1
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Dereven'kov IA, Osokin VS, Khodov IA, Sobornova VV, Ershov NA, Makarov SV. meso-Bromination of cyano- and aquacobalamins facilitates their processing into Co(II)-species by glutathione. J Biol Inorg Chem 2023; 28:571-581. [PMID: 37479902 DOI: 10.1007/s00775-023-02009-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Accepted: 07/05/2023] [Indexed: 07/23/2023]
Abstract
Cyanocobalamin (CNCbl), a medicinal form of vitamin B12, is resistant to glutathione (GSH), and undergoes intracellular processing via reductive decyanation producing the Co(II)-form of Cbl (Cbl(II)) mediated by the CblC-protein. Alteration of the CblC-protein structure might inhibit CNCbl processing. Here, we showed that introducing a bromine atom to the C10-position of the CNCbl corrin ring facilitates its reaction with GSH leading to the formation of Cbl(II) and cyanide dissociation. In a neutral medium, the reaction between C10-Br-CNCbl and GSH proceeds via the complexation of the reactants further leading to dimethylbenzimidazole (DMBI) substitution and electron transfer from GSH to the Co(III)-ion. The reaction is accelerated upon the GSH thiol group deprotonation. The key factors explaining the higher reactivity of C10-Br-CNCbl compared with unmodified CNCbl towards GSH are increasing the electrode potential of CNCbl two-electron reduction upon meso-bromination and the substantial labilization of DMBI, which was shown by comparing their reactions with cyanide and the pKa values of DMBI protonation (pKa base-off). Aquacobalamin (H2OCbl) brominated at the C10-position of the corrin reacts with GSH to give Cbl(II) via GSH complexation and subsequent reaction of this complex with a second GSH molecule, whereas unmodified H2OCbl generates glutathionyl-Cbl, which is resistant to further reduction by GSH.
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Affiliation(s)
- Ilia A Dereven'kov
- Department of Food Chemistry, Ivanovo State University of Chemistry and Technology, Sheremetevskiy Str. 7, 153000, Ivanovo, Russia.
| | - Vladimir S Osokin
- Department of Food Chemistry, Ivanovo State University of Chemistry and Technology, Sheremetevskiy Str. 7, 153000, Ivanovo, Russia
| | - Ilya A Khodov
- G.A. Krestov Institute of Solution Chemistry, Russian Academy of Sciences, 153045, Ivanovo, Russia
| | - Valentina V Sobornova
- G.A. Krestov Institute of Solution Chemistry, Russian Academy of Sciences, 153045, Ivanovo, Russia
| | - Nikita A Ershov
- Department of Food Chemistry, Ivanovo State University of Chemistry and Technology, Sheremetevskiy Str. 7, 153000, Ivanovo, Russia
| | - Sergei V Makarov
- Department of Food Chemistry, Ivanovo State University of Chemistry and Technology, Sheremetevskiy Str. 7, 153000, Ivanovo, Russia
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2
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Marques HM. The inorganic chemistry of the cobalt corrinoids - an update. J Inorg Biochem 2023; 242:112154. [PMID: 36871417 DOI: 10.1016/j.jinorgbio.2023.112154] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 01/23/2023] [Accepted: 01/26/2023] [Indexed: 02/05/2023]
Abstract
The inorganic chemistry of the cobalt corrinoids, derivatives of vitamin B12, is reviewed, with particular emphasis on equilibrium constants for, and kinetics of, their axial ligand substitution reactions. The role the corrin ligand plays in controlling and modifying the properties of the metal ion is emphasised. Other aspects of the chemistry of these compounds, including their structure, corrinoid complexes with metals other than cobalt, the redox chemistry of the cobalt corrinoids and their chemical redox reactions, and their photochemistry are discussed. Their role as catalysts in non-biological reactions and aspects of their organometallic chemistry are briefly mentioned. Particular mention is made of the role that computational methods - and especially DFT calculations - have played in developing our understanding of the inorganic chemistry of these compounds. A brief overview of the biological chemistry of the B12-dependent enzymes is also given for the reader's convenience.
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Affiliation(s)
- Helder M Marques
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg 2050, South Africa.
