1
|
Dhar YV, Asif MH. Genome and transcriptome-wide study of carbamoyltransferase genes in major fleshy fruits: A multi-omics study of evolution and functional significance. FRONTIERS IN PLANT SCIENCE 2022; 13:994159. [PMID: 36407603 PMCID: PMC9669488 DOI: 10.3389/fpls.2022.994159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Abstract
The carbamoyltransferase or aspartate carbamoyltransferase (ATCase)/ornithine carbamoyltransferase (OTCase) is an evolutionary conserved protein family, which contains two genes, ATCase and OTCase. The ATCase catalyzes the committed step in the synthesis of UMP from which all pyrimidine molecules are synthesized. The second member, OTCase, catalytically regulates the conversion of ornithine to citrulline. This study traces the evolution of the carbomoyltransferase genes in the plant kingdom and their role during fruit ripening in fleshy fruits. These genes are highly conserved throughout the plant kingdom and, except for melon and watermelon, do not show gene expansion in major fleshy fruits. In this study, 393 carbamoyltransferase genes were identified in the plant kingdom, including 30 fleshy fruit representatives. Their detailed phylogeny, evolutionary patterns with their expression during the process of fruit ripening, was analyzed. The ATcase and OTcase genes were conserved throughout the plant kingdom and exhibited lineage-specific signatures. The expression analysis of the ATcase and OTcase genes during fruit development and ripening in climacteric and non-climacteric fruits showed their involvement in fruit ripening irrespective of the type of fruits. No direct role in relation to ethylene-dependent or -independent ripening was identified; however, the co-expression network suggests their involvement in the various ripening processes.
Collapse
Affiliation(s)
- Yogeshwar V. Dhar
- CSIR-National Botanical Research Institute (CSIR-NBRI), Lucknow, India
- Academy of Scientific and Innovative Research to Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Mehar H. Asif
- CSIR-National Botanical Research Institute (CSIR-NBRI), Lucknow, India
- Academy of Scientific and Innovative Research to Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| |
Collapse
|
2
|
Pyrimidine Biosynthetic Enzyme CAD: Its Function, Regulation, and Diagnostic Potential. Int J Mol Sci 2021; 22:ijms221910253. [PMID: 34638594 PMCID: PMC8508918 DOI: 10.3390/ijms221910253] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 09/18/2021] [Accepted: 09/19/2021] [Indexed: 01/10/2023] Open
Abstract
CAD (Carbamoyl-phosphate synthetase 2, Aspartate transcarbamoylase, and Dihydroorotase) is a multifunctional protein that participates in the initial three speed-limiting steps of pyrimidine nucleotide synthesis. Over the past two decades, extensive investigations have been conducted to unmask CAD as a central player for the synthesis of nucleic acids, active intermediates, and cell membranes. Meanwhile, the important role of CAD in various physiopathological processes has also been emphasized. Deregulation of CAD-related pathways or CAD mutations cause cancer, neurological disorders, and inherited metabolic diseases. Here, we review the structure, function, and regulation of CAD in mammalian physiology as well as human diseases, and provide insights into the potential to target CAD in future clinical applications.
Collapse
|
3
|
Yao S, Nguyen TV, Rolfe A, Agrawal AA, Ke J, Peng S, Colombo F, Yu S, Bouchard P, Wu J, Huang KC, Bao X, Omoto K, Selvaraj A, Yu L, Ioannidis S, Vaillancourt FH, Zhu P, Larsen NA, Bolduc DM. Small Molecule Inhibition of CPS1 Activity through an Allosteric Pocket. Cell Chem Biol 2020; 27:259-268.e5. [PMID: 32017919 DOI: 10.1016/j.chembiol.2020.01.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 12/09/2019] [Accepted: 01/13/2020] [Indexed: 02/06/2023]
Abstract
Carbamoyl phosphate synthetase 1 (CPS1) catalyzes the first step in the ammonia-detoxifying urea cycle, converting ammonia to carbamoyl phosphate under physiologic conditions. In cancer, CPS1 overexpression supports pyrimidine synthesis to promote tumor growth in some cancer types, while in others CPS1 activity prevents the buildup of toxic levels of intratumoral ammonia to allow for sustained tumor growth. Targeted CPS1 inhibitors may, therefore, provide a therapeutic benefit for cancer patients with tumors overexpressing CPS1. Herein, we describe the discovery of small-molecule CPS1 inhibitors that bind to a previously unknown allosteric pocket to block ATP hydrolysis in the first step of carbamoyl phosphate synthesis. CPS1 inhibitors are active in cellular assays, blocking both urea synthesis and CPS1 support of the pyrimidine biosynthetic pathway, while having no activity against CPS2. These newly discovered CPS1 inhibitors are a first step toward providing researchers with valuable tools for probing CPS1 cancer biology.
