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Ong KH, Hsieh YY, Sun DP, Huang SKH, Tian YF, Chou CL, Shiue YL, Joseph K, Chang IW. Underexpression of Carbamoyl Phosphate Synthetase I as Independent Unfavorable Prognostic Factor in Intrahepatic Cholangiocarcinoma: A Potential Theranostic Biomarker. Diagnostics (Basel) 2023; 13:2296. [PMID: 37443694 DOI: 10.3390/diagnostics13132296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 06/21/2023] [Accepted: 07/03/2023] [Indexed: 07/15/2023] Open
Abstract
Intrahepatic cholangiocarcinoma (IHCC) is the second most common malignant neoplasm of the liver. In spite of the increasing incidence worldwide, it is relatively rare in Western countries. IHCC is relatively common in Eastern and Southeastern Asia. Patients with IHCC are usually diagnosed at an advanced stage, therefore, the clinical outcome is dismal. Dysregulation of urea cycle metabolic enzyme expression is found in different types of cancers. Nevertheless, a comprehensive evaluation of genes related to the urea cycle (i.e., GO:0000050) has not been conducted in IHCC. By performing a comparative analysis of gene expression profiles, we specifically examined genes associated with the urea cycle (GO:0000050) in a publicly accessible transcriptomic dataset (GSE26566). Interestingly, CPS1 was identified as the second most prominently down-regulated gene in this context. Tumor tissues of 182 IHCC patients who underwent curative-intent hepatectomy were enrolled. The expression level of CPS1 protein in our IHCC cohort was assessed by immunohistochemical study. Subsequent to that, statistical analyses were carried out to examine the expression of CPS1 in relation to various clinicopathological factors, as well as to assess its impact on survival outcomes. We noticed that lower immunoreactivity of CPS1 in IHCC was associated with tumor progression (pT status) with statistical significance (p = 0.003). CPS1 underexpression was not only negatively correlated to overall survival (OS), disease-free survival (DFS), local recurrence-free survival (LRFS) and metastasis-free survival (MeFS) in univariate analysis but also an independent prognosticator to forecast poorer clinical outcome for all prognostic indices (OS, DFS, LRFS and MeFs) in patients with IHCC (all p ≤ 0.001). These results support that CPS1 may play a crucial role in IHCC oncogenesis and tumor progression and serve as a novel prognostic factor and a potential diagnostic and theranostic biomarker.
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Affiliation(s)
- Khaa Hoo Ong
- Division of Gastroenterology & General Surgery, Department of Surgery, Chi Mei Medical Center, Tainan 710, Taiwan
- Department of Medical Technology, Chung Hwa University of Medical Technology, Tainan 717, Taiwan
- Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung 804, Taiwan
| | - Yao-Yu Hsieh
- Division of Hematology and Oncology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei 235, Taiwan
- Division of Hematology and Oncology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan
| | - Ding-Ping Sun
- Division of Gastroenterology & General Surgery, Department of Surgery, Chi Mei Medical Center, Tainan 710, Taiwan
| | - Steven Kuan-Hua Huang
- Division of Urology, Department of Surgery, Chi Mei Medical Center, Tainan 710, Taiwan
- Department of Medical Science Industries, College of Health Sciences, Chang Jung Christian University, Tainan 711, Taiwan
| | - Yu-Feng Tian
- Division of Colon and Rectal Surgery, Department of Surgery, Chi Mei Medical Center, Tainan 710, Taiwan
| | - Chia-Ling Chou
- Department of Medical Technology, Chung Hwa University of Medical Technology, Tainan 717, Taiwan
- Division of Colon and Rectal Surgery, Department of Surgery, Chi Mei Medical Center, Tainan 710, Taiwan
| | - Yow-Ling Shiue
- Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung 804, Taiwan
- Institute of Precision Medicine, National Sun Yat-sen University, Kaohsiung 804, Taiwan
| | - Keva Joseph
- St. Jude Hospital, Vieux Fort LC12 201, Saint Lucia
| | - I-Wei Chang
- Department of Pathology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan
- Department of Clinical Pathology, Wan Fang Hospital, Taipei Medical University, Taipei 116, Taiwan
- Department of Pathology, Taipei Medical University Hospital, Taipei 110, Taiwan
- Department of Pathology, Shuang Ho Hospital, Taipei Medical University, Taipei 235, Taiwan
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Unraveling the therapeutic potential of carbamoyl phosphate synthetase 1 (CPS1) in human disease. Bioorg Chem 2022; 130:106253. [DOI: 10.1016/j.bioorg.2022.106253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/23/2022] [Accepted: 11/01/2022] [Indexed: 11/07/2022]
