1
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Chen D, Zhang X, Vorobieva AA, Tachibana R, Stein A, Jakob RP, Zou Z, Graf DA, Li A, Maier T, Correia BE, Ward TR. An evolved artificial radical cyclase enables the construction of bicyclic terpenoid scaffolds via an H-atom transfer pathway. Nat Chem 2024:10.1038/s41557-024-01562-5. [PMID: 39030420 DOI: 10.1038/s41557-024-01562-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 05/24/2024] [Indexed: 07/21/2024]
Abstract
While natural terpenoid cyclases generate complex terpenoid structures via cationic mechanisms, alternative radical cyclization pathways are underexplored. The metal-catalysed H-atom transfer reaction (M-HAT) offers an attractive means for hydrofunctionalizing olefins, providing access to terpenoid-like structures. Artificial metalloenzymes offer a promising strategy for introducing M-HAT reactivity into a protein scaffold. Here we report our efforts towards engineering an artificial radical cyclase (ARCase), resulting from anchoring a biotinylated [Co(Schiff-base)] cofactor within an engineered chimeric streptavidin. After two rounds of directed evolution, a double mutant catalyses a radical cyclization to afford bicyclic products with a cis-5-6-fused ring structure and up to 97% enantiomeric excess. The involvement of a histidine ligation to the Co cofactor is confirmed by crystallography. A time course experiment reveals a cascade reaction catalysed by the ARCase, combining a radical cyclization with a conjugate reduction. The ARCase exhibits tolerance towards variations in the dienone substrate, highlighting its potential to access terpenoid scaffolds.
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Affiliation(s)
- Dongping Chen
- Department of Chemistry, University of Basel, Basel, Switzerland
- National Center of Competence in Research 'Catalysis', ETH Zurich, Zurich, Switzerland
- National Center of Competence in Research 'Molecular Systems Engineering', Basel, Switzerland
| | - Xiang Zhang
- Department of Chemistry, University of Basel, Basel, Switzerland
- National Center of Competence in Research 'Catalysis', ETH Zurich, Zurich, Switzerland
- National Center of Competence in Research 'Molecular Systems Engineering', Basel, Switzerland
| | - Anastassia Andreevna Vorobieva
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
- VIB-VUB Center for Structural Biology, Brussels, Belgium
| | - Ryo Tachibana
- Department of Chemistry, University of Basel, Basel, Switzerland
- National Center of Competence in Research 'Catalysis', ETH Zurich, Zurich, Switzerland
| | - Alina Stein
- National Center of Competence in Research 'Molecular Systems Engineering', Basel, Switzerland
| | | | - Zhi Zou
- Department of Chemistry, University of Basel, Basel, Switzerland
- National Center of Competence in Research 'Molecular Systems Engineering', Basel, Switzerland
| | - Damian Alexander Graf
- Department of Chemistry, University of Basel, Basel, Switzerland
- National Center of Competence in Research 'Molecular Systems Engineering', Basel, Switzerland
| | - Ang Li
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Timm Maier
- Biozentrum, University of Basel, Basel, Switzerland
| | - Bruno E Correia
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
| | - Thomas R Ward
- Department of Chemistry, University of Basel, Basel, Switzerland.
- National Center of Competence in Research 'Catalysis', ETH Zurich, Zurich, Switzerland.
- National Center of Competence in Research 'Molecular Systems Engineering', Basel, Switzerland.
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2
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Elmendorf LD, Brunold TC. Electronic structure studies of free and enzyme-bound B 12 species by magnetic circular dichroism and complementary spectroscopic techniques. Methods Enzymol 2022; 669:333-365. [PMID: 35644179 DOI: 10.1016/bs.mie.2022.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Electronic absorption (Abs) and circular dichroism (CD) spectroscopic techniques have been used successfully for over half a century in studies of free and enzyme-bound B12 species. More recently, magnetic circular dichroism (MCD) spectroscopy and other complementary techniques have provided an increasingly detailed understanding of the electronic structure of cobalamins. While CD spectroscopy measures the difference in the absorption of left- and right-circularly polarized light, MCD spectroscopy adds the application of a magnetic field parallel to the direction of light propagation. Transitions that are formally forbidden according to the Abs and CD selection rules, such as ligand field (or d→d) transitions, can gain MCD intensity through spin-orbit coupling. As such, MCD spectroscopy provides a uniquely sensitive probe of the different binding modes, Co oxidation states, and axial ligand environments of B12 species in enzyme active sites, and thus the distinct reactivities displayed by these species. This chapter summarizes representative MCD studies of free and enzyme-bound B12 species, including those present in adenosyltransferases, isomerases, and reductive dehalogenases. Complementary spectroscopic and computational data are also presented and discussed where appropriate.