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3
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The emerging role of proteolysis targeting chimeras (PROTACs) in the treatment of Alzheimer’s disease. Med Chem Res 2023. [DOI: 10.1007/s00044-023-03026-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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4
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Shimakoshi H, Hisaeda Y. Bioinspired Electrolysis for Green Molecular Transformations of Organic Halides Catalyzed by B 12 Complex. CHEM REC 2021; 21:2080-2094. [PMID: 34075694 DOI: 10.1002/tcr.202100077] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 05/10/2021] [Accepted: 05/11/2021] [Indexed: 12/27/2022]
Abstract
Naturally-occurring B12 -dependent enzymes catalyze various molecular transformations that are of particular interest from the viewpoint of biological chemistry as well as synthetic organic chemistry. Inspired by the unique property of the B12 -dependent enzymes, various catalytic reactions have been developed using its model complex. Among the B12 model complexes, heptamethyl cobyrinate, synthesized from natural vitamin B12 , is highly soluble in various organic solvents and a redox active cobalt complex with an excellent catalysis in electroorganic synthesis. The electrochemical dechlorination of pollutant organic chlorides, such as DDT, was effectively catalyzed by the B12 complex. Modification of the electrode surface by the sol-gel method to immobilize the B12 complex was also developed. The B12 modified electrodes were effective for the dehalogenation of organic halides with high turnover numbers based on the immobilized B12 complex. Electrolysis of an organic halide catalyzed by the B12 complex provided dechlorinated products under anaerobic conditions, while the electrolysis under aerobic conditions afforded oxygen incorporated products, such as an ester and amide along with dechlorination. Benzotrichloride was transformed into ethylbenzoate or N,N-diethylbenzamide in the presence of ethanol or diethylamine, respectively. This amide formation was further expanded to a unique paired electrolysis. Electrochemical reductions of an alkene and alkyne were also catalyzed by the B12 complex. A cobalt-hydrogen complex should be formed as a bioinspired intermediate. Using the B12 complex, light-assisted electrosynthesis was also developed to save the applied energy.
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Affiliation(s)
- Hisashi Shimakoshi
- Department of Chemistry and Biochemistry, Kyushu University, Nishi-ku Motooka 744, Fukuoka, 819-0395, Japan
| | - Yoshio Hisaeda
- Department of Chemistry and Biochemistry, Kyushu University, Nishi-ku Motooka 744, Fukuoka, 819-0395, Japan
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5
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Dereven'kov IA, Osokin VS, Hannibal L, Makarov SV, Khodov IA, Koifman OI. Mechanism of cyanocobalamin chlorination by hypochlorous acid. J Biol Inorg Chem 2021; 26:427-434. [PMID: 33914169 DOI: 10.1007/s00775-021-01869-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 04/22/2021] [Indexed: 11/29/2022]
Abstract
Hypochlorous acid (HOCl) is a strong oxidant produced by myeloperoxidase. Previous work suggested that HOCl modifies the corrin ring of cobalamins to yield chlorinated species via mechanisms that are incompletely understood. Herein, we report a mechanistic study on the reaction between cyanocobalamin (CNCbl, vitamin B12) and HOCl. Under weakly acidic, neutral and weakly alkaline conditions, the reaction produces the c-lactone derivative of CNCbl chlorinated at the C10-position of corrin ring (C10-Cl-CNCbl-c-lactone). Formation of C10-Cl-CNCbl-c-lactone was not observed at pH ≥ 9.9. The chlorination of CNCbl by HOCl proceeds via two pathways involving one and two HOCl molecules: the reaction is initiated by the very fast formation of a complex between CNCbl and HOCl, which either undergoes slow transformation to chlorinated species, or rapidly reacts with a second HOCl molecule to produce C10-Cl-CNCbl. Subsequent reaction of C10-Cl-CNCbl with HOCl proceeds rapidly toward lactone ring formation by H-atom abstraction at position C8. This work uncovered mechanisms and products of the reaction of a biologically active and therapeutically used cobalamin, CNCbl and the endogenous oxidant HOCl. Binding and reactivity studies of C10-Cl-CNCbl and C10-Cl-CNCbl-c-lactone with relevant proteins of the cobalamin pathway and with cultured cells are necessary to elucidate the potential physiological effects of these species.
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Affiliation(s)
- Ilia A Dereven'kov
- Ivanovo State University of Chemistry and Technology, Sheremetevskiy Str. 7, 153000, Ivanovo, Russian Federation.