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White LJ, Sutton G, Shechonge A, Day JJ, Dasmahapatra KK, Pownall ME. Adaptation of the carbamoyl-phosphate synthetase enzyme in an extremophile fish. ROYAL SOCIETY OPEN SCIENCE 2020; 7:201200. [PMID: 33204476 PMCID: PMC7657897 DOI: 10.1098/rsos.201200] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 09/21/2020] [Indexed: 05/03/2023]
Abstract
Tetrapods and fish have adapted distinct carbamoyl-phosphate synthase (CPS) enzymes to initiate the ornithine urea cycle during the detoxification of nitrogenous wastes. We report evidence that in the ureotelic subgenus of extremophile fish Oreochromis Alcolapia, CPS III has undergone convergent evolution and adapted its substrate affinity to ammonia, which is typical of terrestrial vertebrate CPS I. Unusually, unlike in other vertebrates, the expression of CPS III in Alcolapia is localized to the skeletal muscle and is activated in the myogenic lineage during early embryonic development with expression remaining in mature fish. We propose that adaptation in Alcolapia included both convergent evolution of CPS function to that of terrestrial vertebrates, as well as changes in development mechanisms redirecting CPS III gene expression to the skeletal muscle.
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Affiliation(s)
- Lewis J. White
- Biology Department, University of York, York YO10 5DD, UK
- Author for correspondence: Lewis J. White e-mail:
| | - Gemma Sutton
- Biology Department, University of York, York YO10 5DD, UK
| | - Asilatu Shechonge
- Tanzania Fisheries Research Institute, PO BOX 98, Kyela, Mbeya, Tanzania
| | - Julia J. Day
- Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
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Shi D, Caldovic L, Tuchman M. Sources and Fates of Carbamyl Phosphate: A Labile Energy-Rich Molecule with Multiple Facets. BIOLOGY 2018; 7:biology7020034. [PMID: 29895729 PMCID: PMC6022934 DOI: 10.3390/biology7020034] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 05/25/2018] [Accepted: 06/07/2018] [Indexed: 11/16/2022]
Abstract
Carbamyl phosphate (CP) is well-known as an essential intermediate of pyrimidine and arginine/urea biosynthesis. Chemically, CP can be easily synthesized from dihydrogen phosphate and cyanate. Enzymatically, CP can be synthesized using three different classes of enzymes: (1) ATP-grasp fold protein based carbamyl phosphate synthetase (CPS); (2) Amino-acid kinase fold carbamate kinase (CK)-like CPS (anabolic CK or aCK); and (3) Catabolic transcarbamylase. The first class of CPS can be further divided into three different types of CPS as CPS I, CPS II, and CPS III depending on the usage of ammonium or glutamine as its nitrogen source, and whether N-acetyl-glutamate is its essential co-factor. CP can donate its carbamyl group to the amino nitrogen of many important molecules including the most well-known ornithine and aspartate in the arginine/urea and pyrimidine biosynthetic pathways. CP can also donate its carbamyl group to the hydroxyl oxygen of a variety of molecules, particularly in many antibiotic biosynthetic pathways. Transfer of the carbamyl group to the nitrogen group is catalyzed by the anabolic transcarbamylase using a direct attack mechanism, while transfer of the carbamyl group to the oxygen group is catalyzed by a different class of enzymes, CmcH/NodU CTase, using a different mechanism involving a three-step reaction, decomposition of CP to carbamate and phosphate, transfer of the carbamyl group from carbamate to ATP to form carbamyladenylate and pyrophosphate, and transfer of the carbamyl group from carbamyladenylate to the oxygen group of the substrate. CP is also involved in transferring its phosphate group to ADP to generate ATP in the fermentation of many microorganisms. The reaction is catalyzed by carbamate kinase, which may be termed as catabolic CK (cCK) in order to distinguish it from CP generating CK. CP is a thermally labile molecule, easily decomposed into phosphate and cyanate, or phosphate and carbamate depending on the pH of the solution, or the presence of enzyme. Biological systems have developed several mechanisms including channeling between enzymes, increased affinity of CP to enzymes, and keeping CP in a specific conformation to protect CP from decomposition. CP is highly important for our health as both a lack of, or decreased, CP production and CP accumulation results in many disease conditions.
