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Kovářová J, Moos M, Barrett MP, Horn D, Zíková A. The bloodstream form of Trypanosoma brucei displays non-canonical gluconeogenesis. PLoS Negl Trop Dis 2024; 18:e0012007. [PMID: 38394337 PMCID: PMC10917290 DOI: 10.1371/journal.pntd.0012007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 03/06/2024] [Accepted: 02/16/2024] [Indexed: 02/25/2024] Open
Abstract
Trypanosoma brucei is a causative agent of the Human and Animal African Trypanosomiases. The mammalian stage parasites infect various tissues and organs including the bloodstream, central nervous system, skin, adipose tissue and lungs. They rely on ATP produced in glycolysis, consuming large amounts of glucose, which is readily available in the mammalian host. In addition to glucose, glycerol can also be used as a source of carbon and ATP and as a substrate for gluconeogenesis. However, the physiological relevance of glycerol-fed gluconeogenesis for the mammalian-infective life cycle forms remains elusive. To demonstrate its (in)dispensability, first we must identify the enzyme(s) of the pathway. Loss of the canonical gluconeogenic enzyme, fructose-1,6-bisphosphatase, does not abolish the process hence at least one other enzyme must participate in gluconeogenesis in trypanosomes. Using a combination of CRISPR/Cas9 gene editing and RNA interference, we generated mutants for four enzymes potentially capable of contributing to gluconeogenesis: fructose-1,6-bisphoshatase, sedoheptulose-1,7-bisphosphatase, phosphofructokinase and transaldolase, alone or in various combinations. Metabolomic analyses revealed that flux through gluconeogenesis was maintained irrespective of which of these genes were lost. Our data render unlikely a previously hypothesised role of a reverse phosphofructokinase reaction in gluconeogenesis and preclude the participation of a novel biochemical pathway involving transaldolase in the process. The sustained metabolic flux in gluconeogenesis in our mutants, including a triple-null strain, indicates the presence of a unique enzyme participating in gluconeogenesis. Additionally, the data provide new insights into gluconeogenesis and the pentose phosphate pathway, and improve the current understanding of carbon metabolism of the mammalian-infective stages of T. brucei.
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Affiliation(s)
- Julie Kovářová
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic
| | - Martin Moos
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic
| | - Michael P. Barrett
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
| | - David Horn
- Wellcome Centre for Anti-Infectives Research, University of Dundee, Dundee, United Kingdom
| | - Alena Zíková
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic
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de Atauri P, Foguet C, Cascante M. Control analysis in the identification of key enzymes driving metabolic adaptations: Towards drug target discovery. Biosystems 2023; 231:104984. [PMID: 37506820 DOI: 10.1016/j.biosystems.2023.104984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 07/18/2023] [Accepted: 07/25/2023] [Indexed: 07/30/2023]
Abstract
Metabolic Control Analysis (MCA) marked a turning point in understanding the design principles of metabolic network control by establishing control coefficients as a means to quantify the degree of control that an enzyme exerts on flux or metabolite concentrations. MCA has demonstrated that control of metabolic pathways is distributed among many enzymes rather than depending on a single rate-limiting step. MCA also proved that this distribution depends not only on the stoichiometric structure of the network but also on other kinetic determinants, such as the degree of saturation of the enzyme active site, the distance to thermodynamic equilibrium, and metabolite feedback regulatory loops. Consequently, predicting the alterations that occur during metabolic adaptation in response to strong changes involving a redistribution in such control distribution can be challenging. Here, using the framework provided by MCA, we illustrate how control distribution in a metabolic pathway/network depends on enzyme kinetic determinants and to what extent the redistribution of control affects our predictions on candidate enzymes suitable as targets for small molecule inhibition in the drug discovery process. Our results uncover that kinetic determinants can lead to unexpected control distribution and outcomes that cannot be predicted solely from stoichiometric determinants. We also unveil that the inference of key enzyme-drivers of an observed metabolic adaptation can be dramatically improved using mean control coefficients and ruling out those enzyme activities that are associated with low control coefficients. As the use of constraint-based stoichiometric genome-scale metabolic models (GSMMs) becomes increasingly prevalent for identifying genes/enzymes that could be potential drug targets, we anticipate that incorporating kinetic determinants and ruling out enzymes with low control coefficients into GSMM workflows will facilitate more accurate predictions and reveal novel therapeutic targets.