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Affiliation(s)
- Laura D Elmendorf
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, United States
| | - Thomas C Brunold
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, United States.
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3
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Chen JR, Ke TX, Frey PA, Ke SC. Electron Spin Echo Envelope Modulation Spectroscopy Reveals How Adenosylcobalamin-Dependent Lysine 5,6-Aminomutase Positions the Radical Pair Intermediates and Modulates Their Stabilities for Efficient Catalysis. ACS Catal 2021. [DOI: 10.1021/acscatal.1c03182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jun-Ru Chen
- Physics Department, National Dong Hwa University, Hualien 974301, Taiwan
| | - Ting-Xi Ke
- Physics Department, National Dong Hwa University, Hualien 974301, Taiwan
| | - Perry A. Frey
- Department of Biochemistry, University of Wisconsin−Madison, Madison, Wisconsin 53726, United States
| | - Shyue-Chu Ke
- Physics Department, National Dong Hwa University, Hualien 974301, Taiwan
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4
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Reaction kinetic analysis of the 3-hydroxypropionate/4-hydroxybutyrate CO 2 fixation cycle in extremely thermoacidophilic archaea. Metab Eng 2016; 38:446-463. [PMID: 27771364 DOI: 10.1016/j.ymben.2016.10.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 09/07/2016] [Accepted: 10/17/2016] [Indexed: 12/21/2022]
Abstract
The 3-hydroxypropionate/4-hydroxybutyrate (3HP/4HB) cycle fixes CO2 in extremely thermoacidophilic archaea and holds promise for metabolic engineering because of its thermostability and potentially rapid pathway kinetics. A reaction kinetics model was developed to examine the biological and biotechnological attributes of the 3HP/4HB cycle as it operates in Metallosphaera sedula, based on previous information as well as on kinetic parameters determined here for recombinant versions of five of the cycle enzymes (malonyl-CoA/succinyl-CoA reductase, 3-hydroxypropionyl-CoA synthetase, 3-hydroxypropionyl-CoA dehydratase, acryloyl-CoA reductase, and succinic semialdehyde reductase). The model correctly predicted previously observed features of the cycle: the 35-65% split of carbon flux through the acetyl-CoA and succinate branches, the high abundance and relative ratio of acetyl-CoA/propionyl-CoA carboxylase (ACC) and MCR, and the significance of ACC and hydroxybutyryl-CoA synthetase (HBCS) as regulated control points for the cycle. The model was then used to assess metabolic engineering strategies for incorporating CO2 into chemical intermediates and products of biotechnological importance: acetyl-CoA, succinate, and 3-hydroxypropionate.
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5
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Conrad KS, Jordan CD, Brown KL, Brunold TC. Spectroscopic and Computational Studies of Cobalamin Species with Variable Lower Axial Ligation: Implications for the Mechanism of Co–C Bond Activation by Class I Cobalamin-Dependent Isomerases. Inorg Chem 2015; 54:3736-47. [DOI: 10.1021/ic502665x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Karen S. Conrad
- Department
of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Christopher D. Jordan
- Department
of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Kenneth L. Brown
- Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, United States
| | - Thomas C. Brunold
- Department
of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
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6
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EPR and XANES studies of anaerobic photolysis of iso-propilpyridinecobaloxime: Elucidation of the reactivity of the Co(II) primary product. J Organomet Chem 2014. [DOI: 10.1016/j.jorganchem.2014.01.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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7
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Takahashi-Iñiguez T, García-Hernandez E, Arreguín-Espinosa R, Flores ME. Role of vitamin B12 on methylmalonyl-CoA mutase activity. J Zhejiang Univ Sci B 2012; 13:423-37. [PMID: 22661206 DOI: 10.1631/jzus.b1100329] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Vitamin B(12) is an organometallic compound with important metabolic derivatives that act as cofactors of certain enzymes, which have been grouped into three subfamilies depending on their cofactors. Among them, methylmalonyl-CoA mutase (MCM) has been extensively studied. This enzyme catalyzes the reversible isomerization of L-methylmalonyl-CoA to succinyl-CoA using adenosylcobalamin (AdoCbl) as a cofactor participating in the generation of radicals that allow isomerization of the substrate. The crystal structure of MCM determined in Propionibacterium freudenreichii var. shermanii has helped to elucidate the role of this cofactor AdoCbl in the reaction to specify the mechanism by which radicals are generated from the coenzyme and to clarify the interactions between the enzyme, coenzyme, and substrate. The existence of human methylmalonic acidemia (MMA) due to the presence of mutations in MCM shows the importance of its role in metabolism. The recent crystallization of the human MCM has shown that despite being similar to the bacterial protein, there are significant differences in the structural organization of the two proteins. Recent studies have identified the involvement of an accessory protein called MMAA, which interacts with MCM to prevent MCM's inactivation or acts as a chaperone to promote regeneration of inactivated enzyme. The interdisciplinary studies using this protein as a model in different organisms have helped to elucidate the mechanism of action of this isomerase, the impact of mutations at a functional level and their repercussion in the development and progression of MMA in humans. It is still necessary to study the mechanisms involved in more detail using new methods.
