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Taylor JL, Ayres-Galhardo PH, Brown BL. Elucidating the Role of Human ALAS2 C-terminal Mutations Resulting in Loss of Function and Disease. Biochemistry 2024. [PMID: 38888931 DOI: 10.1021/acs.biochem.4c00066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
The conserved enzyme aminolevulinic acid synthase (ALAS) initiates heme biosynthesis in certain bacteria and eukaryotes by catalyzing the condensation of glycine and succinyl-CoA to yield aminolevulinic acid. In humans, the ALAS isoform responsible for heme production during red blood cell development is the erythroid-specific ALAS2 isoform. Owing to its essential role in erythropoiesis, changes in human ALAS2 (hALAS2) function can lead to two different blood disorders. X-linked sideroblastic anemia results from loss of ALAS2 function, while X-linked protoporphyria results from gain of ALAS2 function. Interestingly, mutations in the ALAS2 C-terminal extension can be implicated in both diseases. Here, we investigate the molecular basis for enzyme dysfunction mediated by two previously reported C-terminal loss-of-function variants, hALAS2 V562A and M567I. We show that the mutations do not result in gross structural perturbations, but the enzyme stability for V562A is decreased. Additionally, we show that enzyme stability moderately increases with the addition of the pyridoxal 5'-phosphate (PLP) cofactor for both variants. The variants display differential binding to PLP and the individual substrates compared to wild-type hALAS2. Although hALAS2 V562A is a more active enzyme in vitro, it is less efficient concerning succinyl-CoA binding. In contrast, the M567I mutation significantly alters the cooperativity of substrate binding. In combination with previously reported cell-based studies, our work reveals the molecular basis by which hALAS2 C-terminal mutations negatively affect ALA production necessary for proper heme biosynthesis.
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2
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Aftab H, Donegan RK. Regulation of heme biosynthesis via the coproporphyrin dependent pathway in bacteria. Front Microbiol 2024; 15:1345389. [PMID: 38577681 PMCID: PMC10991733 DOI: 10.3389/fmicb.2024.1345389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 03/08/2024] [Indexed: 04/06/2024] Open
Abstract
Heme biosynthesis in the Gram-positive bacteria occurs mostly via a pathway that is distinct from that of eukaryotes and Gram-negative bacteria in the three terminal heme synthesis steps. In many of these bacteria heme is a necessary cofactor that fulfills roles in respiration, gas sensing, and detoxification of reactive oxygen species. These varying roles for heme, the requirement of iron and glutamate, as glutamyl tRNA, for synthesis, and the sharing of intermediates with the synthesis of other porphyrin derivatives necessitates the need for many points of regulation in response to nutrient availability and metabolic state. In this review we examine the regulation of heme biosynthesis in these bacteria via heme, iron, and oxygen species. We also discuss our perspective on emerging roles of protein-protein interactions and post-translational modifications in regulating heme biosynthesis.
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Gabler T, Dali A, Bellei M, Sebastiani F, Becucci M, Battistuzzi G, Furtmüller PG, Smulevich G, Hofbauer S. Revisiting catalytic His and Glu residues in coproporphyrin ferrochelatase - unexpected activities of active site variants. FEBS J 2024. [PMID: 38390750 DOI: 10.1111/febs.17101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/17/2024] [Accepted: 02/13/2024] [Indexed: 02/24/2024]
Abstract
The identification of the coproporphyrin-dependent heme biosynthetic pathway, which is used almost exclusively by monoderm bacteria in 2015 by Dailey et al. triggered studies aimed at investigating the enzymes involved in this pathway that were originally assigned to the protoporphyrin-dependent heme biosynthetic pathway. Here, we revisit the active site of coproporphyrin ferrochelatase by a biophysical and biochemical investigation using the physiological substrate coproporphyrin III, which in contrast to the previously used substrate protoporphyrin IX has four propionate substituents and no vinyl groups. In particular, we have compared the reactivity of wild-type coproporphyrin ferrochelatase from the firmicute Listeria monocytogenes with those of variants, namely, His182Ala (H182A) and Glu263Gln (E263Q), involving two key active site residues. Interestingly, both variants are active only toward the physiological substrate coproporphyrin III but inactive toward protoporphyrin IX. In addition, E263 exchange impairs the final oxidation step from ferrous coproheme to ferric coproheme. The characteristics of the active site in the context of the residues involved and the substrate binding properties are discussed here using structural and functional means, providing a further contribution to the deciphering of this enigmatic reaction mechanism.