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Affiliation(s)
- Dashuang Shi
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA.
- Department of Genomics and Precision Medicine, The George Washington University, Washington, DC 20010, USA.
| | - Ljubica Caldovic
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA.
- Department of Genomics and Precision Medicine, The George Washington University, Washington, DC 20010, USA.
| | - Mendel Tuchman
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA.
- Department of Genomics and Precision Medicine, The George Washington University, Washington, DC 20010, USA.
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Hu L, Diez-Fernandez C, Rüfenacht V, Hismi BÖ, Ünal Ö, Soyucen E, Çoker M, Bayraktar BT, Gunduz M, Kiykim E, Olgac A, Pérez-Tur J, Rubio V, Häberle J. Recurrence of carbamoyl phosphate synthetase 1 (CPS1) deficiency in Turkish patients: characterization of a founder mutation by use of recombinant CPS1 from insect cells expression. Mol Genet Metab 2014; 113:267-73. [PMID: 25410056 DOI: 10.1016/j.ymgme.2014.09.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 09/30/2014] [Accepted: 09/30/2014] [Indexed: 12/26/2022]
Abstract
Carbamoyl phosphate synthetase 1 (CPS1) deficiency due to CPS1 mutations is a rare autosomal-recessive urea cycle disorder causing hyperammonemia that can lead to death or severe neurological impairment. CPS1 catalyzes carbamoyl phosphate formation from ammonia, bicarbonate and two molecules of ATP, and requires the allosteric activator N-acetyl-L-glutamate. Clinical mutations occur in the entire CPS1 coding region, but mainly in single families, with little recurrence. We characterized here the only currently known recurrent CPS1 mutation, p.Val1013del, found in eleven unrelated patients of Turkish descent using recombinant His-tagged wild type or mutant CPS1 expressed in baculovirus/insect cell system. The global CPS1 reaction and the ATPase and ATP synthesis partial reactions that reflect, respectively, the bicarbonate and the carbamate phosphorylation steps, were assayed. We found that CPS1 wild type and V1013del mutant showed comparable expression levels and purity but the mutant CPS1 exhibited no significant residual activities. In the CPS1 structural model, V1013 belongs to a highly hydrophobic β-strand at the middle of the central β-sheet of the A subdomain of the carbamate phosphorylation domain and is close to the predicted carbamate tunnel that links both phosphorylation sites. Haplotype studies suggested that p.Val1013del is a founder mutation. In conclusion, the mutation p.V1013del inactivates CPS1 but does not render the enzyme grossly unstable or insoluble. Recurrence of this particular mutation in Turkish patients is likely due to a founder effect, which is consistent with the frequent consanguinity observed in the affected population.
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Affiliation(s)
- Liyan Hu
- Division of Metabolism, University Children's Hospital, 8032 Zurich, Switzerland; Children's Research Center, 8032 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, Switzerland
| | - Carmen Diez-Fernandez
- Division of Metabolism, University Children's Hospital, 8032 Zurich, Switzerland; Children's Research Center, 8032 Zurich, Switzerland; Instituto de Biomedicina de Valencia (IBV-CSIC), Valencia, Spain
| | - Véronique Rüfenacht
- Division of Metabolism, University Children's Hospital, 8032 Zurich, Switzerland; Children's Research Center, 8032 Zurich, Switzerland
| | - Burcu Öztürk Hismi
- Department of Pediatric Metabolic Diseases, Ihsan Dogramaci Children's Hospital, Hacettepe University, Ankara, Turkey; Gaziantep Children's Hospital, Gaziantep, Turkey
| | - Özlem Ünal
- Department of Pediatric Metabolic Diseases, Ihsan Dogramaci Children's Hospital, Hacettepe University, Ankara, Turkey; Erzurum Regional Training and Research Hospital, Erzurum, Turkey
| | - Erdogan Soyucen
- Department of Pediatric Metabolic Disease, Medical School, Akdeniz University, Antalya, Turkey
| | - Mahmut Çoker
- Department of Pediatric Metabolic Disease, Medical School, Ege University, Bornova, Izmir, Turkey
| | - Bilge Tanyeri Bayraktar
- Division of Neonatology, Department of Pediatrics, Bezmialem Vakif University, Istanbul, Turkey
| | - Mehmet Gunduz
- Ankara Cocuk Sagligi ve Hastaliklari, Cocuk Beslenme & Metabolizma Unitesi, Diskapi, Ankara, Turkey
| | - Ertugrul Kiykim
- Department of Pediatric Metabolic Diseases, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, Turkey
| | - Asburce Olgac
- Division of Metabolism and Nutrition, Gazi University Hospital, Ankara, Turkey
| | - Jordi Pérez-Tur
- Instituto de Biomedicina de Valencia (IBV-CSIC), Valencia, Spain; Centro de Investigación Biomédica en Red para Enfermedades Neurodegenerativas (CIBERNED-ISCIII), Valencia, Spain; Instituto de Investigación Sanitaria La Fe, Valencia, Spain
| | - Vicente Rubio
- Instituto de Biomedicina de Valencia (IBV-CSIC), Valencia, Spain; Group 739, Centro de Investigación Biomédica en Red para Enfermedades Raras (CIBERER-ISCIII), Valencia, Spain
| | - Johannes Häberle
- Division of Metabolism, University Children's Hospital, 8032 Zurich, Switzerland; Children's Research Center, 8032 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, Switzerland.