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Affiliation(s)
- Tóshiko Takahashi-Iñiguez
- Department of Molecular Biology and Biotechnology, Institute of Biomedical Research, National Autonomous University of Mexico, D.F. 04510, Mexico.
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8
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Bucher D, Sandala GM, Durbeej B, Radom L, Smith DM. The Elusive 5′-Deoxyadenosyl Radical in Coenzyme-B12-Mediated Reactions. J Am Chem Soc 2012; 134:1591-9. [DOI: 10.1021/ja207809b] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Denis Bucher
- School of Chemistry and ARC Centre of Excellence
for Free Radical Chemistry
and Biotechnology, University of Sydney, Sydney, NSW 2006, Australia
| | - Gregory M. Sandala
- School of Chemistry and ARC Centre of Excellence
for Free Radical Chemistry
and Biotechnology, University of Sydney, Sydney, NSW 2006, Australia
- Division of Organic
Chemistry and Biochemistry, Ruđer Bošković Institute, 10002 Zagreb, Croatia
| | - Bo Durbeej
- Division of Computational
Physics, IFM Theory and Modelling, Linköping University, SE-581 83 Linköping, Sweden
| | - Leo Radom
- School of Chemistry and ARC Centre of Excellence
for Free Radical Chemistry
and Biotechnology, University of Sydney, Sydney, NSW 2006, Australia
| | - David M. Smith
- Division of Organic
Chemistry and Biochemistry, Ruđer Bošković Institute, 10002 Zagreb, Croatia
- Computer-Chemie-Centrum, University of Erlangen-Nürnberg, 91052 Erlangen, Germany
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9
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Froese DS, Zhang J, Healy S, Gravel RA. Mechanism of vitamin B12-responsiveness in cblC methylmalonic aciduria with homocystinuria. Mol Genet Metab 2009; 98:338-43. [PMID: 19700356 DOI: 10.1016/j.ymgme.2009.07.014] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2009] [Revised: 07/22/2009] [Accepted: 07/22/2009] [Indexed: 11/28/2022]
Abstract
Patients with the cblC vitamin B(12) (cobalamin, cbl) disorder are defective in the intracellular synthesis of adenosylcobalamin and methylcobalamin and have combined homocystinuria and methylmalonic aciduria. While other vitamin B(12) disorders are treatable with high dose cyanocobalamin (CNCbl) or hydroxocobalamin (OHCbl), cblC patients respond well to OHCbl but not to CNCbl. Patient mutations were introduced into recombinant MMACHC (cblC) protein and the binding of CNCbl and OHCbl was examined. Three mutations were analyzed: G147D, associated with early onset, vitamin B(12) unresponsive disease; R161Q, associated with late onset disease that is highly responsive to OHCbl; and H122A, selected to test the hypothesis that H122 is central to a proposed vitamin B(12) binding motif on MMACHC. We report here that wild-type MMACHC binds both OHCbl and CNCbl with similar, tight affinity (K(d)=5.7 microM). We also report that MMACHC binds CNCbl in the base-off form, with the dimethylbenzimidazole (DMB) base of cobalamin displaced from coordination with the cobalt. In this form, wild-type MMACHC is able to reductively decyanate CNCbl to cob(II)alamin requiring only the presence of NADPH and FAD. We demonstrate that MMACHC with the G147D mutation is unable to bind either CNCbl or OHCbl, providing a straight forward explanation for the absence of response to either vitamin form. However, we show that MMACHC containing the R161Q mutation binds OHCbl with wild-type affinity, but is disturbed in binding CNCbl and has impaired decyanation. Finally, we show that H122A has reduced binding, but like R161Q, it binds OHCbl more tightly than CNCbl, suggesting that this histidine is not absolutely required for binding. These studies suggest that the ability of mutant MMACHC to respond to vitamin therapy depends on its ability to bind the vitamin with significant affinity, and for CNCbl, also on its ability to bind in the base-off form to facilitate reductive decyanation. These studies emphasize the continued use of OHCbl with cblC patients for maximum therapeutic effect.
