University of California-Los Angeles, 420 Westwood Plaza, Los Angeles, CA 90095, USA
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24
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Mercer AC, Burkart MD. The ubiquitous carrier protein--a window to metabolite biosynthesis. Nat Prod Rep 2007; 24:750-73. [PMID: 17653358 DOI: 10.1039/b603921a] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nature has developed a remarkable strategy to isolate metabolites from the milieu of the cell for chemical modification through the use of carrier proteins. Common to both primary and secondary metabolic pathways, acyl-carrier proteins constitute a conserved protein architecture which mediate the biosynthesis of a variety of metabolic products. Analogies have been made between the carrier protein and solid phase resin for chemical synthesis, as both entities provide a mechanism to separate compounds of interest from complex mixtures for selective chemical modification. However, there is significantly more to the carrier protein than an attachment point. In this review, we aim to systematically characterize the role of carrier proteins in various metabolic pathways and outline their utility in biosynthesis and biotechnology; 185 references are cited.
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Affiliation(s)
- Andrew C Mercer
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0358, USA
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25
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Karmodiya K, Surolia N. Analyses of co-operative transitions in Plasmodium falciparum beta-ketoacyl acyl carrier protein reductase upon co-factor and acyl carrier protein binding. FEBS J 2006; 273:4093-103. [PMID: 16934037 DOI: 10.1111/j.1742-4658.2006.05412.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The type II fatty acid synthase pathway of Plasmodium falciparum is a validated unique target for developing novel antimalarials because of its intrinsic differences from the type I pathway operating in humans. beta-Ketoacyl-acyl carrier protein reductase is the only enzyme of this pathway that has no isoforms and thus selective inhibitors can be developed for this player of the pathway. We report here intensive studies on the direct interactions of Plasmodiumbeta-ketoacyl-acyl carrier protein reductase with its cofactor, NADPH, acyl carrier protein, acetoacetyl-coenzyme A and other ligands in solution, by monitoring the intrinsic fluorescence (lambdamax 334 nM) of the protein as a result of its lone tryptophan, as well as the fluorescence of NADPH (lambdamax 450 nM) upon binding to the enzyme. Binding of the reduced cofactor makes the enzyme catalytically efficient, as it increases the binding affinity of the substrate, acetoacetyl-coenzyme A, by 16-fold. The binding affinity of acyl carrier protein to the enzyme also increases by approximately threefold upon NADPH binding. Plasmodiumbeta-ketoacyl-acyl carrier protein reductase exhibits negative, homotropic co-operative binding for NADPH, which is enhanced in the presence of acyl carrier protein. Acyl carrier protein increases the accessibility of NADPH to beta-ketoacyl-acyl carrier protein reductase, as evident from the increase in the accessibility of the tryptophan of beta-ketoacyl-acyl carrier protein reductase to acrylamide, from 81 to 98%. In the presence of NADP+, the reaction proceeds in the reverse direction (Ka=23.17 microM-1). These findings provide impetus for exploring the influence of ligands on the structure-activity relationship of Plasmodiumbeta-ketoacyl-acyl carrier protein reductase.
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Affiliation(s)
- Krishanpal Karmodiya
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
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26
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Austin MB, Saito T, Bowman ME, Haydock S, Kato A, Moore BS, Kay RR, Noel JP. Biosynthesis of Dictyostelium discoideum differentiation-inducing factor by a hybrid type I fatty acid-type III polyketide synthase. Nat Chem Biol 2006; 2:494-502. [PMID: 16906151 PMCID: PMC2864586 DOI: 10.1038/nchembio811] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2006] [Accepted: 07/13/2006] [Indexed: 11/08/2022]
Abstract
Differentiation-inducing factors (DIFs) are well known to modulate formation of distinct communal cell types from identical Dictyostelium discoideum amoebas, but DIF biosynthesis remains obscure. We report complimentary in vivo and in vitro experiments identifying one of two approximately 3,000-residue D. discoideum proteins, termed 'steely', as responsible for biosynthesis of the DIF acylphloroglucinol scaffold. Steely proteins possess six catalytic domains homologous to metazoan type I fatty acid synthases (FASs) but feature an iterative type III polyketide synthase (PKS) in place of the expected FAS C-terminal thioesterase used to off load fatty acid products. This new domain arrangement likely facilitates covalent transfer of steely N-terminal acyl products directly to the C-terminal type III PKS active sites, which catalyze both iterative polyketide extension and cyclization. The crystal structure of a steely C-terminal domain confirms conservation of the homodimeric type III PKS fold. These findings suggest new bioengineering strategies for expanding the scope of fatty acid and polyketide biosynthesis.