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Affiliation(s)
- Thomas Gabler
- Department of Chemistry, Institute of Biochemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Andrea Dali
- Department of Chemistry "Ugo Schiff" (DICUS), University of Florence, Sesto Fiorentino, Italy
| | - Marzia Bellei
- Department of Life Sciences, University of Modena and Reggio Emilia, Italy
| | - Federico Sebastiani
- Department of Chemistry "Ugo Schiff" (DICUS), University of Florence, Sesto Fiorentino, Italy
| | - Maurizio Becucci
- Department of Chemistry "Ugo Schiff" (DICUS), University of Florence, Sesto Fiorentino, Italy
| | - Gianantonio Battistuzzi
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Paul Georg Furtmüller
- Department of Chemistry, Institute of Biochemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Giulietta Smulevich
- Department of Chemistry "Ugo Schiff" (DICUS), University of Florence, Sesto Fiorentino, Italy
- INSTM Research Unit of Firenze, Sesto Fiorentino, Italy
| | - Stefan Hofbauer
- Department of Chemistry, Institute of Biochemistry, University of Natural Resources and Life Sciences, Vienna, Austria
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Graf J, Schöpperle M, Pernil R, Schleiff E. Two TonB-dependent outer membrane transporters involved in heme uptake in Anabaena sp. PCC 7120. MICROBIAL CELL (GRAZ, AUSTRIA) 2024; 11:16-28. [PMID: 38234586 PMCID: PMC10792254 DOI: 10.15698/mic2024.01.812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Revised: 11/03/2023] [Accepted: 11/13/2023] [Indexed: 01/19/2024]
Abstract
Low availability of micronutrients such as iron has enforced the evolution of uptake systems in all kingdoms of life. In Gram-negative bacteria, outer membrane, periplasmatic and plasma membrane localized proteins facilitate the uptake of iron-loaded chelators, which are energized by TonB proteins. The specificity of different uptake systems likely depends either on the endogenously produced siderophore or on the bioavailability of iron-chelator complexes in the environment. Hence, an uptake system for schizokinen produced by the model cyanobacterium Anabaena sp. PCC 7120 exists, while bioinformatics analysis suggests the existence of additional systems, likely for uptake of xenosiderophores. Consistently, proteins encoded by alr2153 (hutA1) and alr3242 (hutA2) are assigned as outer membrane heme transporters. Indeed, Anabaena sp. PCC 7120 can utilize external heme as an iron source. The addition of heme resulted in an induction of genes involved in heme degradation and chlorophyll a synthesis and in an increase of the chlorophyll a content. Moreover, iron starvation induced the expression of hutA1, while the addition of heme led to its repression. Remarkably, the addition of a high concentration of heme but not iron starvation resulted in hutA2 induction. Plasmid insertion mutants of both genes exhibited a reduced capacity to recover from iron starvation by heme addition, which indicates a dependence of heme uptake on functional HutA1 and HutA2 proteins. The structural model generated by bioinformatics methods is further in agreement with a role in heme uptake. Thus, we provide evidence that Anabaena sp. PCC 7120 uses a heme uptake system in parallel to other iron acquisition systems.
