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Mascarenhas R, Guha A, Li Z, Ruetz M, An S, Seravalli J, Banerjee R. Cobalt-Sulfur Coordination Chemistry Drives B 12 Loading onto Methionine Synthase. J Am Chem Soc 2023:10.1021/jacs.3c07941. [PMID: 37916782 PMCID: PMC11063128 DOI: 10.1021/jacs.3c07941] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
Cobalt-sulfur (Co-S) coordination is labile to both oxidation and reduction chemistry and is rarely seen in nature. Cobalamin (or vitamin B12) is an essential cobalt-containing organometallic cofactor in mammals and is escorted via an intricate network of chaperones to a single cytoplasmic target, methionine synthase. In this study, we report that the human cobalamin trafficking protein, MMADHC, exploits the chemical lability of Co-S coordination for cofactor off-loading onto methionine synthase. Cys-261 on MMADHC serves as the β-axial ligand to cobalamin. Complex formation between MMADHC and methionine synthase is signaled by loss of the lower axial nitrogen ligand, leading to five-coordinate thiolato-cobalamin. Nucleophilic displacement by the vicinal thiolate, Cys-262, completes cofactor transfer to methionine synthase and release of a cysteine disulfide-containing MMADHC. The physiological relevance of this mechanism is supported by clinical variants of MMADHC, which impair cofactor binding and off-loading, explaining the molecular basis of the associated homocystinuria.
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Affiliation(s)
- Romila Mascarenhas
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Arkajit Guha
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Zhu Li
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Markus Ruetz
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Sojin An
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Javier Seravalli
- Department of Biological Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Ruma Banerjee
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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2
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Vaccaro FA, Faber DA, Andree GA, Born DA, Kang G, Fonseca DR, Jost M, Drennan CL. Structural insight into G-protein chaperone-mediated maturation of a bacterial adenosylcobalamin-dependent mutase. J Biol Chem 2023; 299:105109. [PMID: 37517695 PMCID: PMC10481361 DOI: 10.1016/j.jbc.2023.105109] [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: 05/23/2023] [Revised: 07/20/2023] [Accepted: 07/25/2023] [Indexed: 08/01/2023] Open
Abstract
G-protein metallochaperones are essential for the proper maturation of numerous metalloenzymes. The G-protein chaperone MMAA in humans (MeaB in bacteria) uses GTP hydrolysis to facilitate the delivery of adenosylcobalamin (AdoCbl) to AdoCbl-dependent methylmalonyl-CoA mutase, an essential metabolic enzyme. This G-protein chaperone also facilitates the removal of damaged cobalamin (Cbl) for repair. Although most chaperones are standalone proteins, isobutyryl-CoA mutase fused (IcmF) has a G-protein domain covalently attached to its target mutase. We previously showed that dimeric MeaB undergoes a 180° rotation to reach a state capable of GTP hydrolysis (an active G-protein state), in which so-called switch III residues of one protomer contact the G-nucleotide of the other protomer. However, it was unclear whether other G-protein chaperones also adopted this conformation. Here, we show that the G-protein domain in a fused system forms a similar active conformation, requiring IcmF oligomerization. IcmF oligomerizes both upon Cbl damage and in the presence of the nonhydrolyzable GTP analog, guanosine-5'-[(β,γ)-methyleno]triphosphate, forming supramolecular complexes observable by mass photometry and EM. Cryo-EM structural analysis reveals that the second protomer of the G-protein intermolecular dimer props open the mutase active site using residues of switch III as a wedge, allowing for AdoCbl insertion or damaged Cbl removal. With the series of structural snapshots now available, we now describe here the molecular basis of G-protein-assisted AdoCbl-dependent mutase maturation, explaining how GTP binding prepares a mutase for cofactor delivery and how GTP hydrolysis allows the mutase to capture the cofactor.
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Affiliation(s)
- Francesca A Vaccaro
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Daphne A Faber
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Gisele A Andree
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - David A Born
- Graduate Program in Biophysics, Harvard University, Cambridge, Massachusetts, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Gyunghoon Kang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Dallas R Fonseca
- Amgen Scholar Program, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Marco Jost
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Catherine L Drennan
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
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3
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Mascarenhas R, Guha A, Li Z, Ruetz M, An S, Seravalli J, Banerjee R. Cobalt-sulfur coordination chemistry drives B 12 loading onto methionine synthase. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.25.550549. [PMID: 37546824 PMCID: PMC10402061 DOI: 10.1101/2023.07.25.550549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Cobalt-sulfur (Co-S) coordination is labile to both oxidation and reduction chemistry and is rarely seen in Nature. Cobalamin (or vitamin B 12 ) is an essential cobalt-containing organometallic cofactor in mammals, and is escorted via an intricate network of chaperones to a single cytoplasmic target, methionine synthase. In this study, we report that the human cobalamin trafficking protein, MMADHC, exploits the chemical lability of Co-S coordination, for cofactor off-loading onto methionine synthase. Cys-261 on MMADHC serves as the β-axial ligand to cobalamin. Complex formation between MMADHC and methionine synthase is signaled by loss of the lower axial nitrogen ligand, leading to five-coordinate thiolato-cobalamin. Nucleophilic displacement by the vicinal thiolate, Cys-262, completes cofactor transfer to methionine synthase and release of a cysteine disulfide-containing MMADHC. The physiological relevance of this mechanism is supported by clinical variants of MMADHC, which impair cofactor binding and off-loading, explaining the molecular basis of the associated homocystinuria.
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Mascarenhas R, Ruetz M, Gouda H, Heitman N, Yaw M, Banerjee R. Architecture of the human G-protein-methylmalonyl-CoA mutase nanoassembly for B 12 delivery and repair. Nat Commun 2023; 14:4332. [PMID: 37468522 PMCID: PMC10356863 DOI: 10.1038/s41467-023-40077-4] [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: 04/22/2023] [Accepted: 07/05/2023] [Indexed: 07/21/2023] Open
Abstract
G-proteins function as molecular switches to power cofactor translocation and confer fidelity in metal trafficking. The G-protein, MMAA, together with MMAB, an adenosyltransferase, orchestrate cofactor delivery and repair of B12-dependent human methylmalonyl-CoA mutase (MMUT). The mechanism by which the complex assembles and moves a >1300 Da cargo, or fails in disease, are poorly understood. Herein, we report the crystal structure of the human MMUT-MMAA nano-assembly, which reveals a dramatic 180° rotation of the B12 domain, exposing it to solvent. The complex, stabilized by MMAA wedging between two MMUT domains, leads to ordering of the switch I and III loops, revealing the molecular basis of mutase-dependent GTPase activation. The structure explains the biochemical penalties incurred by methylmalonic aciduria-causing mutations that reside at the MMAA-MMUT interfaces we identify here.