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Popa E, Perera N, Kibédi-Szabó CZ, Guy-Evans H, Evans DR, Purcarea C. The smallest active carbamoyl phosphate synthetase was identified in the human gut archaeon Methanobrevibacter smithii. J Mol Microbiol Biotechnol 2012; 22:287-99. [PMID: 23107800 PMCID: PMC6158779 DOI: 10.1159/000342520] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The genome of the major intestinal archaeon Methanobrevibacter smithii contains a complex gene system coding for carbamoyl phosphate synthetase (CPSase) composed of both full-length and reduced-size synthetase subunits. These ammonia-metabolizing enzymes could play a key role in controlling ammonia assimilation in M. smithii, affecting the metabolism of gut bacterial microbiota, with an impact on host obesity. In this study, we isolated and characterized the small (41 kDa) CPSase homolog from M. smithii. The gene was cloned and overexpressed in Escherichia coli, and the recombinant enzyme was purified in one step. Chemical cross-linking and size exclusion chromatography indicated a homodimeric/tetrameric structure, in accordance with a dimer-based CPSase activity and reaction mechanism. This small enzyme, MS-s, synthesized carbamoyl phosphate from ATP, bicarbonate, and ammonia and catalyzed the same ATP-dependent partial reactions observed for full-length CPSases. Steady-state kinetics revealed a high apparent affinity for ATP and ammonia. Sequence comparisons, molecular modeling, and kinetic studies suggest that this enzyme corresponds to one of the two synthetase domains of the full-length CPSase that catalyze the ATP-dependent phosphorylations involved in the three-step synthesis of carbamoyl phosphate. This protein represents the smallest naturally occurring active CPSase characterized thus far. The small M. smithii CPSase appears to be specialized for carbamoyl phosphate metabolism in methanogens.
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Affiliation(s)
- Elena Popa
- Department of Microbiology, Institute of Biology Bucharest, Romanian Academy, Bucharest 060031, Romania
| | - Nirosha Perera
- Department of Chemistry, Eastern Michigan University, Ypsilanti, MI 48197, USA
| | - Csaba Z. Kibédi-Szabó
- Department of Microbiology, Institute of Biology Bucharest, Romanian Academy, Bucharest 060031, Romania
| | - Hedeel Guy-Evans
- Department of Chemistry, Eastern Michigan University, Ypsilanti, MI 48197, USA
| | - David R. Evans
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Cristina Purcarea
- Department of Microbiology, Institute of Biology Bucharest, Romanian Academy, Bucharest 060031, Romania
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Häberle J, Shchelochkov OA, Wang J, Katsonis P, Hall L, Reiss S, Eeds A, Willis A, Yadav M, Summar S, Lichtarge O, Rubio V, Wong LJ, Summar M. Molecular defects in human carbamoy phosphate synthetase I: mutational spectrum, diagnostic and protein structure considerations. Hum Mutat 2011; 32:579-89. [PMID: 21120950 DOI: 10.1002/humu.21406] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 10/27/2010] [Indexed: 11/09/2022]
Abstract
Deficiency of carbamoyl phosphate synthetase I (CPSI) results in hyperammonemia ranging from neonatally lethal to environmentally induced adult-onset disease. Over 24 years, analysis of tissue and DNA samples from 205 unrelated individuals diagnosed with CPSI deficiency (CPSID) detected 192 unique CPS1 gene changes, of which 130 are reported here for the first time. Pooled with the already reported mutations, they constitute a total of 222 changes, including 136 missense, 15 nonsense, 50 changes of other types resulting in enzyme truncation, and 21 other changes causing in-frame alterations. Only ∼10% of the mutations recur in unrelated families, predominantly affecting CpG dinucleotides, further complicating the diagnosis because of the "private" nature of such mutations. Missense changes are unevenly distributed along the gene, highlighting the existence of CPSI regions having greater functional importance than other regions. We exploit the crystal structure of the CPSI allosteric domain to rationalize the effects of mutations affecting it. Comparative modeling is used to create a structural model for the remainder of the enzyme. Missense changes are found to directly correlate, respectively, with the one-residue evolutionary importance and inversely correlate with solvent accessibility of the mutated residue. This is the first large-scale report of CPS1 mutations spanning a wide variety of molecular defects highlighting important regions in this protein.