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Affiliation(s)
- Julia Graf
- Institute for Molecular Biosciences, Goethe University Frankfurt, Max von Laue Str. 9, 60438 Frankfurt, Germany
| | - Martin Schöpperle
- Institute for Molecular Biosciences, Goethe University Frankfurt, Max von Laue Str. 9, 60438 Frankfurt, Germany
- Current address: Lonza Cologne GmbH, Köln, Germany:
| | - Rafael Pernil
- Institute for Molecular Biosciences, Goethe University Frankfurt, Max von Laue Str. 9, 60438 Frankfurt, Germany
| | - Enrico Schleiff
- Institute for Molecular Biosciences, Goethe University Frankfurt, Max von Laue Str. 9, 60438 Frankfurt, Germany
- Frankfurt Institute for Advanced Studies, Ruth-Moufang-Straße 1, 60438 Frankfurt, Germany
- Buchmann Institute for Molecular Life Sciences, Max von Laue Str. 11, 60438 Frankfurt, Germany
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Zámocký M, Hofbauer S, Gabler T, Furtmüller PG. The Molecular Evolution, Structure, and Function of Coproporphyrinogen Oxidase and Protoporphyrinogen Oxidase in Prokaryotes. BIOLOGY 2023; 12:1527. [PMID: 38132353 PMCID: PMC10740692 DOI: 10.3390/biology12121527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 12/08/2023] [Accepted: 12/11/2023] [Indexed: 12/23/2023]
Abstract
Coproporphyrinogen oxidase (CgoX) and protoporphyrinogen oxidase (PgoX) catalyze the oxidation of the flexible cyclic tetrapyrrole of porphyrinogen compounds into fully conjugated, planar macrocyclic porphyrin compounds during heme biosynthesis. These enzymes are activated via different pathways. CgoX oxidizes coproporphyrinogen III to coproporphyrin III in the coproporphyrin-dependent pathway, whereas PgoX oxidizes protoporphyrinogen IX to protoporphyrin IX in the penultimate step of the protoporphyrin-dependent pathway. The phylogenetic analysis presented herein demonstrates a clear differentiation between the two enzyme classes, as evidenced by the clustering of sequences in distinct clades, and it shows that, at the origin of porphyrinogen-type oxidase evolution, PgoXs from cyanobacteria were found, which were noticeably separated from descendant PgoX representatives of Deltaproteobacteria and all later PgoX variants, leading to many eukaryotic clades. CgoX sequences originating from the monoderm Actinomycetota and Bacillota were well separated from the predecessor clades containing PgoX types and represent a peculiar type of gene speciation. The structural similarities and differences between these two oxidases are discussed based on their protein sequence alignment and a structural comparison.
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Affiliation(s)
- Marcel Zámocký
- Laboratory of Phylogenomic Ecology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská Cesta 21, SK-84551 Bratislava, Slovakia;
- Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská Dolina, Ilkovičova 6, SK-84215 Bratislava, Slovakia
| | - Stefan Hofbauer
- Institute of Biochemistry, Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, A-1190 Vienna, Austria; (S.H.); (T.G.)
| | - Thomas Gabler
- Institute of Biochemistry, Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, A-1190 Vienna, Austria; (S.H.); (T.G.)
| | - Paul G. Furtmüller
- Institute of Biochemistry, Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, A-1190 Vienna, Austria; (S.H.); (T.G.)
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Duerre DJ, Hansen JK, John S, Jen A, Carrillo N, Bui H, Bao Y, Fabregat M, Overmeyer K, Shishkova E, Keller MP, Anderson RA, Cryns VL, Attie AD, Coon JJ, Fan J, Galmozzi A. Heme biosynthesis regulates BCAA catabolism and thermogenesis in brown adipose tissue. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.28.568893. [PMID: 38076785 PMCID: PMC10705273 DOI: 10.1101/2023.11.28.568893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
With age, people tend to accumulate body fat and reduce energy expenditure 1 . Brown (BAT) and beige adipose tissue dissipate heat and increase energy expenditure via the activity of the uncoupling protein UCP1 and other thermogenic futile cycles 2,3 . The activity of brown and beige depots inversely correlates with BMI and age 4-11 , suggesting that promoting thermogenesis may be an effective approach for combating age-related metabolic disease 12-15 . Heme is an enzyme cofactor and signaling molecule that we recently showed to regulate BAT function 16 . Here, we show that heme biosynthesis is the primary contributor to intracellular heme levels in brown adipocytes. Inhibition of heme biosynthesis leads to mitochondrial dysfunction and reduction in UCP1. Although supplementing heme can restore mitochondrial function in heme-synthesis-deficient cells, the downregulation of UCP1 persists due to the accumulation of the heme precursors, particularly propionyl-CoA, which is a product of branched-chain amino acids (BCAA) catabolism. Cold exposure promotes BCAA uptake in BAT, and defects in BCAA catabolism in this tissue hinder thermogenesis 17 . However, BCAAs' contribution to the TCA cycle in BAT and WAT never exceeds 2% of total TCA flux 18 . Our work offers a way to integrate current literature by describing heme biosynthesis as an important metabolic sink for BCAAs.