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Affiliation(s)
- Romila Mascarenhas
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Markus Ruetz
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Harsha Gouda
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Natalie Heitman
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Madeline Yaw
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Ruma Banerjee
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA.
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Mascarenhas R, Ruetz M, Gouda H, Heitman N, Yaw M, Banerjee R. Architecture of the human G-protein-methylmalonyl-CoA mutase nanoassembly for B 12 delivery and repair. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.23.533963. [PMID: 36993209 PMCID: PMC10055420 DOI: 10.1101/2023.03.23.533963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
G-proteins function as molecular switches to power cofactor translocation and confer fidelity in metal trafficking. MMAA, a G-protein motor, together with MMAB, an adenosyltransferase, orchestrate cofactor delivery and repair of B 12 -dependent human methylmalonyl-CoA mutase (MMUT). The mechanism by which the motor assembles and moves a >1300 Da cargo, or fails in disease, are poorly understood. Herein, we report the crystal structure of the human MMUT-MMAA nanomotor assembly, which reveals a dramatic 180° rotation of the B 12 domain, exposing it to solvent. The nanomotor complex, stabilized by MMAA wedging between two MMUT domains, leads to ordering of the switch I and III loops, revealing the molecular basis of mutase-dependent GTPase activation. The structure explains the biochemical penalties incurred by methylmalonic aciduria-causing mutations that reside at the newly identified MMAA-MMUT interfaces.
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Gouda H, Mascarenhas R, Ruetz M, Yaw M, Banerjee R. Bivalent molecular mimicry by ADP protects metal redox state and promotes coenzyme B 12 repair. Proc Natl Acad Sci U S A 2023; 120:e2220677120. [PMID: 36888659 PMCID: PMC10243129 DOI: 10.1073/pnas.2220677120] [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: 12/05/2022] [Accepted: 02/07/2023] [Indexed: 03/09/2023] Open
Abstract
Control over transition metal redox state is essential for metalloprotein function and can be achieved via coordination chemistry and/or sequestration from bulk solvent. Human methylmalonyl-Coenzyme A (CoA) mutase (MCM) catalyzes the isomerization of methylmalonyl-CoA to succinyl-CoA using 5'-deoxyadenosylcobalamin (AdoCbl) as a metallocofactor. During catalysis, the occasional escape of the 5'-deoxyadenosine (dAdo) moiety leaves the cob(II)alamin intermediate stranded and prone to hyperoxidation to hydroxocobalamin, which is recalcitrant to repair. In this study, we have identified the use of bivalent molecular mimicry by ADP, coopting the 5'-deoxyadenosine and diphosphate moieties in the cofactor and substrate, respectively, to protect against cob(II)alamin overoxidation on MCM. Crystallographic and electron paramagnetic resonance (EPR) data reveal that ADP exerts control over the metal oxidation state by inducing a conformational change that seals off solvent access, rather than by switching five-coordinate cob(II)alamin to the more air stable four-coordinate state. Subsequent binding of methylmalonyl-CoA (or CoA) promotes cob(II)alamin off-loading from MCM to adenosyltransferase for repair. This study identifies an unconventional strategy for controlling metal redox state by an abundant metabolite to plug active site access, which is key to preserving and recycling a rare, but essential, metal cofactor.
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Affiliation(s)
- Harsha Gouda
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI48109
| | - Romila Mascarenhas
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI48109
| | - Markus Ruetz
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI48109
| | - Madeline Yaw
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI48109
| | - Ruma Banerjee
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI48109
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Vaccaro FA, Born DA, Drennan CL. Structure of metallochaperone in complex with the cobalamin-binding domain of its target mutase provides insight into cofactor delivery. Proc Natl Acad Sci U S A 2023; 120:e2214085120. [PMID: 36787360 PMCID: PMC9974510 DOI: 10.1073/pnas.2214085120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 01/13/2023] [Indexed: 02/15/2023] Open
Abstract
G-protein metallochaperone MeaB in bacteria [methylmalonic aciduria type A (MMAA) in humans] is responsible for facilitating the delivery of adenosylcobalamin (AdoCbl) to methylmalonyl-CoA mutase (MCM), the only AdoCbl-dependent enzyme in humans. Genetic defects in the switch III region of MMAA lead to the genetic disorder methylmalonic aciduria in which the body is unable to process certain lipids. Here, we present a crystal structure of Methylobacterium extorquens MeaB bound to a nonhydrolyzable guanosine triphosphate (GTP) analog guanosine-5'-[(β,γ)-methyleno]triphosphate (GMPPCP) with the Cbl-binding domain of its target mutase enzyme (MeMCMcbl). This structure provides an explanation for the stimulation of the GTP hydrolyase activity of MeaB afforded by target protein binding. We find that upon MCMcbl association, one protomer of the MeaB dimer rotates ~180°, such that the inactive state of MeaB is converted to an active state in which the nucleotide substrate is now surrounded by catalytic residues. Importantly, it is the switch III region that undergoes the largest change, rearranging to make direct contacts with the terminal phosphate of GMPPCP. These structural data additionally provide insights into the molecular basis by which this metallochaperone contributes to AdoCbl delivery without directly binding the cofactor. Our data suggest a model in which GTP-bound MeaB stabilizes a conformation of MCM that is open for AdoCbl insertion, and GTP hydrolysis, as signaled by switch III residues, allows MCM to close and trap its cofactor. Substitutions of switch III residues destabilize the active state of MeaB through loss of protein:nucleotide and protein:protein interactions at the dimer interface, thus uncoupling GTP hydrolysis from AdoCbl delivery.