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Affiliation(s)
- Johannes Häberle
- University Children's Hospital Zurich, Division of Metabolism, Zurich, Switzerland.
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Martínez AI, Pérez-Arellano I, Pekkala S, Barcelona B, Cervera J. Genetic, structural and biochemical basis of carbamoyl phosphate synthetase 1 deficiency. Mol Genet Metab 2010; 101:311-23. [PMID: 20800523 DOI: 10.1016/j.ymgme.2010.08.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 08/02/2010] [Accepted: 08/02/2010] [Indexed: 01/28/2023]
Abstract
Carbamoyl phosphate synthetase 1 (CPS1) plays a paramount role in liver ureagenesis since it catalyzes the first and rate-limiting step of the urea cycle, the major pathway for nitrogen disposal in humans. CPS1 deficiency (CPS1D) is an autosomal recessive inborn error which leads to hyperammonemia due to mutations in the CPS1 gene, or is caused secondarily by lack of its allosteric activator NAG. Proteolytic, immunological and structural data indicate that human CPS1 resembles Escherichia coli CPS in structure, and a 3D model of CPS1 has been presented for elucidating the pathogenic role of missense mutations. Recent availability of CPS1 expression systems also can provide valuable tools for structure-function analysis and pathogenicity-testing of mutations in CPS1. In this paper, we provide a comprehensive compilation of clinical CPS1 mutations, and discuss how structural knowledge of CPS enzymes in combination with in vitro analyses can be a useful tool for diagnosis of CPS1D.
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Affiliation(s)
- Ana Isabel Martínez
- Molecular Recognition Laboratory, Centro de Investigación Príncipe Felipe (CIPF) Valencia, Spain
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Pekkala S, Martínez AI, Barcelona B, Yefimenko I, Finckh U, Rubio V, Cervera J. Understanding carbamoyl-phosphate synthetase I (CPS1) deficiency by using expression studies and structure-based analysis. Hum Mutat 2010; 31:801-8. [PMID: 20578160 DOI: 10.1002/humu.21272] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Carbamoyl-phosphate synthetase I (CPS1) deficiency (CPS1D), a recessively inherited urea cycle error due to CPS1 gene mutations, causes life-threatening hyperammonemia. The disease-causing potential of missense mutations in CPS1 deficiency can be ascertained with the recombinant CPS1 expression and purification system reported here, which uses baculovirus and insect cells. We study with this system the effects of nine clinical mutations and one polymorphism on CPS1 solubility, stability, activity, and kinetic parameters for NAG. Five of the mutations (p.T471N, p.Q678P, p.P774L, p.R1453Q, and p.R1453W) are first reported here, in three severe CPS1D patients. p.P774L, p.R1453Q, and p.R1453W inactivate CPS1, p.T471N and p.Y1491H greatly decrease the apparent affinity for NAG, p.Q678P hampers correct enzyme folding, and p.S123F, p.H337R, and p.P1411L modestly decrease activity. p.G1376S is confirmed a trivial polymorphism. The effects of the C-terminal domain mutations are rationalized in the light of this domain crystal structure, including the NAG site structure [Pekkala et al. Biochem J 424:211-220]. The agreement of clinical observations and in vitro findings, and the possibility to identify CPS1D patients who might benefit from specific treatment with NAG analogues because they exhibit reduced affinity for NAG highlight the value of this novel CPS1 expression/purification system.