Collapse
Affiliation(s)
- Shihua Yao
- H3 Biomedicine Inc., 300 Technology Square, Cambridge, MA 02139, USA
| | - Tuong-Vi Nguyen
- H3 Biomedicine Inc., 300 Technology Square, Cambridge, MA 02139, USA
| | - Alan Rolfe
- H3 Biomedicine Inc., 300 Technology Square, Cambridge, MA 02139, USA
| | - Anant A Agrawal
- H3 Biomedicine Inc., 300 Technology Square, Cambridge, MA 02139, USA
| | - Jiyuan Ke
- H3 Biomedicine Inc., 300 Technology Square, Cambridge, MA 02139, USA
| | - Shouyong Peng
- H3 Biomedicine Inc., 300 Technology Square, Cambridge, MA 02139, USA
| | - Federico Colombo
- H3 Biomedicine Inc., 300 Technology Square, Cambridge, MA 02139, USA
| | - Sean Yu
- RMI Laboratories LLC, 418 Industrial Drive, North Wales, PA 19454, USA
| | - Patricia Bouchard
- NMX Research and Solutions, Inc., 500 Cartier Boulevard W., Laval, Quebec H7V 5B7, Canada
| | - Jiayi Wu
- H3 Biomedicine Inc., 300 Technology Square, Cambridge, MA 02139, USA
| | - Kuan-Chun Huang
- H3 Biomedicine Inc., 300 Technology Square, Cambridge, MA 02139, USA
| | - Xingfeng Bao
- H3 Biomedicine Inc., 300 Technology Square, Cambridge, MA 02139, USA
| | - Kiyoyuki Omoto
- H3 Biomedicine Inc., 300 Technology Square, Cambridge, MA 02139, USA
| | - Anand Selvaraj
- H3 Biomedicine Inc., 300 Technology Square, Cambridge, MA 02139, USA
| | - Lihua Yu
- H3 Biomedicine Inc., 300 Technology Square, Cambridge, MA 02139, USA
| | | | | | - Ping Zhu
- H3 Biomedicine Inc., 300 Technology Square, Cambridge, MA 02139, USA
| | - Nicholas A Larsen
- H3 Biomedicine Inc., 300 Technology Square, Cambridge, MA 02139, USA
| | - David M Bolduc
- H3 Biomedicine Inc., 300 Technology Square, Cambridge, MA 02139, USA.
| |
Collapse
|
4
|
Lei Z, Wang B, Lu Z, Wang N, Tan H, Zheng J, Jia Z. New regulatory mechanism-based inhibitors of aspartate transcarbamoylase for potential anticancer drug development. FEBS J 2020; 287:3579-3599. [PMID: 31967710 DOI: 10.1111/febs.15220] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/06/2020] [Accepted: 01/17/2020] [Indexed: 11/27/2022]
Abstract
Aspartate transcarbamoylase (ATCase) is a key enzyme which regulates and catalyzes the second step of de novo pyrimidine synthesis in all organisms. Escherichia coli ATCase is a prototypic enzyme regulated by both product feedback and substrate cooperativity, whereas human ATCase is a potential anticancer target. Through structural and biochemical analyses, we revealed that R167/130's loop region in ATCase serves as a gatekeeper for the active site, playing a new and unappreciated regulatory role in the catalytic cycle of ATCase. Based on virtual compound screening simultaneously targeting the new regulatory region and active site of human ATCase, two compounds were identified to exhibit strong inhibition of ATCase activity, proliferation of multiple cancer cell lines, and growth of xenograft tumors. Our work has not only revealed a previously unknown regulatory region of ATCase that helps uncover the catalytic and regulatory mechanism of ATCase, but also successfully guided the identification of new ATCase inhibitors for anticancer drug development using a dual-targeting strategy. DATABASE: Structure data are available in Protein Data Bank under the accession numbers: 6KJ7 (G166P ecATCase), 6KJ8 (G166P ecATCase-holo), 6KJ9 (G128/130A ecATCase), and 6KJA (G128/130A ecATCase-holo).