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Affiliation(s)
- Pedro de Atauri
- Department of Biochemistry and Molecular Biomedicine & Institute of Biomedicine of Universitat de Barcelona, Faculty of Biology, Universitat de Barcelona, Barcelona, 08028, Spain; Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Instituto de Salud Carlos III (ISCIII), Madrid, 28020, Spain.
| | - Carles Foguet
- British Heart Foundation Cardiovascular Epidemiology Unit and Victor Phillip Dahdaleh Heart and Lung Research Institute, University of Cambridge, Cambridge, CB2 0BD, United Kingdom
| | - Marta Cascante
- Department of Biochemistry and Molecular Biomedicine & Institute of Biomedicine of Universitat de Barcelona, Faculty of Biology, Universitat de Barcelona, Barcelona, 08028, Spain; Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Instituto de Salud Carlos III (ISCIII), Madrid, 28020, Spain.
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Andrade-Alviárez D, Bonive-Boscan AD, Cáceres AJ, Quiñones W, Gualdrón-López M, Ginger ML, Michels PAM. Delineating transitions during the evolution of specialised peroxisomes: Glycosome formation in kinetoplastid and diplonemid protists. Front Cell Dev Biol 2022; 10:979269. [PMID: 36172271 PMCID: PMC9512073 DOI: 10.3389/fcell.2022.979269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 08/17/2022] [Indexed: 12/01/2022] Open
Abstract
One peculiarity of protists belonging to classes Kinetoplastea and Diplonemea within the phylum Euglenozoa is compartmentalisation of most glycolytic enzymes within peroxisomes that are hence called glycosomes. This pathway is not sequestered in peroxisomes of the third Euglenozoan class, Euglenida. Previous analysis of well-studied kinetoplastids, the ‘TriTryps’ parasites Trypanosoma brucei, Trypanosoma cruzi and Leishmania spp., identified within glycosomes other metabolic processes usually not present in peroxisomes. In addition, trypanosomatid peroxins, i.e. proteins involved in biogenesis of these organelles, are divergent from human and yeast orthologues. In recent years, genomes, transcriptomes and proteomes for a variety of euglenozoans have become available. Here, we track the possible evolution of glycosomes by querying these databases, as well as the genome of Naegleria gruberi, a non-euglenozoan, which belongs to the same protist supergroup Discoba. We searched for orthologues of TriTryps proteins involved in glycosomal metabolism and biogenesis. Predicted cellular location(s) of each metabolic enzyme identified was inferred from presence or absence of peroxisomal-targeting signals. Combined with a survey of relevant literature, we refine extensively our previously postulated hypothesis about glycosome evolution. The data agree glycolysis was compartmentalised in a common ancestor of the kinetoplastids and diplonemids, yet additionally indicates most other processes found in glycosomes of extant trypanosomatids, but not in peroxisomes of other eukaryotes were either sequestered in this ancestor or shortly after separation of the two lineages. In contrast, peroxin divergence is evident in all euglenozoans. Following their gain of pathway complexity, subsequent evolution of peroxisome/glycosome function is complex. We hypothesize compartmentalisation in glycosomes of glycolytic enzymes, their cofactors and subsequently other metabolic enzymes provided selective advantage to kinetoplastids and diplonemids during their evolution in changing marine environments. We contend two specific properties derived from the ancestral peroxisomes were key: existence of nonselective pores for small solutes and the possibility of high turnover by pexophagy. Critically, such pores and pexophagy are characterised in extant trypanosomatids. Increasing amenability of free-living kinetoplastids and recently isolated diplonemids to experimental study means our hypothesis and interpretation of bioinformatic data are suited to experimental interrogation.