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Affiliation(s)
- Satu Pekkala
- Centro de Investigación Príncipe Felipe (CIPF), Valencia, Spain
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Structural insight on the control of urea synthesis: identification of the binding site for N-acetyl-L-glutamate, the essential allosteric activator of mitochondrial carbamoyl phosphate synthetase. Biochem J 2009; 424:211-20. [PMID: 19754428 DOI: 10.1042/bj20090888] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
NAG (N-acetyl-L-glutamate), the essential allosteric activator of the first urea cycle enzyme, CPSI (carbamoyl phosphate synthetase I), is a key regulator of this crucial cycle for ammonia detoxification in animals (including humans). Automated cavity searching and flexible docking have allowed identification of the NAG site in the crystal structure of human CPSI C-terminal domain. The site, a pocket lined by invariant residues and located between the central beta-sheet and two alpha-helices, opens at the beta-sheet C-edge and is roofed by a three-residue lid. It can tightly accommodate one extended NAG molecule having the delta-COO- at the pocket entry, the alpha-COO- and acetamido groups tightly hydrogen bonded to the pocket, and the terminal methyl of the acetamido substituent surrounded by hydrophobic residues. This binding mode is supported by the observation of reduced NAG affinity upon mutation of NAG-interacting residues of CPSI (recombinantly expressed using baculovirus/insect cells); by the fine-mapping of the N-chloroacetyl-L-glutamate photoaffinity labelling site of CPSI; and by previously established structure-activity relationships for NAG analogues. The location of the NAG site is identical to that of the weak bacterial CPS activator IMP (inosine monophosphate) in Escherichia coli CPS, indicating a common origin for these sites and excluding any relatedness to the binding site of the other bacterial CPS activator, ornithine. Our findings open the way to the identification of CPSI deficiency patients carrying NAG site mutations, and to the possibility of tailoring the activator to fit a given NAG site mutation, as exemplified here with N-acetyl-L(+/-)-beta-phenylglutamate for the W1410K CPSI mutation.
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Popa E, Rusu A, Zamfir M, Dumitru L, Purcarea C. An Ammonia-Metabolizing Enzyme from the Human Archaeon Methanobrevibacter SmithiiMight Represent a Missing Link in the Evolution of Carbamoyl Phosphate Synthetases. BIOTECHNOL BIOTEC EQ 2009. [DOI: 10.1080/13102818.2009.10818480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Kothe M, Purcarea C, Guy HI, Evans DR, Powers-Lee SG. Direct demonstration of carbamoyl phosphate formation on the C-terminal domain of carbamoyl phosphate synthetase. Protein Sci 2004; 14:37-44. [PMID: 15576558 PMCID: PMC2253338 DOI: 10.1110/ps.041041305] [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: 10/26/2022]
Abstract
Carbamoyl phosphate synthetase synchronizes the utilization of two ATP molecules at duplicated ATP-grasp folds to catalyze carbamoyl phosphate formation. To define the dedicated functional role played by each of the two ATP sites, we have carried out pulse/labeling studies using the synthetases from Aquifex aeolicus and Methanococcus jannaschii, hyperthermophilic organisms that encode the two ATP-grasp folds on separate subunits. These studies allowed us to differentially label each active site with [gamma-(32)P]ATP and determine the fate of the labeled gamma-phosphate in the synthetase reaction. Our results provide the first direct demonstration that enzyme-catalyzed transfer of phosphate from ATP to carbamate occurs on the more C-terminal of the two ATP-grasp folds. These findings rule out one mechanism proposed for carbamoyl phosphate synthetase, where one ATP acts as a molecular switch, and provide additional support for a sequential reaction mechanism where the gamma-phosphate groups of both ATP molecules are transferred to reactants. CP synthesis by subunit C in our single turnover pulse/chase assays did not require subunit N, but subunit N was required for detectable CP synthesis in the traditional continuous assay. These findings suggest that cross-talk between domain N and C is required for product release from subunit C.