Collapse
Affiliation(s)
- Zhen Lei
- College of Chemistry, Beijing Normal University, China
| | - Biying Wang
- College of Chemistry, Beijing Normal University, China
| | - Zhifang Lu
- College of Chemistry, Beijing Normal University, China
| | - Nan Wang
- College of Chemistry, Beijing Normal University, China.,Jiangsu Key Laboratory of Brain Disease Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, China
| | - Hongwei Tan
- College of Chemistry, Beijing Normal University, China
| | - Jimin Zheng
- College of Chemistry, Beijing Normal University, China
| | - Zongchao Jia
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Canada
| |
Collapse
|
5
|
Abstract
The CAD complex catalyzes the first four reactions of the pyrimidine biosynthetic pathway. CAD exhibits allosteric regulaton, both negative and positive, covalent regulation by phosphorylation, and metabolite channeling. In this issue of Structure, Moreno-Morcillo et al. (2017) show that the dihydroorotase domain plays a crucial role in the establishment of the quaternary structure of this complex.
Collapse
Affiliation(s)
- Guy Hervé
- IBPS/Université Pierre et Marie Curie, 75005 Paris, France.
| |
Collapse
|
6
|
Moreno-Morcillo M, Grande-García A, Ruiz-Ramos A, Del Caño-Ochoa F, Boskovic J, Ramón-Maiques S. Structural Insight into the Core of CAD, the Multifunctional Protein Leading De Novo Pyrimidine Biosynthesis. Structure 2017; 25:912-923.e5. [PMID: 28552578 DOI: 10.1016/j.str.2017.04.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/05/2017] [Accepted: 04/28/2017] [Indexed: 11/17/2022]
Abstract
CAD, the multifunctional protein initiating and controlling de novo biosynthesis of pyrimidines in animals, self-assembles into ∼1.5 MDa hexamers. The structures of the dihydroorotase (DHO) and aspartate transcarbamoylase (ATC) domains of human CAD have been previously determined, but we lack information on how these domains associate and interact with the rest of CAD forming a multienzymatic unit. Here, we prove that a construct covering human DHO and ATC oligomerizes as a dimer of trimers and that this arrangement is conserved in CAD-like from fungi, which holds an inactive DHO-like domain. The crystal structures of the ATC trimer and DHO-like dimer from the fungus Chaetomium thermophilum confirm the similarity with the human CAD homologs. These results demonstrate that, despite being inactive, the fungal DHO-like domain has a conserved structural function. We propose a model that sets the DHO and ATC complex as the central element in the architecture of CAD.