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Affiliation(s)
- Francesca A. Vaccaro
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA01239
| | - David A. Born
- Graduate Program in Biophysics, Harvard University, Cambridge, MA01238
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA01239
| | - Catherine L. Drennan
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA01239
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA01239
- HHMI,Massachusetts Institute of Technology, Cambridge, MA01239
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McCorvie TJ, Ferreira D, Yue WW, Froese DS. The complex machinery of human cobalamin metabolism. J Inherit Metab Dis 2023; 46:406-420. [PMID: 36680553 DOI: 10.1002/jimd.12593] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 01/17/2023] [Accepted: 01/19/2023] [Indexed: 01/22/2023]
Abstract
Vitamin B12 (cobalamin, Cbl) is required as a cofactor by two human enzymes, 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR) and methylmalonyl-CoA mutase (MMUT). Within the body, a vast array of transporters, enzymes and chaperones are required for the generation and delivery of these cofactor forms. How they perform these functions is dictated by the structure and interactions of the proteins involved, the molecular bases of which are only now being elucidated. In this review, we highlight recent insights into human Cbl metabolism and address open questions in the field by employing a protein structure and interactome based perspective. We discuss how three very similar proteins-haptocorrin, intrinsic factor and transcobalamin-exploit slight structural differences and unique ligand receptor interactions to effect selective Cbl absorption and internalisation. We describe recent advances in the understanding of how endocytosed Cbl is transported across the lysosomal membrane and the implications of the recently solved ABCD4 structure. We detail how MMACHC and MMADHC cooperate to modify and target cytosolic Cbl to the client enzymes MTR and MMUT using ingenious modifications to an ancient nitroreductase fold, and how MTR and MMUT link with their accessory enzymes to sustainably harness the supernucleophilic potential of Cbl. Finally, we provide an outlook on how future studies may combine structural and interactome based approaches and incorporate knowledge of post-translational modifications to bring further insights.
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Affiliation(s)
- Thomas J McCorvie
- Biosciences Institute, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Douglas Ferreira
- Biosciences Institute, The Medical School, Newcastle University, Newcastle upon Tyne, UK
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Wyatt W Yue
- Biosciences Institute, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - D Sean Froese
- Division of Metabolism and Children's Research Center, University Children's Hospital Zürich, University of Zürich, Zürich, Switzerland
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9
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Marelli C, Fouilhoux A, Benoist J, De Lonlay P, Guffon‐Fouilhoux N, Brassier A, Cano A, Chabrol B, Pennisi A, Schiff M, Acquaviva C, Murphy E, Servais A, Lachmann R. Very long-term outcomes in 23 patients with cblA type methylmalonic acidemia. J Inherit Metab Dis 2022; 45:937-951. [PMID: 35618652 PMCID: PMC9540587 DOI: 10.1002/jimd.12525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 05/16/2022] [Accepted: 05/23/2022] [Indexed: 11/10/2022]
Abstract
OBJECTIVES To present the very long-term follow up of patients with cobalamin A (cblA) deficiency. METHODS A retrospective case series of adult (>16 years) patients with molecular or enzymatic diagnosis of cblA deficiency. RESULTS We included 23 patients (mean age: 27 ± 7.6 years; mean follow-up: 24.9 ± 7.6 years). Disease onset was mostly pediatric (78% < 1 year, median = 4 months) with acute neurologic deterioration (65%). Eight patients presented with chronic symptoms, and one had an adult-onset mild cblA deficiency. Most of the patients (61%) were initially classified as vitamin B12-unresponsive methylmalonic aciduria (MMA); in vitro B12 responsiveness was subsequently found in all the tested patients (n = 13). Initial management consisted of protein restriction (57%), B12 (17%), or both (26%). The main long-term problems were intellectual disability (39%) and renal failure (30%). However, 56.5% of the patients were living independently. Intellectual disability was equally distributed among the initial treatment groups, while renal failure (moderate and beginning at the age of 38 years) was present in only one out of seven patients initially treated with B12. CONCLUSIONS We provide a detailed picture of the long-term outcome of a series of adult cblA patients, mostly diagnosed before the enzymatic and molecular era. We confirm that about 35% of the patients do not present acutely, underlining the importance of measuring MMA in any case of unexplained chronic renal failure, intellectual disability, or growth delay. In addition, we describe a patient with a milder adult-onset form. Early B12 supplementation seems to protect from severe renal insufficiency.
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Affiliation(s)
- Cecilia Marelli
- Expert Centre for Neurogenetic Diseases and Adult Mitochondrial and Metabolic DiseasesUniversity Hospital of MontpellierMontpellierFrance
- MMDNUniversity of Montpellier, Ecole Pratique des Hautes Etudes, InsermMontpellierFrance
| | - Alain Fouilhoux
- Reference Center for Inborn Error of MetabolismHôpital Femme Mère Enfant, Hospices Civils de LyonBronFrance
| | - Jean‐Francois Benoist
- Inserm UMR_S1163Institut ImagineParisFrance
- Biochemistry DepartmentHôpital Necker Enfants Malades, Assistance Publique – Hôpitaux de ParisParisFrance
| | - Pascale De Lonlay
- Necker Hospital, Assistance Publique – Hôpitaux de Paris, Reference Center for Inborn Error of Metabolism and Filière G2M, Pediatrics DepartmentUniversity of ParisParisFrance
| | - Nathalie Guffon‐Fouilhoux
- Reference Center for Inborn Error of MetabolismHôpital Femme Mère Enfant, Hospices Civils de LyonBronFrance
| | - Anais Brassier
- Necker Hospital, Assistance Publique – Hôpitaux de Paris, Reference Center for Inborn Error of Metabolism and Filière G2M, Pediatrics DepartmentUniversity of ParisParisFrance
| | - Aline Cano
- Reference Center for Inherited Metabolic Disorders, Assistance Publique Hôpitaux de MarseilleCentre Hospitalier Universitaire de La Timone EnfantsMarseilleFrance
| | - Brigitte Chabrol
- Reference Center for Inherited Metabolic Disorders, Assistance Publique Hôpitaux de MarseilleCentre Hospitalier Universitaire de La Timone EnfantsMarseilleFrance
| | - Alessandra Pennisi
- Necker Hospital, Assistance Publique – Hôpitaux de Paris, Reference Center for Inborn Error of Metabolism and Filière G2M, Pediatrics DepartmentUniversity of ParisParisFrance
| | - Manuel Schiff
- Inserm UMR_S1163Institut ImagineParisFrance
- Necker Hospital, Assistance Publique – Hôpitaux de Paris, Reference Center for Inborn Error of Metabolism and Filière G2M, Pediatrics DepartmentUniversity of ParisParisFrance
| | - Cecile Acquaviva
- Center for Inherited Metabolic Disorders and Neonatal Screening, Est Biology and Pathology Department, Groupement Hospitalier Est (GHE)Hospices Civils de LyonBronFrance
| | - Elaine Murphy
- C. Dent Adult Metabolic UnitNational Hospital for Neurology and NeurosurgeryLondonUK
| | - Aude Servais
- Necker Hospital, Assistance Publique – Hôpitaux de Paris, Reference Center for Inborn Error of Metabolism and Filière G2M, Pediatrics DepartmentUniversity of ParisParisFrance
- Adult Nephrology and Transplantation DepartmentHôpital Necker Enfants Malades, APHPParisFrance