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Affiliation(s)
- Michael B Austin
- Howard Hughes Medical Institute, Jack H. Skirball Center for Chemical Biology and Proteomics, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
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27
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Hicks LM, Balibar CJ, Walsh CT, Kelleher NL, Hillson NJ. Probing intra- versus interchain kinetic preferences of L-Thr acylation on dimeric VibF with mass spectrometry. Biophys J 2006; 91:2609-19. [PMID: 16815901 PMCID: PMC1562378 DOI: 10.1529/biophysj.106.084848] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We present a method to probe intra- and interchain activities within dimeric nonribosomal peptide synthetases. Utilizing domain inactivation and analytical mass mutants in conjunction with rapid-quench, mass spectrometry, and a probabilistic kinetic model, we have elucidated the pre-steady-state intra- and interchain rates and the corresponding flux of the acylation of L-Thr onto VibF. Although the intra rate is significantly faster than the inter rate, the data are most consistent with an even flux of covalent substrate loading where neither pathway dominates. These pre-steady-state results confirm previous steady-state in vitro mutant complementation studies of VibF. Extension of this methodology to other dimeric nonribosomal peptide synthetases, and to the related fatty acid and polyketide synthases, will further our biophysical understanding of their acyl-intermediate-processing pathways.
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Affiliation(s)
- Leslie M Hicks
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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29
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Abstract
Mammalian fatty acid synthase (FAS) is a homodimeric, multifunctional polypeptide which comprises two full sets of catalytic subunits that carry out fatty acid synthesis. A recently published X-ray structure of FAS reveals, for the first time, the organization of all active sites involved in acyl chain elongation and provides a structural framework for interpretation of extensive functional studies. Further analysis with techniques capable of providing information about single molecule conformations will eventually provide a more complete understanding of FAS.
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Affiliation(s)
- Francisco J Asturias
- Department of Cell Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
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30
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Abstract
Two recent papers in Science reported the X-ray structures of the large, organizationally distinct animal and fungal fatty acid synthases at 5 A. These new structural insights have unexpected implications for enzyme function for the other "iterative" and "assembly line" megasynthases.
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Affiliation(s)
- Craig A Townsend
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA
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31
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Abstract
The homodimeric mammalian fatty acid synthase is one of the most complex cellular multienzymes, in that each 270-kilodalton polypeptide chain carries all seven functional domains required for fatty acid synthesis. We have calculated a 4.5 angstrom-resolution x-ray crystallographic map of porcine fatty acid synthase, highly homologous to the human multienzyme, and placed homologous template structures of all individual catalytic domains responsible for the cyclic elongation of fatty acid chains into the electron density. The positioning of domains reveals the complex architecture of the multienzyme forming an intertwined dimer with two lateral semicircular reaction chambers, each containing a full set of catalytic domains required for fatty acid elongation. Large distances between active sites and conformational differences between the reaction chambers demonstrate that mobility of the acyl carrier protein and general flexibility of the multienzyme must accompany handover of the reaction intermediates during the reaction cycle.
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Affiliation(s)
- Timm Maier
- Institute of Molecular Biology and Biophysics, Department of Biology, Swiss Federal Institute of Technology (ETH Zurich), 8093 Zurich, Switzerland
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32
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Affiliation(s)
- Stuart Smith
- Children's Hospital Oakland Research Institute, Oakland, CA 94609, USA.
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33
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Bhaumik P, Koski MK, Glumoff T, Hiltunen JK, Wierenga RK. Structural biology of the thioester-dependent degradation and synthesis of fatty acids. Curr Opin Struct Biol 2005; 15:621-8. [PMID: 16263264 DOI: 10.1016/j.sbi.2005.10.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Revised: 07/14/2005] [Accepted: 10/21/2005] [Indexed: 12/30/2022]
Abstract
The fatty acid degradation and synthesis pathways consist of the same four chemical transformations. These transformations are facilitated by conjugating the fatty acid, via a thioester bond, to coenzyme A or acyl carrier protein in, respectively, the degradation and synthesis pathways. These pathways are compartmentalized in the peroxisomes, mitochondria and cytosol of eukaryotic cells. Current structural knowledge of the enzymes comprising these pathways shows that the approximately 130 entries in the RCSB Protein Data Bank can be grouped into seven superfamilies. Multifunctional enzymes are important in both pathways.