Collapse
Affiliation(s)
- María Moreno-Morcillo
- Structural Bases of Genome Integrity Group, Structural Biology and Biocomputing Programme, Spanish National Cancer Research Centre (CNIO), Melchor Fernández Almagro, 3, Madrid 28029, Spain
| | - Araceli Grande-García
- Structural Bases of Genome Integrity Group, Structural Biology and Biocomputing Programme, Spanish National Cancer Research Centre (CNIO), Melchor Fernández Almagro, 3, Madrid 28029, Spain
| | - Alba Ruiz-Ramos
- Structural Bases of Genome Integrity Group, Structural Biology and Biocomputing Programme, Spanish National Cancer Research Centre (CNIO), Melchor Fernández Almagro, 3, Madrid 28029, Spain
| | - Francisco Del Caño-Ochoa
- Structural Bases of Genome Integrity Group, Structural Biology and Biocomputing Programme, Spanish National Cancer Research Centre (CNIO), Melchor Fernández Almagro, 3, Madrid 28029, Spain
| | - Jasminka Boskovic
- Electron Microscopy Unit, Structural Biology and Biocomputing Programme, Spanish National Cancer Research Centre (CNIO), Melchor Fernández Almagro, 3, Madrid 28029, Spain
| | - Santiago Ramón-Maiques
- Structural Bases of Genome Integrity Group, Structural Biology and Biocomputing Programme, Spanish National Cancer Research Centre (CNIO), Melchor Fernández Almagro, 3, Madrid 28029, Spain; Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Nicolás Cabrera, 1, Madrid 28049, Spain.
| |
Collapse
|
7
|
Ruiz-Ramos A, Velázquez-Campoy A, Grande-García A, Moreno-Morcillo M, Ramón-Maiques S. Structure and Functional Characterization of Human Aspartate Transcarbamoylase, the Target of the Anti-tumoral Drug PALA. Structure 2016; 24:1081-94. [PMID: 27265852 DOI: 10.1016/j.str.2016.05.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 05/03/2016] [Accepted: 05/03/2016] [Indexed: 01/30/2023]
Abstract
CAD, the multienzymatic protein that initiates and controls de novo synthesis of pyrimidines in animals, associates through its aspartate transcarbamoylase (ATCase) domain into particles of 1.5 MDa. Despite numerous structures of prokaryotic ATCases, we lack structural information on the ATCase domain of CAD. Here, we report the structure and functional characterization of human ATCase, confirming the overall similarity with bacterial homologs. Unexpectedly, human ATCase exhibits cooperativity effects that reduce the affinity for the anti-tumoral drug PALA. Combining structural, mutagenic, and biochemical analysis, we identified key elements for the necessary regulation and transmission of conformational changes leading to cooperativity between subunits. Mutation of one of these elements, R2024, was recently found to cause the first non-lethal CAD deficit. We reproduced this mutation in human ATCase and measured its effect, demonstrating that this arginine is part of a molecular switch that regulates the equilibrium between low- and high-affinity states for the ligands.
Collapse
Affiliation(s)
- Alba Ruiz-Ramos
- Structural Bases of Genome Integrity Group, Structural Biology and Biocomputing Programme, Spanish National Cancer Research Centre (CNIO), Melchor Fdez. Almagro, 3, Madrid 28029, Spain
| | - Adrián Velázquez-Campoy
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Unit IQFR-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain; Department of Biochemistry and Molecular and Cell Biology, Universidad de Zaragoza, 50009 Zaragoza, Spain; Aragon Institute for Health Research (IIS Aragon), 50009 Zaragoza, Spain; Fundacion ARAID, Government of Aragon, 50018 Zaragoza, Spain
| | - Araceli Grande-García
- Structural Bases of Genome Integrity Group, Structural Biology and Biocomputing Programme, Spanish National Cancer Research Centre (CNIO), Melchor Fdez. Almagro, 3, Madrid 28029, Spain
| | - María Moreno-Morcillo
- Structural Bases of Genome Integrity Group, Structural Biology and Biocomputing Programme, Spanish National Cancer Research Centre (CNIO), Melchor Fdez. Almagro, 3, Madrid 28029, Spain
| | - Santiago Ramón-Maiques
- Structural Bases of Genome Integrity Group, Structural Biology and Biocomputing Programme, Spanish National Cancer Research Centre (CNIO), Melchor Fdez. Almagro, 3, Madrid 28029, Spain.