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Affiliation(s)
- Diego Andrade-Alviárez
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida, Venezuela
| | - Alejandro D. Bonive-Boscan
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida, Venezuela
| | - Ana J. Cáceres
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida, Venezuela
| | - Wilfredo Quiñones
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida, Venezuela
| | | | - Michael L. Ginger
- School of Applied Sciences, University of Huddersfield, Huddersfield, United Kingdom
| | - Paul A. M. Michels
- Centre for Immunity, Infection and Evolution and Centre for Translational and Chemical Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, United Kingdom
- *Correspondence: Paul A. M. Michels,
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Michels PAM, Villafraz O, Pineda E, Alencar MB, Cáceres AJ, Silber AM, Bringaud F. Carbohydrate metabolism in trypanosomatids: New insights revealing novel complexity, diversity and species-unique features. Exp Parasitol 2021; 224:108102. [PMID: 33775649 DOI: 10.1016/j.exppara.2021.108102] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 03/13/2021] [Accepted: 03/18/2021] [Indexed: 12/16/2022]
Abstract
The human pathogenic trypanosomatid species collectively called the "TriTryp parasites" - Trypanosoma brucei, Trypanosoma cruzi and Leishmania spp. - have complex life cycles, with each of these parasitic protists residing in a different niche during their successive developmental stages where they encounter diverse nutrients. Consequently, they adapt their metabolic network accordingly. Yet, throughout the life cycles, carbohydrate metabolism - involving the glycolytic, gluconeogenic and pentose-phosphate pathways - always plays a central role in the biology of these parasites, whether the available carbon and free energy sources are saccharides, amino acids or lipids. In this paper, we provide an updated review of the carbohydrate metabolism of the TriTryps, highlighting new data about this metabolic network, the interconnection of its pathways and the compartmentalisation of its enzymes within glycosomes, cytosol and mitochondrion. Differences in the expression of the branches of the metabolic network between the successive life-cycle stages of each of these parasitic trypanosomatids are discussed, as well as differences between them. Recent structural and kinetic studies have revealed unique regulatory mechanisms for some of the network's key enzymes with important species-specific variations. Furthermore, reports of multiple post-translational modifications of trypanosomal glycolytic enzymes suggest that additional mechanisms for stage- and/or environmental cues that regulate activity are operational in the parasites. The detailed comparison of the carbohydrate metabolism of the TriTryps has thus revealed multiple differences and a greater complexity, including for the reduced metabolic network in bloodstream-form T. brucei, than previously appreciated. Although these parasites are related, share many cytological and metabolic features and are grouped within a single taxonomic family, the differences highlighted in this review reflect their separate evolutionary tracks from a common ancestor to the extant organisms. These differences are indicative of their adaptation to the different insect vectors and niches occupied in their mammalian hosts.
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Affiliation(s)
- Paul A M Michels
- Centre for Immunity, Infection and Evolution and Centre for Translational and Chemical Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, United Kingdom.
| | - Oriana Villafraz
- Laboratoire de Microbiologie Fondamentale et Pathogénicité (MFP), Université de Bordeaux, CNRS UMR-5234, France
| | - Erika Pineda
- Laboratoire de Microbiologie Fondamentale et Pathogénicité (MFP), Université de Bordeaux, CNRS UMR-5234, France
| | - Mayke B Alencar
- Laboratory of Biochemistry of Tryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, 05508-000, Brazil
| | - Ana J Cáceres
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida, 5101, Venezuela.
| | - Ariel M Silber
- Laboratory of Biochemistry of Tryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, 05508-000, Brazil.
| | - Frédéric Bringaud
- Laboratoire de Microbiologie Fondamentale et Pathogénicité (MFP), Université de Bordeaux, CNRS UMR-5234, France.
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Biochemical and transcript level differences between the three human phosphofructokinases show optimisation of each isoform for specific metabolic niches. Biochem J 2021; 477:4425-4441. [PMID: 33141153 PMCID: PMC7702303 DOI: 10.1042/bcj20200656] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/01/2020] [Accepted: 11/03/2020] [Indexed: 01/14/2023]
Abstract
6-Phosphofructokinase-1-kinase (PFK) tetramers catalyse the phosphorylation of fructose 6-phosphate (F6P) to fructose 1,6-bisphosphate (F16BP). Vertebrates have three PFK isoforms (PFK-M, PFK-L, and PFK-P). This study is the first to compare the kinetics, structures, and transcript levels of recombinant human PFK isoforms. Under the conditions tested PFK-M has the highest affinities for F6P and ATP (K0.5ATP 152 µM; K0.5F6P 147 µM), PFK-P the lowest affinities (K0.5ATP 276 µM; K0.5F6P 1333 µM), and PFK-L demonstrates a mixed picture of high ATP affinity and low F6P affinity (K0.5ATP 160 µM; K0.5F6P 1360 µM). PFK-M is more resistant to ATP inhibition compared with PFK-L and PFK-P (respectively, 23%, 31%, 50% decreases in specificity constants). GTP is an alternate phospho donor. Interface 2, which regulates the inactive dimer to active tetramer equilibrium, differs between isoforms, resulting in varying tetrameric stability. Under the conditions tested PFK-M is less sensitive to fructose 2,6-bisphosphate (F26BP) allosteric modulation than PFK-L or PFK-P (allosteric constants [K0.5ATP+F26BP/K0.5ATP] 1.10, 0.92, 0.54, respectively). Structural analysis of two allosteric sites reveals one may be specialised for AMP/ADP and the other for smaller/flexible regulators (citrate or phosphoenolpyruvate). Correlations between PFK-L and PFK-P transcript levels indicate that simultaneous expression may expand metabolic capacity for F16BP production whilst preserving regulatory capabilities. Analysis of cancer samples reveals intriguing parallels between PFK-P and PKM2 (pyruvate kinase M2), and simultaneous increases in PFK-P and PFKFB3 (responsible for F26BP production) transcript levels, suggesting prioritisation of metabolic flexibility in cancers. Our results describe the kinetic and transcript level differences between the three PFK isoforms, explaining how each isoform may be optimised for distinct roles.