| | - Robin Lachmann
- C. Dent Adult Metabolic UnitNational Hospital for Neurology and NeurosurgeryLondonUK
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Vaccaro FA, Drennan CL. The role of nucleoside triphosphate hydrolase metallochaperones in making metalloenzymes. Metallomics 2022; 14:6575898. [PMID: 35485745 PMCID: PMC9164220 DOI: 10.1093/mtomcs/mfac030] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 04/07/2022] [Indexed: 11/13/2022]
Abstract
Metalloenzymes catalyze a diverse set of challenging chemical reactions that are essential for life. These metalloenzymes rely on a wide range of metallocofactors, from single metal ions to complicated metallic clusters. Incorporation of metal ions and metallocofactors into apo-proteins often requires the assistance of proteins known as metallochaperones. Nucleoside triphosphate hydrolases (NTPases) are one important class of metallochaperones and are found widely distributed throughout the domains of life. These proteins use the binding and hydrolysis of nucleoside triphosphates, either adenosine triphosphate (ATP) or guanosine triphosphate (GTP), to carry out highly specific and regulated roles in the process of metalloenzyme maturation. Here, we review recent literature on NTPase metallochaperones and describe the current mechanistic proposals and available structural data. By using representative examples from each type of NTPase, we also illustrate the challenges in studying these complicated systems. We highlight open questions in the field and suggest future directions. This minireview is part of a special collection of articles in memory of Professor Deborah Zamble, a leader in the field of nickel biochemistry.
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Affiliation(s)
- Francesca A Vaccaro
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, USA
| | - Catherine L Drennan
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, USA.,Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, USA.,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, USA
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11
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Li Z, Gouda H, Pillay S, Yaw M, Ruetz M, Banerjee R. The human B 12 trafficking chaperones: CblA, ATR, CblC and CblD. Methods Enzymol 2022; 668:137-156. [PMID: 35589192 PMCID: PMC9418966 DOI: 10.1016/bs.mie.2021.12.009] [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] [Indexed: 11/29/2022]
Abstract
Mammals rely on an elaborate intracellular trafficking pathway for processing and delivering vitamin B12 to two client enzymes. CblC (also known as MMACHC) is postulated to receive the cofactor as it enters the cytoplasm and converts varied B12 derivatives to a common cob(II)alamin intermediate. CblD (or MMADHC) reacts with CblC-bound cob(II)alamin forming an interprotein thiolato-cobalt coordination complex and, by a mechanism that remains to be elucidated, transfers the cofactor to methionine synthase. In the mitochondrion, CblB (also known as MMAB or adenosyltransferase) synthesizes AdoCbl from cob(II)alamin and ATP in the presence of an electron donor. CblA (or MMAA), a GTPase, gates cofactor loading from CblB to methylmalonyl-CoA mutase and off-loading of cob(II)alamin in the reverse direction. This chapter focuses on assays for measuring the activities of the four B12 chaperones CblA-D.
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Affiliation(s)
- Zhu Li
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Harsha Gouda
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Shubhadra Pillay
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Madeline Yaw
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Markus Ruetz
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Ruma Banerjee
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, United States
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12
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Banerjee R, Gouda H, Pillay S. Redox-Linked Coordination Chemistry Directs Vitamin B 12 Trafficking. Acc Chem Res 2021; 54:2003-2013. [PMID: 33797888 DOI: 10.1021/acs.accounts.1c00083] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Metals are partners for an estimated one-third of the proteome and vary in complexity from mononuclear centers to organometallic cofactors. Vitamin B12 or cobalamin represents the epitome of this complexity and is the product of an assembly line comprising some 30 enzymes. Unable to biosynthesize cobalamin, mammals rely on dietary provision of this essential cofactor, which is needed by just two enzymes, one each in the cytoplasm (methionine synthase) and the mitochondrion (methylmalonyl-CoA mutase). Brilliant clinical genetics studies on patients with inborn errors of cobalamin metabolism spanning several decades had identified at least seven genetic loci in addition to the two encoding B12 enzymes. While cells are known to house a cadre of chaperones dedicated to metal trafficking pathways that contain metal reactivity and confer targeting specificity, the seemingly supernumerary chaperones in the B12 pathway had raised obvious questions as to the rationale for their existence.With the discovery of the genes underlying cobalamin disorders, our laboratory has been at the forefront of ascribing functions to B12 chaperones and elucidating the intricate redox-linked coordination chemistry and protein-linked cofactor conformational dynamics that orchestrate the processing and translocation of cargo along the trafficking pathway. These studies have uncovered novel chemistry that exploits the innate chemical versatility of alkylcobalamins, i.e., the ability to form and dismantle the cobalt-carbon bond using homolytic or heterolytic chemistry. In addition, they have revealed the practical utility of the dimethylbenzimidazole tail, an appendage unique to cobalamins and absent in the structural cousins, porphyrin, chlorin, and corphin, as an instrument for facilitating cofactor transfer between active sites.In this Account, we navigate the chemistry of the B12 trafficking pathway from its point of entry into cells, through lysosomes, and into the cytoplasm, where incoming cobalamin derivatives with a diversity of upper ligands are denuded by the β-ligand transferase activity of CblC to the common cob(II)alamin intermediate. The broad reaction and lax substrate specificity of CblC also enables conversion of cyanocobalamin (technically, vitamin B12, i.e., the form of the cofactor in one-a-day supplements), to cob(II)alamin. CblD then hitches up with CblC via a unique Co-sulfur bond to cob(II)alamin at a bifurcation point, leading to the cytoplasmic methylcobalamin or mitochondrial 5'-deoxyadenosylcobalamin branch. Mutations at loci upstream of the junction point typically affect both branches, leading to homocystinuria and methylmalonic aciduria, whereas mutations in downstream loci lead to one or the other disease. Elucidation of the biochemical penalties associated with individual mutations is providing molecular insights into the clinical data and, in some instances, identifying which cobalamin derivative(s) might be therapeutically beneficial.Our studies on B12 trafficking are revealing strategies for cofactor sequestration and mobilization from low- to high-affinity and low- to high-coordination-number sites, which in turn are regulated by protein dynamics that constructs ergonomic cofactor binding pockets. While these B12 lessons might be broadly relevant to other metal trafficking pathways, much remains to be learned. This Account concludes by identifying some of the major gaps and challenges that are needed to complete our understanding of B12 trafficking.