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Affiliation(s)
- Michael Kothe
- Department of Biology, Northeastern University, Boston, MA 02115, USA
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Giard JC, Laplace JM, Rincé A, Pichereau V, Benachour A, Leboeuf C, Flahaut S, Auffray Y, Hartke A. The stress proteome of Enterococcus faecalis. Electrophoresis 2001; 22:2947-54. [PMID: 11565789 DOI: 10.1002/1522-2683(200108)22:14<2947::aid-elps2947>3.0.co;2-k] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Enterococcus faecalis is a resident bacterium of the intestinal tract of humans and animals. This bacterium can be responsible for serious diseases and is one of the largest causes of hospital-based infections. This hardy organism resists many kinds of stresses and is used as a major indicator of the hygienic quality of food, milk, and drinking water. On the other side, enterococci seem to have beneficial role in the development of cheese aroma and are added in certain starter cultures. Since ten years, our laboratory has used the two-dimensional electrophoresis (2-DE) technique to study the response of E. faecalis to physical or chemical stresses as well as to glucose and total starvation. Twenty-seven protein spots on 2-D gels have been identified by N-terminal sequencing or Western blotting which make up the first proteome database of this species. The proteins were classified in four different groups according to their function and their regulation. The first group comprises well-characterized proteins with known protective functions towards stresses. The second group contains enzymes of catabolic pathways. Their implication in stress resistance seems not obvious. A third group are proteins induced in glucose-starved cells belonging to the CcpA regulon. Induction of these enzymes under starvation may serve to increase the scavenging capacity of the cells for nutrients or may be important to mobilize endogenous energetic reserves. Lastly, nine N-terminal amino acid sequences or open reading frames (ORF) showed no homologies with sequences in databases. A comprehensive description of stress proteins of E. faecalis and analysis of their patterns of expression under different environmental conditions would greatly increase our understanding of the molecular mechanisms underlying the extraordinary capacity of this bacterium to survive under hostile conditions.
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Affiliation(s)
- J C Giard
- Laboratoire de Microbiologie de l'Environnement, Université de Caen, France.
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Ramón-Maiques S, Marina A, Uriarte M, Fita I, Rubio V. The 1.5 A resolution crystal structure of the carbamate kinase-like carbamoyl phosphate synthetase from the hyperthermophilic Archaeon pyrococcus furiosus, bound to ADP, confirms that this thermostable enzyme is a carbamate kinase, and provides insight into substrate binding and stability in carbamate kinases. J Mol Biol 2000; 299:463-76. [PMID: 10860751 DOI: 10.1006/jmbi.2000.3779] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Carbamoyl phosphate (CP), an essential precursor of arginine and the pyrimidine bases, is synthesized by CP synthetase (CPS) in three steps. The last step, the phosphorylation of carbamate, is also catalyzed by carbamate kinase (CK), an enzyme used by microorganisms to produce ATP from ADP and CP. Although the recently determined structures of CPS and CK show no obvious mutual similarities, a CK-like CPS reported in hyperthermophilic archaea was postulated to be a missing link in the evolution of CP biosynthesis. The 1.5 A resolution structure of this enzyme from Pyrococcus furiosus shows both a subunit topology and a homodimeric molecular organization, with a 16-stranded open beta-sheet core surrounded by alpha-helices, similar to those in CK. However, the pyrococcal enzyme exhibits many solvent-accessible ion-pairs, an extensive, strongly hydrophobic, intersubunit surface, and presents a bound ADP molecule, which does not dissociate at 22 degrees C from the enzyme. The ADP nucleotide is sequestered in a ridge formed over the C-edge of the core sheet, at the bottom of a large cavity, with the purine ring enclosed in a pocket specific for adenine. Overall, the enzyme structure is ill-suited for catalyzing the characteristic three-step reaction of CPS and supports the view that the CK-like CPS is in fact a highly thermostable and very slow (at 37 degrees C) CK that, in the extreme environment of P. furiosus, may have the new function of making, rather than using, CP. The thermostability of the enzyme may result from the extension of the hydrophobic intersubunit contacts and from the large number of exposed ion-pairs, some of which form ion-pair networks across several secondary structure elements in each enzyme subunit. The structure provides the first information on substrate binding and catalysis in CKs, and suggests that the slow rate at 37 degrees C is possibly a consequence of slow product dissociation.