| |
Collapse
|
8
|
Hermansen RA, Mannakee BK, Knecht W, Liberles DA, Gutenkunst RN. Characterizing selective pressures on the pathway for de novo biosynthesis of pyrimidines in yeast. BMC Evol Biol 2015; 15:232. [PMID: 26511837 PMCID: PMC4625875 DOI: 10.1186/s12862-015-0515-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 10/20/2015] [Indexed: 12/05/2022] Open
Abstract
Background Selection on proteins is typically measured with the assumption that each protein acts independently. However, selection more likely acts at higher levels of biological organization, requiring an integrative view of protein function. Here, we built a kinetic model for de novo pyrimidine biosynthesis in the yeast Saccharomyces cerevisiae to relate pathway function to selective pressures on individual protein-encoding genes. Results Gene families across yeast were constructed for each member of the pathway and the ratio of nonsynonymous to synonymous nucleotide substitution rates (dN/dS) was estimated for each enzyme from S. cerevisiae and closely related species. We found a positive relationship between the influence that each enzyme has on pathway function and its selective constraint. Conclusions We expect this trend to be locally present for enzymes that have pathway control, but over longer evolutionary timescales we expect that mutation-selection balance may change the enzymes that have pathway control. Electronic supplementary material The online version of this article (doi:10.1186/s12862-015-0515-x) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Russell A Hermansen
- Department of Molecular Biology, University of Wyoming, Laramie, WY, 82071, USA. .,Department of Biology and Center for Computational Genetics and Genomics, Temple University, Philadelphia, PA, 19122, USA.
| | - Brian K Mannakee
- Division of Epidemiology and Biostatistics, Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, AZ, 85721, USA.
| | - Wolfgang Knecht
- Department of Biology and Lund Protein Production Platform, Lund University, 22362, Lund, Sweden.
| | - David A Liberles
- Department of Molecular Biology, University of Wyoming, Laramie, WY, 82071, USA. .,Department of Biology and Center for Computational Genetics and Genomics, Temple University, Philadelphia, PA, 19122, USA.
| | - Ryan N Gutenkunst
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, 85721, USA.
| |
Collapse
|
9
|
Shi D, Allewell NM, Tuchman M. From Genome to Structure and Back Again: A Family Portrait of the Transcarbamylases. Int J Mol Sci 2015; 16:18836-64. [PMID: 26274952 PMCID: PMC4581275 DOI: 10.3390/ijms160818836] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 07/29/2015] [Accepted: 07/30/2015] [Indexed: 11/18/2022] Open
Abstract
Enzymes in the transcarbamylase family catalyze the transfer of a carbamyl group from carbamyl phosphate (CP) to an amino group of a second substrate. The two best-characterized members, aspartate transcarbamylase (ATCase) and ornithine transcarbamylase (OTCase), are present in most organisms from bacteria to humans. Recently, structures of four new transcarbamylase members, N-acetyl-l-ornithine transcarbamylase (AOTCase), N-succinyl-l-ornithine transcarbamylase (SOTCase), ygeW encoded transcarbamylase (YTCase) and putrescine transcarbamylase (PTCase) have also been determined. Crystal structures of these enzymes have shown that they have a common overall fold with a trimer as their basic biological unit. The monomer structures share a common CP binding site in their N-terminal domain, but have different second substrate binding sites in their C-terminal domain. The discovery of three new transcarbamylases, l-2,3-diaminopropionate transcarbamylase (DPTCase), l-2,4-diaminobutyrate transcarbamylase (DBTCase) and ureidoglycine transcarbamylase (UGTCase), demonstrates that our knowledge and understanding of the spectrum of the transcarbamylase family is still incomplete. In this review, we summarize studies on the structures and function of transcarbamylases demonstrating how structural information helps to define biological function and how small structural differences govern enzyme specificity. Such information is important for correctly annotating transcarbamylase sequences in the genome databases and for identifying new members of the transcarbamylase family.
Collapse
Affiliation(s)
- Dashuang Shi
- Center for Genetic Medicine Research, Children's National Medical Center, the George Washington University, Washington, DC 20010, USA.
- Department of Integrative Systems Biology, Children's National Medical Center, the George Washington University, Washington, DC 20010, USA.
| | - Norma M Allewell
- Department of Cell Biology and Molecular Genetics, College of Computer, Mathematical, and Natural Sciences, University of Maryland, College Park, MD 20742, USA.