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Affiliation(s)
- Ruma Banerjee
- Department of Biological Chemistry, Michigan Medicine, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Harsha Gouda
- Department of Biological Chemistry, Michigan Medicine, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Shubhadra Pillay
- Department of Biological Chemistry, Michigan Medicine, University of Michigan, Ann Arbor, Michigan 48109, United States
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13
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Osman D, Cooke A, Young TR, Deery E, Robinson NJ, Warren MJ. The requirement for cobalt in vitamin B 12: A paradigm for protein metalation. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2021; 1868:118896. [PMID: 33096143 PMCID: PMC7689651 DOI: 10.1016/j.bbamcr.2020.118896] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 10/13/2020] [Accepted: 10/14/2020] [Indexed: 12/20/2022]
Abstract
Vitamin B12, cobalamin, is a cobalt-containing ring-contracted modified tetrapyrrole that represents one of the most complex small molecules made by nature. In prokaryotes it is utilised as a cofactor, coenzyme, light sensor and gene regulator yet has a restricted role in assisting only two enzymes within specific eukaryotes including mammals. This deployment disparity is reflected in another unique attribute of vitamin B12 in that its biosynthesis is limited to only certain prokaryotes, with synthesisers pivotal in establishing mutualistic microbial communities. The core component of cobalamin is the corrin macrocycle that acts as the main ligand for the cobalt. Within this review we investigate why cobalt is paired specifically with the corrin ring, how cobalt is inserted during the biosynthetic process, how cobalt is made available within the cell and explore the cellular control of cobalt and cobalamin levels. The partitioning of cobalt for cobalamin biosynthesis exemplifies how cells assist metalation.
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Affiliation(s)
- Deenah Osman
- Department of Biosciences, Durham University, Durham DH1 3LE, UK; Department of Chemistry, Durham University, Durham DH1 3LE, UK.
| | - Anastasia Cooke
- School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK.
| | - Tessa R Young
- Department of Biosciences, Durham University, Durham DH1 3LE, UK; Department of Chemistry, Durham University, Durham DH1 3LE, UK.
| | - Evelyne Deery
- School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK.
| | - Nigel J Robinson
- Department of Biosciences, Durham University, Durham DH1 3LE, UK; Department of Chemistry, Durham University, Durham DH1 3LE, UK.
| | - Martin J Warren
- School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK; Quadram Institute Bioscience, Norwich Research Park, Norwich NR4 7UQ, UK; Biomedical Research Centre, University of East Anglia, Norwich NR4 7TJ, UK.
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14
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Krishnan A, Burroughs AM, Iyer LM, Aravind L. Comprehensive classification of ABC ATPases and their functional radiation in nucleoprotein dynamics and biological conflict systems. Nucleic Acids Res 2020; 48:10045-10075. [PMID: 32894288 DOI: 10.1093/nar/gkaa726] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/17/2020] [Accepted: 08/20/2020] [Indexed: 12/13/2022] Open
Abstract
ABC ATPases form one of the largest clades of P-loop NTPase fold enzymes that catalyze ATP-hydrolysis and utilize its free energy for a staggering range of functions from transport to nucleoprotein dynamics. Using sensitive sequence and structure analysis with comparative genomics, for the first time we provide a comprehensive classification of the ABC ATPase superfamily. ABC ATPases developed structural hallmarks that unambiguously distinguish them from other P-loop NTPases such as an alternative to arginine-finger-based catalysis. At least five and up to eight distinct clades of ABC ATPases are reconstructed as being present in the last universal common ancestor. They underwent distinct phases of structural innovation with the emergence of inserts constituting conserved binding interfaces for proteins or nucleic acids and the adoption of a unique dimeric toroidal configuration for DNA-threading. Specifically, several clades have also extensively radiated in counter-invader conflict systems where they serve as nodal nucleotide-dependent sensory and energetic components regulating a diversity of effectors (including some previously unrecognized) acting independently or together with restriction-modification systems. We present a unified mechanism for ABC ATPase function across disparate systems like RNA editing, translation, metabolism, DNA repair, and biological conflicts, and some unexpected recruitments, such as MutS ATPases in secondary metabolism.
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Affiliation(s)
- Arunkumar Krishnan
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - A Maxwell Burroughs
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Lakshminarayan M Iyer
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - L Aravind
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
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15
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Ruetz M, Campanello GC, McDevitt L, Yokom AL, Yadav PK, Watkins D, Rosenblatt DS, Ohi MD, Southworth DR, Banerjee R. Allosteric Regulation of Oligomerization by a B 12 Trafficking G-Protein Is Corrupted in Methylmalonic Aciduria. Cell Chem Biol 2019; 26:960-969.e4. [PMID: 31056463 DOI: 10.1016/j.chembiol.2019.03.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 03/07/2019] [Accepted: 03/25/2019] [Indexed: 10/26/2022]
Abstract
Allosteric regulation of methylmalonyl-CoA mutase (MCM) by the G-protein chaperone CblA is transduced via three "switch" elements that gate the movement of the B12 cofactor to and from MCM. Mutations in CblA and MCM cause hereditary methylmalonic aciduria. Unlike the bacterial orthologs used previously to model disease-causing mutations, human MCM and CblA exhibit a complex pattern of regulation that involves interconverting oligomers, which are differentially sensitive to the presence of GTP versus GDP. Patient mutations in the switch III region of CblA perturb the nucleotide-sensitive distribution of the oligomeric complexes with MCM, leading to loss of regulated movement of B12 to and/or from MCM and explain the molecular mechanism of the resulting disease.