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Affiliation(s)
- Prasenjit Bhaumik
- Biocenter Oulu and Department of Biochemistry, University of Oulu, Linnanmaa, PO Box 3000, FIN-90014 Oulu, Finland
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34
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Abstract
On page 1667 of this issue, Stuart Smith and colleagues [1] demonstrate that the animal fatty acid synthase is a head-to-head dimer rather than the head-to-tail dimer depicted in textbooks. This has important ramifications for the mechanisms of other multifunctional enzymes such as polyketide synthases [2].
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Affiliation(s)
- John E Cronan
- Department of Microbiology, University of Illinois, Urbana, 81801, USA
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35
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Karmodiya K, Srivastav RK, Surolia N. Production and purification of refolded recombinant Plasmodium falciparum β-ketoacyl-ACP reductase from inclusion bodies. Protein Expr Purif 2005; 42:131-6. [PMID: 15939298 DOI: 10.1016/j.pep.2005.02.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2005] [Revised: 02/11/2005] [Accepted: 02/11/2005] [Indexed: 11/21/2022]
Abstract
A recombinant form of Plasmodium falciparum beta-ketoacyl-ACP reductase (PfFabG) was overexpressed in Escherichia coli BL-21 codon plus (DE3). The resulting insoluble inclusion bodies were separated from cellular debris by extensive washing with buffer containing 0.05% Tween 20 and solubilized by homogenization with 8 M urea. Attempts to refold PfFabG from solubilized inclusion bodies employing Rotofor (separation based on different pIs of proteins in a mixture) followed by Ni(2+) or cation exchange chromatography were not successful either by bringing down the urea concentration instantaneously, stepwise, or by dialysis. Denatured PfFabG was therefore initially purified by cation exchange chromatography and was then correctly refolded at a final concentration of 100-200 microg/ml in a 20 mM Na-acetate buffer, pH 5.3, with 300 mM NaCl, 10% glycerol, and 0.05% Tween 20. The protein was found to be properly folded only in the presence of the cofactor NADPH and salt at a concentration 300 mM by drop dilution method at 2-8 degrees C for 12 h. The purified final product was >98% pure by denaturing gel electrophoresis. The purified protein was biologically active in a standard enzymatic assay using acetoacetyl-CoA as a substrate. The enzyme was found to be stable up to fourth day of purification and glycerol was found to stabilize enzyme activity for several weeks, during storage. This effort paves the way for elucidation of the structure-function correlations for PfFabG as well as exploration of the enzyme for developing inhibitors against it for combating malaria.
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Affiliation(s)
- Krishanpal Karmodiya
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
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36
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Asturias FJ, Chadick JZ, Cheung IK, Stark H, Witkowski A, Joshi AK, Smith S. Structure and molecular organization of mammalian fatty acid synthase. Nat Struct Mol Biol 2005; 12:225-32. [PMID: 15711565 DOI: 10.1038/nsmb899] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2004] [Accepted: 01/19/2005] [Indexed: 11/09/2022]
Abstract
De novo synthesis of fatty acids in the cytosol of animal cells is carried out by the multifunctional, homodimeric fatty acid synthase (FAS). Cryo-EM analysis of single FAS particles imaged under conditions that limit conformational variability, combined with gold labeling of the N termini and structural analysis of the FAS monomers, reveals two coiled monomers in an overlapping arrangement. Comparison of dimeric FAS structures related to different steps in the fatty acid synthesis process indicates that only limited local rearrangements are required for catalytic interaction among different functional domains. Monomer coiling probably contributes to FAS efficiency and provides a structural explanation for the reported activity of a FAS monomer dimerized to a catalytically inactive partner. The new FAS structure provides a new paradigm for understanding the architecture of FAS and the related modular polyketide synthases.
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Affiliation(s)
- Francisco J Asturias
- Department of Cell Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
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