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Zamarreño Beas J, Videira MAM, Karavaeva V, Lourenço FM, Almeida MR, Sousa F, Saraiva LM. In Campylobacter jejuni, a new type of chaperone receives heme from ferrochelatase. Front Genet 2023; 14:1199357. [PMID: 37415606 PMCID: PMC10320005 DOI: 10.3389/fgene.2023.1199357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 06/02/2023] [Indexed: 07/08/2023] Open
Abstract
Intracellular heme formation and trafficking are fundamental processes in living organisms. Bacteria and archaea utilize three biogenesis pathways to produce iron protoporphyrin IX (heme b) that diverge after the formation of the common intermediate uroporphyrinogen III (uro'gen III). In this study, we identify and provide a detailed characterization of the enzymes involved in the transformation of uro'gen III into heme in Campylobacter jejuni, demonstrating that this bacterium utilizes the protoporphyrin-dependent (PPD) pathway. In general, limited knowledge exists regarding the mechanisms by which heme b reaches its target proteins after this final step. Specifically, the chaperones necessary for trafficking heme to prevent the cytotoxic effects associated with free heme remain largely unidentified. In C. jejuni, we identified a protein named CgdH2 that binds heme with a dissociation constant of 4.9 ± 1.0 µM, and this binding is impaired upon mutation of residues histidine 45 and 133. We demonstrate that C. jejuni CgdH2 establishes protein-protein interactions with ferrochelatase, suggesting its role in facilitating heme transfer from ferrochelatase to CgdH2. Furthermore, phylogenetic analysis reveals that C. jejuni CgdH2 is evolutionarily distinct from the currently known chaperones. Therefore, CgdH2 is the first protein identified as an acceptor of intracellularly formed heme, expanding our knowledge of the mechanisms underlying heme trafficking within bacterial cells.
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Affiliation(s)
- Jordi Zamarreño Beas
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Marco A. M. Videira
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Val Karavaeva
- Department of Functional and Evolutionary Ecology, University of Vienna, Wien, Austria
| | - Frederico M. Lourenço
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Mafalda R. Almeida
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Filipa Sousa
- Department of Functional and Evolutionary Ecology, University of Vienna, Wien, Austria
| | - Lígia M. Saraiva
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
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Patil G, Michlits H, Furtmüller PG, Hofbauer S. Reactivity of Coproheme Decarboxylase with Monovinyl, Monopropionate Deuteroheme. Biomolecules 2023; 13:946. [PMID: 37371526 PMCID: PMC10296651 DOI: 10.3390/biom13060946] [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: 04/28/2023] [Revised: 05/23/2023] [Accepted: 06/02/2023] [Indexed: 06/29/2023] Open
Abstract
Coproheme decarboxylases (ChdCs) are terminal enzymes of the coproporphyrin-dependent heme biosynthetic pathway. In this reaction, two propionate groups are cleaved from the redox-active iron-containing substrate, coproheme, to form vinyl groups of the heme b product. The two decarboxylation reactions proceed sequentially, and a redox-active three-propionate porphyrin, called monovinyl, monopropionate deuteroheme (MMD), is transiently formed as an intermediate. While the reaction mechanism for the first part of the redox reaction, which is initiated by hydrogen peroxide, has been elucidated in some detail, the second part of this reaction, starting from MMD, has not been studied. Here, we report the optimization of enzymatic MMD production by ChdC and purification by reversed-phase chromatography. With the obtained MMD, we were able to study the second part of heme b formation by actinobacterial ChdC from Corynebacterium diphtheriae, starting with Compound I formation upon the addition of hydrogen peroxide. The results indicate that the second part of the decarboxylation reaction is analogous to the first part, although somewhat slower, which is explained by differences in the active site architecture and its H-bonding network. The results are discussed in terms of known kinetic and structural data and help to fill some mechanistic gaps in the overall reaction catalyzed by ChdCs.