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Affiliation(s)
- S Ramón-Maiques
- Consejo Superior de Investigaciones Científicas (IBV-CSIC), Instituto de Biomedicina de Valencia, C/Jaime Roig 11, Valencia, 46010, Spain
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Guy HI, Bouvier A, Evans DR. The smallest carbamoyl-phosphate synthetase. A single catalytic subdomain catalyzes all three partial reactions. J Biol Chem 1997; 272:29255-62. [PMID: 9361005 DOI: 10.1074/jbc.272.46.29255] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Escherichia coli carbamoyl-phosphate synthetase (CPSase) is comprised of a 40-kDa glutaminase (GLN) and a 120-kDa synthetase (CPS) subunit. The CPS subunit consists of two homologous domains, CPS.A and CPS.B, which catalyze the two different ATP-dependent partial reactions involved in carbamoyl phosphate synthesis. Sequence similarities and controlled proteolysis experiments suggest that the CPS subdomains consist, in turn, of three subdomains, designated A1, A2, A3 and B1, B2, B3 for CPS.A and CPS.B, respectively. Previous studies of individually cloned CPS.A and CPS. B from E. coli and mammalian CPSase have shown that homologous dimers of either of these "half-molecules" could catalyze all three reactions involved in ammonia-dependent carbamoyl phosphate synthesis. Four smaller recombinant proteins were made for this study as follows: 1) A1-A2 in which the A3 subdomain was deleted from CPS.A, 2) B1-B2 lacking subdomain B3 of CPS.B, 3) the A2 subdomain of CPS.A, and 4) the B2 subdomain of CPS.B. When associated with the GLN subunit, A1-A2 and B1-B2 had both glutamine- and ammonia-dependent CPSase activities comparable to the wild-type protein. In contrast, the 27-kDa A2 and B2 recombinant proteins, which represent only 17% of the mass of the parent protein, were unable to use glutamine as a nitrogen donor, but the ammonia-dependent activity was enhanced 14-16-fold. The hyperactivity suggests that A2 and B2 are the catalytic subdomains and that A1 and B1 are attenuation domains which suppress the intrinsically high activity and are required for the physical association with the GLN subunit.
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Affiliation(s)
- H I Guy
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
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Giard JC, Hartke A, Flahaut S, Boutibonnes P, Auffray Y. Glucose starvation response in Enterococcus faecalis JH2-2: survival and protein analysis. Res Microbiol 1997; 148:27-35. [PMID: 9404502 DOI: 10.1016/s0923-2508(97)81897-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We investigated the survival of Enterococcus faecalis following starvation provoked by energy source glucose exhaustion. Inhibition of protein synthesis by chloramphenicol before 3 h of starvation resulted in a dramatic decrease in viable bacteria. Antibiotic treatment of cells after 3 or 6 h of starvation had a progressively lesser influence on bacterial survival. During the first 24 h of deprivation, a total of 42 proteins were identified as glucose-starvation-inducible; 4 temporal classes of proteins (A, B, C and D) were defined in relation to their enhanced synthesis after glucose exhaustion. Our results show that proteins from the two early classes (A and B) seem to be the most important for long-term survival in E. faecalis. One protein of each of these classes was analysed at the molecular level. The N-terminal sequence of one of them, belonging to class A, showed strong homology with the N-terminal sequence of carbamate kinase from Streptococcus faecium. This enzyme could be implicated in the development of alternative metabolic pathways of energy production and could be compared to the Cst proteins of Escherichia coli.
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Affiliation(s)
- J C Giard
- Laboratoire de Microbiologie de l'Environnement, Université de Caen, Caen, France
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McCudden CR, Powers-Lee SG. Required allosteric effector site for N-acetylglutamate on carbamoyl-phosphate synthetase I. J Biol Chem 1996; 271:18285-94. [PMID: 8663466 DOI: 10.1074/jbc.271.30.18285] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Carbamoyl-phosphate synthetase I (CPSase I) catalyzes the entry and rate-limiting step in the urea cycle, the pathway by which mammals detoxify ammonia. One facet of CPSase I regulation is a requirement for N-acetylglutamate (AGA), which induces an active enzyme conformation and does not participate directly in the chemical reaction. We have utilized labeling with carbodiimide-activated [14C]AGA to identify peptides 120-127, 234-237, 625-630, and 1351-1356 as potentially being near the binding site for AGA. Identification of peptide 1351-1356 confirms the previous demonstration (Rodriquez-Aparicio, L. B., Guadalajara, A. M., and Rubio, V.(1989) Biochemistry 28, 3070-3074) that the C-terminal region is involved in binding AGA. Identification of peptides 120-127 and 234-237 constitutes the first evidence that the N-terminal region of the synthetase is involved in ligand binding. Since peptides 631-638 and 1327-1348 have been identified near the ATP site of CPSase I (Potter, M. D., and Powers-Lee, S. G.(1992) J. Biol. Chem. 267, 2023-2031), the present finding of involvement of peptides 625-630 and 1351-1356 at an "allosteric" activator site was unexpected. The idea that portions of the AGA effector site might be derived from an ancestral glutamine substrate site via a gene duplication and diversification event was considered.
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Affiliation(s)
- C R McCudden
- Department of Biology, Northeastern University, Boston, Massachusetts 02115, USA
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