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Affiliation(s)
- D S Froese
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alta., Canada.
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10
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Gomes J, Castro BD, Rangel M. EPR Study of the Photolysis of Methyl- and Adenosylcobinamides in the Presence of Phosphine and Pyridine Bases. Evidence for the Need of a Judicious Choice of Irradiation Temperature and Solvent to Assess Ligand Binding. Organometallics 2008. [DOI: 10.1021/om700837d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- João Gomes
- Requimte, Departamento de Química, Faculdade de Ciências, Universidade do Porto, 4160-007 Porto, Portugal, and Requimte, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, 4099-003 Porto, Portugal
| | - Baltazar de Castro
- Requimte, Departamento de Química, Faculdade de Ciências, Universidade do Porto, 4160-007 Porto, Portugal, and Requimte, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, 4099-003 Porto, Portugal
| | - Maria Rangel
- Requimte, Departamento de Química, Faculdade de Ciências, Universidade do Porto, 4160-007 Porto, Portugal, and Requimte, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, 4099-003 Porto, Portugal
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11
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Buckel W, Kratky C, Golding BT. Stabilisation of methylene radicals by cob(II)alamin in coenzyme B12 dependent mutases. Chemistry 2007; 12:352-62. [PMID: 16304645 DOI: 10.1002/chem.200501074] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Coenzyme B12 initiates radical chemistry in two types of enzymatic reactions, the irreversible eliminases (e.g., diol dehydratases) and the reversible mutases (e.g., methylmalonyl-CoA mutase). Whereas eliminases that use radical generators other than coenzyme B12 are known, no alternative coenzyme B12 independent mutases have been detected for substrates in which a methyl group is reversibly converted to a methylene radical. We predict that such mutases do not exist. However, coenzyme B12 independent pathways have been detected that circumvent the need for glutamate, beta-lysine or methylmalonyl-CoA mutases by proceeding via different intermediates. In humans the methylcitrate cycle, which is ostensibly an alternative to the coenzyme B12 dependent methylmalonyl-CoA pathway for propionate oxidation, is not used because it would interfere with the Krebs cycle and thereby compromise the high-energy requirement of the nervous system. In the diol dehydratases the 5'-deoxyadenosyl radical generated by homolysis of the carbon-cobalt bond of coenzyme B12 moves about 10 A away from the cobalt atom in cob(II)alamin. The substrate and product radicals are generated at a similar distance from cob(II)alamin, which acts solely as spectator of the catalysis. In glutamate and methylmalonyl-CoA mutases the 5'-deoxyadenosyl radical remains within 3-4 A of the cobalt atom, with the substrate and product radicals approximately 3 A further away. It is suggested that cob(II)alamin acts as a conductor by stabilising both the 5'-deoxyadenosyl radical and the product-related methylene radicals.
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Affiliation(s)
- Wolfgang Buckel
- Fachbereich Biologie, Philipps-Universität, 35032 Marburg, Germany.