- Department of Chemistry and Biochemistry, College of Computer, Mathematical, and Natural Sciences, University of Maryland, College Park, MD 20742, USA.
| | - Mendel Tuchman
- Center for Genetic Medicine Research, Children's National Medical Center, the George Washington University, Washington, DC 20010, USA.
- Department of Integrative Systems Biology, Children's National Medical Center, the George Washington University, Washington, DC 20010, USA.
| |
Collapse
|
10
|
Brady BS, Hyman BC, Lovatt CJ. Regulation of CPSase, ACTase, and OCTase genes in Medicago truncatula: Implications for carbamoylphosphate synthesis and allocation to pyrimidine and arginine de novo biosynthesis. Gene 2010; 462:18-25. [PMID: 20451592 DOI: 10.1016/j.gene.2010.04.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Revised: 03/25/2010] [Accepted: 04/16/2010] [Indexed: 11/27/2022]
Abstract
In most prokaryotes and many eukaryotes, synthesis of carbamoylphosphate (CP) by carbamoylphosphate synthetase (CPSase; E.C. 6.3.5.5) and its allocation to either pyrimidine or arginine biosynthesis are highly controlled processes. Regulation at the transcriptional level occurs at either CPSase genes or the downstream genes encoding aspartate carbamoyltransferase (E.C. 2.1.3.2) or ornithine carbamoyltransferase (E.C. 2.1.3.3). Given the importance of pyrimidine and arginine biosynthesis, our lack of basic knowledge regarding genetic regulation of these processes in plants is a striking omission. Transcripts encoding two CPSase small subunits (MtCPSs1 and MtCPSs2), a single CPSase large subunit (MtCPSl), ACTase (MtPyrB), and OCTase (MtArgF) were characterized in the model legume Medicago truncatula. Quantitative real-time PCR data provided evidence (i) that the accumulation of all CPSase gene transcripts, as well as the MtPyrB transcript, was dramatically reduced following seedling incubation with uridine; (ii) exogenously supplied arginine down regulated only MtArgF; and (iii) mRNA levels of both CPSase small subunits, MtPyrB, and MtArgF were significantly increased after supplying plants with ornithine alone or in combination with uridine or arginine compared to plants treated with only uridine or arginine, respectively (P< or =0.05). A proposed novel, yet simple regulatory scheme employed by M. truncatula more closely resembles a prokaryotic control strategy than those used by other eukaryotes.
Collapse
Affiliation(s)
- Brian S Brady
- Department of Botany and Plant Sciences, University of California, Riverside, CA 92521, USA.
| | | | | |
Collapse
|
11
|
Kwapisz M, Wery M, Després D, Ghavi-Helm Y, Soutourina J, Thuriaux P, Lacroute F. Mutations of RNA polymerase II activate key genes of the nucleoside triphosphate biosynthetic pathways. EMBO J 2008; 27:2411-21. [PMID: 18716630 PMCID: PMC2525842 DOI: 10.1038/emboj.2008.165] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Accepted: 07/30/2008] [Indexed: 01/22/2023] Open
Abstract
The yeast URA2 gene, encoding the rate-limiting enzyme of UTP biosynthesis, is transcriptionally activated by UTP shortage. In contrast to other genes of the UTP pathway, this activation is not governed by the Ppr1 activator. Moreover, it is not due to an increased recruitment of RNA polymerase II at the URA2 promoter, but to its much more effective progression beyond the URA2 mRNA start site(s). Regulatory mutants constitutively expressing URA2 resulted from cis-acting deletions upstream of the transcription initiator region, or from amino-acid replacements altering the RNA polymerase II Switch 1 loop domain, such as rpb1-L1397S. These two mutation classes allowed RNA polymerase to progress downstream of the URA2 mRNA start site(s). rpb1-L1397S had similar effects on IMD2 (IMP dehydrogenase) and URA8 (CTP synthase), and thus specifically activated the rate-limiting steps of UTP, GTP and CTP biosynthesis. These data suggest that the Switch 1 loop of RNA polymerase II, located at the downstream end of the transcription bubble, may operate as a specific sensor of the nucleoside triphosphates available for transcription.