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McNae IW, Kinkead J, Malik D, Yen LH, Walker MK, Swain C, Webster SP, Gray N, Fernandes PM, Myburgh E, Blackburn EA, Ritchie R, Austin C, Wear MA, Highton AJ, Keats AJ, Vong A, Dornan J, Mottram JC, Michels PAM, Pettit S, Walkinshaw MD. Fast acting allosteric phosphofructokinase inhibitors block trypanosome glycolysis and cure acute African trypanosomiasis in mice. Nat Commun 2021; 12:1052. [PMID: 33594070 PMCID: PMC7887271 DOI: 10.1038/s41467-021-21273-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 01/11/2021] [Indexed: 12/13/2022] Open
Abstract
The parasitic protist Trypanosoma brucei is the causative agent of Human African Trypanosomiasis, also known as sleeping sickness. The parasite enters the blood via the bite of the tsetse fly where it is wholly reliant on glycolysis for the production of ATP. Glycolytic enzymes have been regarded as challenging drug targets because of their highly conserved active sites and phosphorylated substrates. We describe the development of novel small molecule allosteric inhibitors of trypanosome phosphofructokinase (PFK) that block the glycolytic pathway resulting in very fast parasite kill times with no inhibition of human PFKs. The compounds cross the blood brain barrier and single day oral dosing cures parasitaemia in a stage 1 animal model of human African trypanosomiasis. This study demonstrates that it is possible to target glycolysis and additionally shows how differences in allosteric mechanisms may allow the development of species-specific inhibitors to tackle a range of proliferative or infectious diseases.
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Affiliation(s)
- Iain W McNae
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, UK
| | - James Kinkead
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, UK
| | - Divya Malik
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, UK
| | - Li-Hsuan Yen
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, UK
| | - Martin K Walker
- Selcia Ltd., Fyfield Business and Research Park, Fyfield Road, Ongar, Essex, UK
| | | | - Scott P Webster
- Centre for Cardiovascular Science, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, UK
| | - Nick Gray
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, UK
| | - Peter M Fernandes
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, UK
| | - Elmarie Myburgh
- York Biomedical Research Institute, Hull York Medical School, University of York, York, UK
| | - Elizabeth A Blackburn
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, UK
| | - Ryan Ritchie
- Institute of Infection Immunity and Inflammation, College of Medical Veterinary Life-Sciences, University of Glasgow, Glasgow, UK
| | - Carol Austin
- Selcia Ltd., Fyfield Business and Research Park, Fyfield Road, Ongar, Essex, UK
| | - Martin A Wear
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, UK
| | - Adrian J Highton
- Selcia Ltd., Fyfield Business and Research Park, Fyfield Road, Ongar, Essex, UK
| | - Andrew J Keats
- Selcia Ltd., Fyfield Business and Research Park, Fyfield Road, Ongar, Essex, UK
| | - Antonio Vong
- Selcia Ltd., Fyfield Business and Research Park, Fyfield Road, Ongar, Essex, UK
| | - Jacqueline Dornan
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, UK
| | - Jeremy C Mottram
- York Biomedical Research Institute, Department of Biology, University of York, York, UK
| | - Paul A M Michels
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, UK
| | - Simon Pettit
- Selcia Ltd., Fyfield Business and Research Park, Fyfield Road, Ongar, Essex, UK.
| | - Malcolm D Walkinshaw
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, UK.