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12
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Hannibal L, Bunge SD, van Eldik R, Jacobsen DW, Kratky C, Gruber K, Brasch NE. X-ray structural characterization of imidazolylcobalamin and histidinylcobalamin: cobalamin models for aquacobalamin bound to the B12 transporter protein transcobalamin. Inorg Chem 2007; 46:3613-8. [PMID: 17407285 PMCID: PMC2755209 DOI: 10.1021/ic070022n] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The X-ray structures of imidazolylcobalamin (ImCbl) and histidinylcobalamin (HisCbl) are reported. These structures are of interest given that the recent structures of human and bovine transcobalamin prepared in their holo forms from aquacobalamin show a histidine residue of the metalloprotein bound at the beta-axial site of the cobalamin (Wuerges, J. et al. Proc. Natl. Acad. Sci. U.S.A. 2006, 103, 4386-4391). The beta-axial Co-N bond distances for ImCbl and HisCbl are 1.94(1) and 1.951(7) A, respectively. The alpha-axial Co-N bond distances to the 5,6-dimethylbenzimidazole are 2.01(1) and 1.979(8) A for ImCbl and HisCbl, respectively, and are typical for cobalamins with weak sigma-donor ligands at the beta-axial site. The corrin fold angles of 11.8(3) degrees (ImCbl) and 12.0(3) degrees (HisCbl) are smaller than those typically observed for cobalamins.
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Affiliation(s)
- Luciana Hannibal
- Department of Chemistry, Kent State University, Kent, Ohio 44242
- School of Biomedical Sciences, Kent State University, Kent, Ohio 44242
- Department of Cell Biology, Lerner Research Institute, The Cleveland Clinic, Cleveland, Ohio 44195
| | - Scott D. Bunge
- Department of Chemistry, Kent State University, Kent, Ohio 44242
| | - Rudi van Eldik
- Institute for Inorganic Chemistry, University of Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Donald W. Jacobsen
- School of Biomedical Sciences, Kent State University, Kent, Ohio 44242
- Department of Cell Biology, Lerner Research Institute, The Cleveland Clinic, Cleveland, Ohio 44195
| | - Christoph Kratky
- Institute of Chemistry, University of Graz, A-8010 Graz, Austria
| | - Karl Gruber
- Institute of Chemistry, University of Graz, A-8010 Graz, Austria
| | - Nicola E. Brasch
- Department of Chemistry, Kent State University, Kent, Ohio 44242
- School of Biomedical Sciences, Kent State University, Kent, Ohio 44242
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13
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Pierik AJ, Ciceri D, Lopez RF, Kroll F, Bröker G, Beatrix B, Buckel W, Golding BT. Searching for intermediates in the carbon skeleton rearrangement of 2-methyleneglutarate to (R)-3-methylitaconate catalyzed by coenzyme B12-dependent 2-methyleneglutarate mutase from Eubacterium barkeri. Biochemistry 2005; 44:10541-51. [PMID: 16060663 DOI: 10.1021/bi050049n] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Coenzyme B(12)-dependent 2-methyleneglutarate mutase from the strict anaerobe Eubacterium barkeri catalyzes the equilibration of 2-methyleneglutarate with (R)-3-methylitaconate. Proteins with mutations in the highly conserved coenzyme binding-motif DXH(X)(2)G(X)(41)GG (D483N and H485Q) exhibited decreased substrate turnover by 2000-fold and >4000-fold, respectively. These findings are consistent with the notion of H485 hydrogen-bonded to D483 being the lower axial ligand of adenosylcobalamin in 2-methyleneglutarate mutase. (E)- and (Z)-2-methylpent-2-enedioate and all four stereoisomers of 1-methylcyclopropane-1,2-dicarboxylate were synthesized and tested, along with acrylate, with respect to their inhibitory potential. Acrylate and the 2-methylpent-2-enedioates were noninhibitory. Among the 1-methylcyclopropane-1,2-dicarboxylates only the (1R,2R)-isomer displayed weak inhibition (noncompetitive, K(i) = 13 mM). Short incubation (5 min) of 2-methyleneglutarate mutase with 2-methyleneglutarate under anaerobic conditions generated an electron paramagnetic resonance (EPR) signal (g(xy) approximately 2.1; g(z) approximately 2.0), which by analogy with the findings on glutamate mutase from Clostridium cochlearium [Biochemistry, 1998, 37, 4105-4113] was assigned to cob(II)alamin coupled to a carbon-centered radical. At longer incubation times (>1 h), inactivation of the mutase occurred concomitant with the formation of oxygen-insensitive cob(II)alamin (g(xy) approximately 2.25; g(z) approximately 2.0). In order to identify the carbon-centered radical, various (13)C- and one (2)H-labeled substrate/product molecules were synthesized. Broadening (0.5 mT) of the EPR signal around g = 2.1 was observed only when C2 and/or C4 of 2-methyleneglutarate was labeled. No effect on the EPR signals was seen when [5'-(13)C]adenosylcobalamin was used as coenzyme. The inhibition and EPR data are discussed in the context of the addition-elimination and fragmentation-recombination mechanisms proposed for 2-methyleneglutarate mutase.