Collapse
Affiliation(s)
- Marta Kwapisz
- CEA, iBiTec-S, Service de Biologie Intégrative et Génétique Moléculaire, Gif-sur-Yvette, France
| | | | | | | | | | | | | |
Collapse
|
12
|
Balbaa M, Abdel-Megeed M, Diab T, Mansour H. Inhibition of mammalian aspartate transcarbamylase by quinazolinone derivatives. J Enzyme Inhib Med Chem 2008; 23:483-92. [PMID: 18665995 DOI: 10.1080/14756360701709474] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Quinazolinone derivatives have been studied as both in vitro and in vivo inhibitors of aspartate transcarbamylase (ATCase). In vitro treatment of mammalian ATCase with four compounds revealed that they inhibited enzyme activity and that 2-phenyl-1,3-4(H)benzothiazin-4-thione was the most potent one. This compound acts as a noncompetitive inhibitor towards both aspartate and carbamoyl phosphate. The values of the inhibition constant (K(i)) indicate that this compound exerts a potent inhibitory effect upon ATCase activity. Moreover, in vivo treatment with different doses of these derivatives showed also an inhibitory effect upon ATCase, the relative activity being decreased by 40%-58% with a 1 mg dose. These data support the inhibition of ATCase by quinazolinone derivatives as a new type of inhibitor for the enzyme.
Collapse
Affiliation(s)
- Mahmoud Balbaa
- Department of Biochemistry, Faculty of Science, Alexandria University, Alexandria, Egypt.
| | | | | | | |
Collapse
|
13
|
Yura K, Yamaguchi A, Go M. Coverage of whole proteome by structural genomics observed through protein homology modeling database. JOURNAL OF STRUCTURAL AND FUNCTIONAL GENOMICS 2006; 7:65-76. [PMID: 17146617 PMCID: PMC1769342 DOI: 10.1007/s10969-006-9010-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2006] [Accepted: 08/08/2006] [Indexed: 11/07/2022]
Abstract
We have been developing FAMSBASE, a protein homology-modeling database of whole ORFs predicted from genome sequences. The latest update of FAMSBASE ( http://daisy.nagahama-i-bio.ac.jp/Famsbase/ ), which is based on the protein three-dimensional (3D) structures released by November 2003, contains modeled 3D structures for 368,724 open reading frames (ORFs) derived from genomes of 276 species, namely 17 archaebacterial, 130 eubacterial, 18 eukaryotic and 111 phage genomes. Those 276 genomes are predicted to have 734,193 ORFs in total and the current FAMSBASE contains protein 3D structure of approximately 50% of the ORF products. However, cases that a modeled 3D structure covers the whole part of an ORF product are rare. When portion of an ORF with 3D structure is compared in three kingdoms of life, in archaebacteria and eubacteria, approximately 60% of the ORFs have modeled 3D structures covering almost the entire amino acid sequences, however, the percentage falls to about 30% in eukaryotes. When annual differences in the number of ORFs with modeled 3D structure are calculated, the fraction of modeled 3D structures of soluble protein for archaebacteria is increased by 5%, and that for eubacteria by 7% in the last 3 years. Assuming that this rate would be maintained and that determination of 3D structures for predicted disordered regions is unattainable, whole soluble protein model structures of prokaryotes without the putative disordered regions will be in hand within 15 years. For eukaryotic proteins, they will be in hand within 25 years. The 3D structures we will have at those times are not the 3D structure of the entire proteins encoded in single ORFs, but the 3D structures of separate structural domains. Measuring or predicting spatial arrangements of structural domains in an ORF will then be a coming issue of structural genomics.
Collapse
Affiliation(s)
- Kei Yura
- Quantum Bioinformatics Team, Center for Computational Science and Engineering, Japan Atomic Energy Agency, Kyoto 619-0215, Japan.
| | | | | |
Collapse
|