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Affiliation(s)
- Markus Ruetz
- Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, MI, USA
| | - Gregory C Campanello
- Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, MI, USA
| | - Liam McDevitt
- Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, MI, USA
| | - Adam L Yokom
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Pramod K Yadav
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - David Watkins
- Department of Human Genetics, McGill University, Montreal, QC H3A 1B1, Canada
| | - David S Rosenblatt
- Department of Human Genetics, McGill University, Montreal, QC H3A 1B1, Canada
| | - Melanie D Ohi
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Daniel R Southworth
- Department of Biochemistry and Biophysics, Institute for Neurodegenerative Diseases, University of California-San Francisco, San Francisco, CA 94158, USA
| | - Ruma Banerjee
- Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, MI, USA.
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16
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Campanello GC, Lofgren M, Yokom AL, Southworth DR, Banerjee R. Switch I-dependent allosteric signaling in a G-protein chaperone-B 12 enzyme complex. J Biol Chem 2017; 292:17617-17625. [PMID: 28882898 DOI: 10.1074/jbc.m117.786095] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 08/14/2017] [Indexed: 11/06/2022] Open
Abstract
G-proteins regulate various processes ranging from DNA replication and protein synthesis to cytoskeletal dynamics and cofactor assimilation and serve as models for uncovering strategies deployed for allosteric signal transduction. MeaB is a multifunctional G-protein chaperone, which gates loading of the active 5'-deoxyadenosylcobalamin cofactor onto methylmalonyl-CoA mutase (MCM) and precludes loading of inactive cofactor forms. MeaB also safeguards MCM, which uses radical chemistry, against inactivation and rescues MCM inactivated during catalytic turnover by using the GTP-binding energy to offload inactive cofactor. The conserved switch I and II signaling motifs used by G-proteins are predicted to mediate allosteric regulation in response to nucleotide binding and hydrolysis in MeaB. Herein, we targeted conserved residues in the MeaB switch I motif to interrogate the function of this loop. Unexpectedly, the switch I mutations had only modest effects on GTP binding and on GTPase activity and did not perturb stability of the MCM-MeaB complex. However, these mutations disrupted multiple MeaB chaperone functions, including cofactor editing, loading, and offloading. Hence, although residues in the switch I motif are not essential for catalysis, they are important for allosteric regulation. Furthermore, single-particle EM analysis revealed, for the first time, the overall architecture of the MCM-MeaB complex, which exhibits a 2:1 stoichiometry. These EM studies also demonstrate that the complex exhibits considerable conformational flexibility. In conclusion, the switch I element does not significantly stabilize the MCM-MeaB complex or influence the affinity of MeaB for GTP but is required for transducing signals between MeaB and MCM.
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Affiliation(s)
- Gregory C Campanello
- From the Departments of Biological Chemistry, University of Michigan Medical Center, and
| | - Michael Lofgren
- From the Departments of Biological Chemistry, University of Michigan Medical Center, and
| | - Adam L Yokom
- From the Departments of Biological Chemistry, University of Michigan Medical Center, and.,the Department of Biological Chemistry and.,the Graduate Program in Chemical Biology, Life Sciences Institute, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600
| | - Daniel R Southworth
- From the Departments of Biological Chemistry, University of Michigan Medical Center, and.,the Department of Biological Chemistry and
| | - Ruma Banerjee
- From the Departments of Biological Chemistry, University of Michigan Medical Center, and
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17
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Plessl T, Bürer C, Lutz S, Yue WW, Baumgartner MR, Froese DS. Protein destabilization and loss of protein‐protein interaction are fundamental mechanisms in
cblA
‐type methylmalonic aciduria. Hum Mutat 2017; 38:988-1001. [DOI: 10.1002/humu.23251] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 04/12/2017] [Accepted: 05/06/2017] [Indexed: 12/31/2022]
Affiliation(s)
- Tanja Plessl
- Division of Metabolism and Children's Research CenterUniversity Children'sHospital Zurich Switzerland
- Zurich Center for Integrative Human PhysiologyUniversity of Zurich Switzerland
| | - Céline Bürer
- Division of Metabolism and Children's Research CenterUniversity Children'sHospital Zurich Switzerland
| | - Seraina Lutz
- Division of Metabolism and Children's Research CenterUniversity Children'sHospital Zurich Switzerland
| | - Wyatt W. Yue
- Structural Genomics ConsortiumNuffield Department of Clinical MedicineUniversity of Oxford Oxford United Kingdom
| | - Matthias R. Baumgartner
- Division of Metabolism and Children's Research CenterUniversity Children'sHospital Zurich Switzerland
- Zurich Center for Integrative Human PhysiologyUniversity of Zurich Switzerland
- radiz – Rare Disease Initiative ZurichClinical Research Priority Program for Rare DiseasesUniversity of ZurichZurich Switzerland
| | - D. Sean Froese
- Division of Metabolism and Children's Research CenterUniversity Children'sHospital Zurich Switzerland
- radiz – Rare Disease Initiative ZurichClinical Research Priority Program for Rare DiseasesUniversity of ZurichZurich Switzerland
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18
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Li Z, Kitanishi K, Twahir UT, Cracan V, Chapman D, Warncke K, Banerjee R. Cofactor Editing by the G-protein Metallochaperone Domain Regulates the Radical B 12 Enzyme IcmF. J Biol Chem 2017; 292:3977-3987. [PMID: 28130442 DOI: 10.1074/jbc.m117.775957] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Indexed: 11/06/2022] Open
Abstract
IcmF is a 5'-deoxyadenosylcobalamin (AdoCbl)-dependent enzyme that catalyzes the carbon skeleton rearrangement of isobutyryl-CoA to butyryl-CoA. It is a bifunctional protein resulting from the fusion of a G-protein chaperone with GTPase activity and the cofactor- and substrate-binding mutase domains with isomerase activity. IcmF is prone to inactivation during catalytic turnover, thus setting up its dependence on a cofactor repair system. Herein, we demonstrate that the GTPase activity of IcmF powers the ejection of the inactive cob(II)alamin cofactor and requires the presence of an acceptor protein, adenosyltransferase, for receiving it. Adenosyltransferase in turn converts cob(II)alamin to AdoCbl in the presence of ATP and a reductant. The repaired cofactor is then reloaded onto IcmF in a GTPase-gated step. The mechanistic details of cofactor loading and offloading from the AdoCbl-dependent IcmF are distinct from those of the better characterized and homologous methylmalonyl-CoA mutase/G-protein chaperone system.