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Affiliation(s)
- Antonio J Pierik
- Laboratorium für Mikrobiologie, Fachbereich Biologie, Philipps-Universität, Marburg, Germany
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14
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Affiliation(s)
- Kenneth L Brown
- Department of Chemistry and Biochemistry, Ohio University, Athens, 45701, USA.
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15
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Acquaviva C, Benoist JF, Pereira S, Callebaut I, Koskas T, Porquet D, Elion J. Molecular basis of methylmalonyl‐CoA mutase apoenzyme defect in 40 European patients affected by
mut
° and
mut
– forms of methylmalonic acidemia: Identification of 29 novel mutations in the MUT gene. Hum Mutat 2005; 25:167-76. [PMID: 15643616 DOI: 10.1002/humu.20128] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Methylmalonyl-CoA mutase (MCM) apoenzyme deficiency is a rare metabolic disease that may result in distinct biochemical phenotypes of methylmalonic acidemia (MMA), namely mut(o) and mut-. We analyzed a cohort of 40 MCM-deficient patients with MMA affected by either the mut(o) or the mut- form of the disease. By direct sequencing of cDNA and gDNA of the MUT gene, we detected 42 mutations, 29 of which were novel mutations. These included five frameshift mutations (insertion, deletion, or duplication of a single nucleotide), five sequence modifications in consensus splice sites, six nonsense and 12 missense mutations, and a large genomic deletion including exon 12. We explored how the 12 novel missense mutations might cause the observed phenotype by mapping them onto a three-dimensional model of the human MCM generated by homology with the P. shermanii enzyme. In this work we update the spectrum of MCM mutations (n=84), and then discuss their prevalence and distribution throughout the coding sequence in relation to the enzyme structure.
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Affiliation(s)
- Cécile Acquaviva
- Fédération de Génétique, Assistance Publique-Hôpitaux de Paris, Hôpital Robert Debré, Paris, France
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16
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Chen HP, Lung FD, Yeh CC, Chen HL, Wu SH. The role of the conserved histidine-aspartate pair in the ‘base-off’ binding of cobalamins. Bioorg Med Chem 2004; 12:577-82. [PMID: 14738967 DOI: 10.1016/j.bmc.2003.10.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The conserved cobalamin-binding domain of glutamate mutase exists as a separate dissociable subunit, MutS. The results obtained from BIAcore analysis indicate that MutS alone, in the absence of E component of glutamate mutase (MutE, catalytic subunit), is capable of binding hydroxocobinamide (OHCbi) with a Kd of 15.4+/-1.6 microM, but fails to bind adenosylcobalamin (AdoCbl). The UV-visible spectrum indicates that histidine ligation to the cobalt atom only occurs when both MutE and MutS are present in the solution. MutS mutants, MutS-D14N and MutS-H16G, are also capable of binding OHCbi, but their binding kinetics altered. Our experimental results show that the electrostatic interaction between histidine-aspartate pair is important in the binding of OHCbi or AdoCbl, no matter whether histidine coordinates to the cobalt atom or not. The catalytic subunit is also involved in histidine ligation to the cobalt atom. Meanwhile, mutation of either His16 or Asp14 significantly impairs the enzyme to cleave the cobalt-carbon bond of AdoCbl.
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Affiliation(s)
- Hao-Ping Chen
- Institute of Biotechnology and Department of Chemical Engineering, National Taipei University of Technology, 1, Sec 3, Chung-Hsiao East Road, Taipei 106, Taiwan.
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17
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Toraya T. Radical catalysis in coenzyme B12-dependent isomerization (eliminating) reactions. Chem Rev 2003; 103:2095-127. [PMID: 12797825 DOI: 10.1021/cr020428b] [Citation(s) in RCA: 312] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tetsuo Toraya
- Department of Bioscience and Biotechnology, Faculty of Engineering, Okayama University, Tsushima-naka, Okayama 700-8530, Japan.
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Banerjee R. Radical carbon skeleton rearrangements: catalysis by coenzyme B12-dependent mutases. Chem Rev 2003; 103:2083-94. [PMID: 12797824 DOI: 10.1021/cr0204395] [Citation(s) in RCA: 252] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ruma Banerjee
- Biochemistry Department, University of Nebraska, Lincoln, Nebraska 68588-0664, USA.
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