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Snášel J, Machová I, Šolínová V, Kašička V, Krečmerová M, Pichová I. Phosphofructokinases A and B from Mycobacterium tuberculosis Display Different Catalytic Properties and Allosteric Regulation. Int J Mol Sci 2021; 22:1483. [PMID: 33540748 PMCID: PMC7867265 DOI: 10.3390/ijms22031483] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 01/28/2021] [Accepted: 01/29/2021] [Indexed: 11/16/2022] Open
Abstract
Tuberculosis (TB) remains one of the major health concerns worldwide. Mycobacterium tuberculosis (Mtb), the causative agent of TB, can flexibly change its metabolic processes during different life stages. Regulation of key metabolic enzyme activities by intracellular conditions, allosteric inhibition or feedback control can effectively contribute to Mtb survival under different conditions. Phosphofructokinase (Pfk) is one of the key enzymes regulating glycolysis. Mtb encodes two Pfk isoenzymes, Pfk A/Rv3010c and Pfk B/Rv2029c, which are differently expressed upon transition to the hypoxia-induced non-replicating state of the bacteria. While pfkB gene and protein expression are upregulated under hypoxic conditions, Pfk A levels decrease. Here, we present biochemical characterization of both Pfk isoenzymes, revealing that Pfk A and Pfk B display different kinetic properties. Although the glycolytic activity of Pfk A is higher than that of Pfk B, it is markedly inhibited by an excess of both substrates (fructose-6-phosphate and ATP), reaction products (fructose-1,6-bisphosphate and ADP) and common metabolic allosteric regulators. In contrast, synthesis of fructose-1,6-bisphosphatase catalyzed by Pfk B is not regulated by higher levels of substrates, and metabolites. Importantly, we found that only Pfk B can catalyze the reverse gluconeogenic reaction. Pfk B thus can support glycolysis under conditions inhibiting Pfk A function.
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Affiliation(s)
| | | | | | | | | | - Iva Pichová
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, 16610 Prague 6, Czech Republic; (J.S.); (I.M.); (V.Š.); (V.K.); (M.K.)
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Fernandes PM, Kinkead J, McNae IW, Vásquez-Valdivieso M, Wear MA, Michels PAM, Walkinshaw MD. Kinetic and structural studies of Trypanosoma and Leishmania phosphofructokinases show evolutionary divergence and identify AMP as a switch regulating glycolysis versus gluconeogenesis. FEBS J 2020; 287:2847-2861. [PMID: 31838765 PMCID: PMC7383607 DOI: 10.1111/febs.15177] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 11/13/2019] [Accepted: 12/12/2019] [Indexed: 11/30/2022]
Abstract
Trypanosomatids possess glycosome organelles that contain much of the glycolytic machinery, including phosphofructokinase (PFK). We present kinetic and structural data for PFK from three human pathogenic trypanosomatids, illustrating intriguing differences that may reflect evolutionary adaptations to differing ecological niches. The activity of Leishmania PFK – to a much larger extent than Trypanosoma PFK – is reliant on AMP for activity regulation, with 1 mm AMP increasing the L. infantum PFK (LiPFK) kcat/K0.5F6P value by 10‐fold, compared to only a 1.3‐ and 1.4‐fold increase for T. cruzi and T. brucei PFK, respectively. We also show that Leishmania PFK melts at a significantly lower (> 15 °C) temperature than Trypanosoma PFKs and that addition of either AMP or ATP results in a marked stabilization of the protein. Sequence comparisons of Trypanosoma spp. and Leishmania spp. show that divergence of the two genera involved amino acid substitutions that occur in the enzyme’s ‘reaching arms’ and ‘embracing arms’ that determine tetramer stability. The dramatic effects of AMP on Leishmania activity compared with the Trypanosoma PFKs may be explained by differences between the T‐to‐R equilibria for the two families, with the low‐melting Leishmania PFK favouring the flexible inactive T‐state in the absence of AMP. Sequence comparisons along with the enzymatic and structural data presented here also suggest there was a loss of AMP‐dependent regulation in Trypanosoma species rather than gain of this characteristic in Leishmania species and that AMP acts as a key regulator in Leishmania governing the balance between glycolysis and gluconeogenesis.
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Affiliation(s)
- Peter M Fernandes
- Centre for Translational and Chemical Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, UK
| | - James Kinkead
- Centre for Translational and Chemical Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, UK
| | - Iain W McNae
- Centre for Translational and Chemical Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, UK
| | - Monserrat Vásquez-Valdivieso
- Centre for Translational and Chemical Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, UK
| | - Martin A Wear
- Centre for Translational and Chemical Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, UK
| | - Paul A M Michels
- Centre for Translational and Chemical Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, UK
| | - Malcolm D Walkinshaw
- Centre for Translational and Chemical Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, UK
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