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Affiliation(s)
- Zhu Li
- From the Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600 and
| | - Kenichi Kitanishi
- From the Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600 and
| | - Umar T Twahir
- the Department of Physics, Emory University, Atlanta, Georgia 30322-2430
| | - Valentin Cracan
- From the Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600 and
| | - Derrell Chapman
- From the Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600 and
| | - Kurt Warncke
- the Department of Physics, Emory University, Atlanta, Georgia 30322-2430
| | - Ruma Banerjee
- From the Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600 and
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19
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Askenasy I, Pennington JM, Tao Y, Marshall AG, Young NL, Shang W, Stroupe ME. The N-terminal Domain of Escherichia coli Assimilatory NADPH-Sulfite Reductase Hemoprotein Is an Oligomerization Domain That Mediates Holoenzyme Assembly. J Biol Chem 2015; 290:19319-33. [PMID: 26088143 PMCID: PMC4521050 DOI: 10.1074/jbc.m115.662379] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Revised: 06/05/2015] [Indexed: 11/06/2022] Open
Abstract
Assimilatory NADPH-sulfite reductase (SiR) from Escherichia coli is a structurally complex oxidoreductase that catalyzes the six-electron reduction of sulfite to sulfide. Two subunits, one a flavin-binding flavoprotein (SiRFP, the α subunit) and the other an iron-containing hemoprotein (SiRHP, the β subunit), assemble to make a holoenzyme of about 800 kDa. How the two subunits assemble is not known. The iron-rich cofactors in SiRHP are unique because they are a covalent arrangement of a Fe4S4 cluster attached through a cysteine ligand to an iron-containing porphyrinoid called siroheme. The link between cofactor biogenesis and SiR stability is also ill-defined. By use of hydrogen/deuterium exchange and biochemical analysis, we show that the α8β4 SiR holoenzyme assembles through the N terminus of SiRHP and the NADPH binding domain of SiRFP. By use of small angle x-ray scattering, we explore the structure of the SiRHP N-terminal oligomerization domain. We also report a novel form of the hemoprotein that occurs in the absence of its cofactors. Apo-SiRHP forms a homotetramer, also dependent on its N terminus, that is unable to assemble with SiRFP. From these results, we propose that homotetramerization of apo-SiRHP serves as a quality control mechanism to prevent formation of inactive holoenzyme in the case of limiting cellular siroheme.
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Affiliation(s)
- Isabel Askenasy
- From the Department of Biological Science and Institute of Molecular Biophysics and
| | - Joseph M Pennington
- From the Department of Biological Science and Institute of Molecular Biophysics and
| | - Yeqing Tao
- the Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306
| | - Alan G Marshall
- the Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, the National High Magnetic Field Laboratory, Tallahassee, Florida 32310, and
| | - Nicolas L Young
- the National High Magnetic Field Laboratory, Tallahassee, Florida 32310, and
| | - Weifeng Shang
- the Center for Synchrotron Radiation Research and Instrumentation and Department of Biological and Chemical Sciences, Illinois Institute of Technology, Chicago, Illinois 60616
| | - M Elizabeth Stroupe
- From the Department of Biological Science and Institute of Molecular Biophysics and
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20
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Crystal structures of Mycobacterial MeaB and MMAA-like GTPases. ACTA ACUST UNITED AC 2015; 16:91-9. [PMID: 25832174 DOI: 10.1007/s10969-015-9197-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 03/14/2015] [Indexed: 10/23/2022]
Abstract
The methylmalonyl Co-A mutase-associated GTPase MeaB from Methylobacterium extorquens is involved in glyoxylate regulation and required for growth. In humans, mutations in the homolog methylmalonic aciduria associated protein (MMAA) cause methylmalonic aciduria, which is often fatal. The central role of MeaB from bacteria to humans suggests that MeaB is also important in other, pathogenic bacteria such as Mycobacterium tuberculosis. However, the identity of the mycobacterial MeaB homolog is presently unclear. Here, we identify the M. tuberculosis protein Rv1496 and its homologs in M. smegmatis and M. thermoresistibile as MeaB. The crystal structures of all three homologs are highly similar to MeaB and MMAA structures and reveal a characteristic three-domain homodimer with GDP bound in the G domain active site. A structure of Rv1496 obtained from a crystal grown in the presence of GTP exhibited electron density for GDP, suggesting GTPase activity. These structures identify the mycobacterial MeaB and provide a structural framework for therapeutic targeting of M. tuberculosis MeaB.
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21
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Visualization of a radical B12 enzyme with its G-protein chaperone. Proc Natl Acad Sci U S A 2015; 112:2419-24. [PMID: 25675500 DOI: 10.1073/pnas.1419582112] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
G-protein metallochaperones ensure fidelity during cofactor assembly for a variety of metalloproteins, including adenosylcobalamin (AdoCbl)-dependent methylmalonyl-CoA mutase and hydrogenase, and thus have both medical and biofuel development applications. Here, we present crystal structures of IcmF, a natural fusion protein of AdoCbl-dependent isobutyryl-CoA mutase and its corresponding G-protein chaperone, which reveal the molecular architecture of a G-protein metallochaperone in complex with its target protein. These structures show that conserved G-protein elements become ordered upon target protein association, creating the molecular pathways that both sense and report on the cofactor loading state. Structures determined of both apo- and holo-forms of IcmF depict both open and closed enzyme states, in which the cofactor-binding domain is alternatively positioned for cofactor loading and for catalysis. Notably, the G protein moves as a unit with the cofactor-binding domain, providing a visualization of how a chaperone assists in the sequestering of a precious cofactor inside an enzyme active site.