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Affiliation(s)
| | | | | | - Stefan Hofbauer
- Department of Chemistry, Institute of Biochemistry, University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
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Turilli-Ghisolfi ES, Lualdi M, Fasano M. Ligand-Based Regulation of Dynamics and Reactivity of Hemoproteins. Biomolecules 2023; 13:683. [PMID: 37189430 PMCID: PMC10135655 DOI: 10.3390/biom13040683] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 04/14/2023] [Accepted: 04/15/2023] [Indexed: 05/17/2023] Open
Abstract
Hemoproteins include several heme-binding proteins with distinct structure and function. The presence of the heme group confers specific reactivity and spectroscopic properties to hemoproteins. In this review, we provide an overview of five families of hemoproteins in terms of dynamics and reactivity. First, we describe how ligands modulate cooperativity and reactivity in globins, such as myoglobin and hemoglobin. Second, we move on to another family of hemoproteins devoted to electron transport, such as cytochromes. Later, we consider heme-based reactivity in hemopexin, the main heme-scavenging protein. Then, we focus on heme-albumin, a chronosteric hemoprotein with peculiar spectroscopic and enzymatic properties. Eventually, we analyze the reactivity and dynamics of the most recently discovered family of hemoproteins, i.e., nitrobindins.
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Affiliation(s)
| | | | - Mauro Fasano
- Department of Science and High Technology, University of Insubria, 22100 Como, Italy
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Proteomic Analysis of Ferrochelatase Interactome in Erythroid and Non-Erythroid Cells. Life (Basel) 2023; 13:life13020577. [PMID: 36836934 PMCID: PMC9958551 DOI: 10.3390/life13020577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 01/24/2023] [Accepted: 02/13/2023] [Indexed: 02/22/2023] Open
Abstract
Heme is an essential cofactor for multiple cellular processes in most organisms. In developing erythroid cells, the demand for heme synthesis is high, but is significantly lower in non-erythroid cells. While the biosynthesis of heme in metazoans is well understood, the tissue-specific regulation of the pathway is less explored. To better understand this, we analyzed the mitochondrial heme metabolon in erythroid and non-erythroid cell lines from the perspective of ferrochelatase (FECH), the terminal enzyme in the heme biosynthetic pathway. Affinity purification of FLAG-tagged-FECH, together with mass spectrometric analysis, was carried out to identify putative protein partners in human and murine cell lines. Proteins involved in the heme biosynthetic process and mitochondrial organization were identified as the core components of the FECH interactome. Interestingly, in non-erythroid cell lines, the FECH interactome is highly enriched with proteins associated with the tricarboxylic acid (TCA) cycle. Overall, our study shows that the mitochondrial heme metabolon in erythroid and non-erythroid cells has similarities and differences, and suggests new roles for the mitochondrial heme metabolon and heme in regulating metabolic flux and key cellular processes.
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Imhof D. Heme research – the past, the present and the future. Biol Chem 2022; 403:983-984. [DOI: 10.1515/hsz-2022-0307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Diana Imhof
- Pharmaceutical Biochemistry and Bioanalytics , Pharmaceutical Institute, University of Bonn , An der Immenburg 4, D-53121 Bonn , Germany
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