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22
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Deng S, Yuan P, Ji X, Shan D, Zhang X. Carbon nitride nanosheet-supported porphyrin: a new biomimetic catalyst for highly efficient bioanalysis. ACS APPLIED MATERIALS & INTERFACES 2015; 7:543-552. [PMID: 25495667 DOI: 10.1021/am506645h] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A highly efficient biomimetic catalyst was fabricated based on ultrathin carbon nitride nanosheets (C3N4)-supported cobalt(II) proto-porphyrin IX (CoPPIX). The periodical pyridinic nitrogen units in C3N4 backbone could serve as electron donors for great affinity with Co(2+) in PPIX, which resembled the local electronic structure as vitamin B12 and heme cofactor of hemoglobin. UV-vis kinetics and electrochemistry revealed its competitive (electro)catalysis with conventional peroxidase, while X-ray photoelectron spectroscopy and theoretical calculations suggest that the rehybridization of Co 3d with N orbitals from the backside can result in significant changes in enthalpy and charge density, which greatly promoted the activity of CoPPIX. The prepared nanocatalyst was further conjugated with streptavidin via multiple amines on the edge plane of C3N4 for facile tagging. Using biotinylated molecular beacon as the capture probe, a sensitive electrochemiluminescence-based DNA assay was developed via the electroreduction of H2O2 as the coreactant after the hairpin unfolded by the target, exhibiting linearity from 1.0 fM to 0.1 nM and a detection limit of 0.37 fM. Our results demonstrate a new paradigm to rationally design inexpensive and durable biomimics for electrochemiluminescence quenching strategy, showing great promise in bioanalytical applications.
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Affiliation(s)
- Shengyuan Deng
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology , Nanjing 210094, P. R. China
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23
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Cobalamin-dependent dehydratases and a deaminase: Radical catalysis and reactivating chaperones. Arch Biochem Biophys 2014; 544:40-57. [DOI: 10.1016/j.abb.2013.11.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Revised: 11/04/2013] [Accepted: 11/08/2013] [Indexed: 01/12/2023]
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24
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Mori K, Obayashi K, Hosokawa Y, Yamamoto A, Yano M, Yoshinaga T, Toraya T. Essential roles of nucleotide-switch and metal-coordinating residues for chaperone function of diol dehydratase-reactivase. Biochemistry 2013; 52:8677-86. [PMID: 24229359 DOI: 10.1021/bi401290j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Diol dehydratase-reactivase (DD-R) is a molecular chaperone that reactivates inactivated holodiol dehydratase (DD) by cofactor exchange. Its ADP-bound and ATP-bound forms are high-affinity and low-affinity forms for DD, respectively. Among DD-Rs mutated at the nucleotide-binding site, neither the Dα8N nor Dα413N mutant was effective as a reactivase. Although Dα413N showed ATPase activity, it did not mediate cyanocobalamin (CN-Cbl) release from the DD·CN-Cbl complex in the presence of ATP or ADP and formed a tight complex with apoDD even in the presence of ATP, suggesting the involvement of Aspα413 in the nucleotide switch. In contrast, Dα8N showed very low ATPase activity and did not mediate CN-Cbl release from the complex in the presence of ATP, but it did cause about 50% release in the presence of ADP. The complex formation of this mutant with DD was partially reversed by ATP, suggesting that Aspα8 is involved in the ATPase activity but only partially in the nucleotide switch. Among DD-Rs mutated at the Mg(2+)-binding site, only Eβ31Q was about 30% as active as wild-type DD-R and formed a tight complex with apoDD, indicating that the DD-R β subunit is not absolutely required for reactivation. If subunit swapping occurs between the DD-R β and DD β subunits, Gluβ97 of DD would coordinate to Mg(2+). The complex of Eβ97Q DD with CN-Cbl was not activated by wild-type DD-R. No complex was formed between this mutant and wild-type DD-R, indicating that the coordination of Gluβ97 to Mg(2+) is essential for subunit swapping and therefore for (re)activation.
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Affiliation(s)
- Koichi Mori
- Department of Bioscience and Biotechnology, Graduate School of Natural Science and Technology, Okayama University , Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
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25
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Lofgren M, Koutmos M, Banerjee R. Autoinhibition and signaling by the switch II motif in the G-protein chaperone of a radical B12 enzyme. J Biol Chem 2013; 288:30980-9. [PMID: 23996001 DOI: 10.1074/jbc.m113.499970] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
MeaB is an accessory GTPase protein involved in the assembly, protection, and reactivation of 5'-deoxyadenosyl cobalamin-dependent methylmalonyl-CoA mutase (MCM). Mutations in the human ortholog of MeaB result in methylmalonic aciduria, an inborn error of metabolism. G-proteins typically utilize conserved switch I and II motifs for signaling to effector proteins via conformational changes elicited by nucleotide binding and hydrolysis. Our recent discovery that MeaB utilizes an unusual switch III region for bidirectional signaling with MCM raised questions about the roles of the switch I and II motifs in MeaB. In this study, we addressed the functions of conserved switch II residues by performing alanine-scanning mutagenesis. Our results demonstrate that the GTPase activity of MeaB is autoinhibited by switch II and that this loop is important for coupling nucleotide-sensitive conformational changes in switch III to elicit the multiple chaperone functions of MeaB. Furthermore, we report the structure of MeaB·GDP crystallized in the presence of AlFx(-) to form the putative transition state analog, GDP·AlF4(-). The resulting crystal structure and its comparison with related G-proteins support the conclusion that the catalytic site of MeaB is incomplete in the absence of the GTPase-activating protein MCM and therefore unable to stabilize the transition state analog. Favoring an inactive conformation in the absence of the client MCM protein might represent a strategy for suppressing the intrinsic GTPase activity of MeaB in which the switch II loop plays an important role.
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Affiliation(s)
- Michael Lofgren
- From the Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600 and
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