| | - Vladimir S Osokin
- Ivanovo State University of Chemistry and Technology, Sheremetevskiy Str. 7, 153000, Ivanovo, Russian Federation
| | - Luciana Hannibal
- Laboratory of Clinical Biochemistry and Metabolism, Department of General Pediatrics, Adolescent Medicine and Neonatology, Faculty of Medicine, Medical Center-University of Freiburg, 79106, Freiburg, Germany
| | - Sergei V Makarov
- Ivanovo State University of Chemistry and Technology, Sheremetevskiy Str. 7, 153000, Ivanovo, Russian Federation
| | - Ilya A Khodov
- G.A. Krestov Institute of Solution Chemistry, Russian Academy of Sciences, Akademicheskaya Str. 1, 153045, Ivanovo, Russian Federation
| | - Oskar I Koifman
- Ivanovo State University of Chemistry and Technology, Sheremetevskiy Str. 7, 153000, Ivanovo, Russian Federation
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6
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Nowakowska M, Chemaly SM, Rousseau AL, Govender PP, Varadwaj PR, Varadwaj A, Yamashita K, Marques HM. Probing the nature of the Co(III) ion in corrins: The reactions of aquacyano-5-seco-cobyrinic acid heptamethyl ester with anionic ligands. Inorganica Chim Acta 2019. [DOI: 10.1016/j.ica.2018.09.073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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7
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Wierzba AJ, Wincenciuk A, Karczewski M, Vullev VI, Gryko D. meso
‐Modified Cobalamins: Synthesis, Structure, and Properties. Chemistry 2018; 24:10344-10356. [DOI: 10.1002/chem.201801807] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Aleksandra J. Wierzba
- Institute of Organic Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
| | - Aleksandra Wincenciuk
- Institute of Organic Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
- Department of Chemistry University of Warsaw Pasteura 1 02-093 Warsaw Poland
| | - Maksymilian Karczewski
- Institute of Organic Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
| | - Valentine I. Vullev
- Bioengineering, Chemistry, Biochemistry, and Materials Science and Engineering University of California, Riverside Materials Science and Engineering Building, Room 235 Riverside CA 92521 USA
| | - Dorota Gryko
- Institute of Organic Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
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8
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Prieto L, Rossier J, Derszniak K, Dybas J, Oetterli RM, Kottelat E, Chlopicki S, Zelder F, Zobi F. Modified biovectors for the tuneable activation of anti-platelet carbon monoxide release. Chem Commun (Camb) 2018; 53:6840-6843. [PMID: 28603801 DOI: 10.1039/c7cc03642f] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This communication describes the anti-platelet effects of a new class of cis-rhenium(ii)-dicarbonyl-vitamin B12 complexes (B12-ReCORMs) with tuneable CO releasing properties.
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Affiliation(s)
- Lucas Prieto
- University of Zurich, Department of Chemistry, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
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9
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Karczewski M, Ociepa M, Pluta K, ó Proinsias K, Gryko D. Vitamin B12
Catalysis: Probing the Structure/Efficacy Relationship. Chemistry 2017; 23:7024-7030. [DOI: 10.1002/chem.201606059] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Maksymilian Karczewski
- Institute of Organic Chemistry; Polish Academy of Sciences; Kasprzaka 44/52 01-224 Warsaw Poland
| | - Michał Ociepa
- Institute of Organic Chemistry; Polish Academy of Sciences; Kasprzaka 44/52 01-224 Warsaw Poland
| | - Katarzyna Pluta
- Institute of Organic Chemistry; Polish Academy of Sciences; Kasprzaka 44/52 01-224 Warsaw Poland
| | - Keith ó Proinsias
- Institute of Organic Chemistry; Polish Academy of Sciences; Kasprzaka 44/52 01-224 Warsaw Poland
| | - Dorota Gryko
- Institute of Organic Chemistry; Polish Academy of Sciences; Kasprzaka 44/52 01-224 Warsaw Poland
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10
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Probing the nature of the Co(III) ion in cobalamins: The ligand substitution reactions of aquacyanocobester, aquacyano(10-nitro)cobester and aquacyano(10-amino)cobester. Inorganica Chim Acta 2016. [DOI: 10.1016/j.ica.2016.06.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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11
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Schrapers P, Mebs S, Goetzl S, Hennig SE, Dau H, Dobbek H, Haumann M. Axial Ligation and Redox Changes at the Cobalt Ion in Cobalamin Bound to Corrinoid Iron-Sulfur Protein (CoFeSP) or in Solution Characterized by XAS and DFT. PLoS One 2016; 11:e0158681. [PMID: 27384529 PMCID: PMC4934906 DOI: 10.1371/journal.pone.0158681] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 06/20/2016] [Indexed: 11/18/2022] Open
Abstract
A cobalamin (Cbl) cofactor in corrinoid iron-sulfur protein (CoFeSP) is the primary methyl group donor and acceptor in biological carbon oxide conversion along the reductive acetyl-CoA pathway. Changes of the axial coordination of the cobalt ion within the corrin macrocycle upon redox transitions in aqua-, methyl-, and cyano-Cbl bound to CoFeSP or in solution were studied using X-ray absorption spectroscopy (XAS) at the Co K-edge in combination with density functional theory (DFT) calculations, supported by metal content and cobalt redox level quantification with further spectroscopic methods. Calculation of the highly variable pre-edge X-ray absorption features due to core-to-valence (ctv) electronic transitions, XANES shape analysis, and cobalt-ligand bond lengths determination from EXAFS has yielded models for the molecular and electronic structures of the cobalt sites. This suggested the absence of a ligand at cobalt in CoFeSP in α-position where the dimethylbenzimidazole (dmb) base of the cofactor is bound in Cbl in solution. As main species, (dmb)CoIII(OH2), (dmb)CoII(OH2), and (dmb)CoIII(CH3) sites for solution Cbl and CoIII(OH2), CoII(OH2), and CoIII(CH3) sites in CoFeSP-Cbl were identified. Our data support binding of a serine residue from the reductive-activator protein (RACo) of CoFeSP to the cobalt ion in the CoFeSP-RACo protein complex that stabilizes Co(II). The absence of an α-ligand at cobalt not only tunes the redox potential of the cobalamin cofactor into the physiological range, but is also important for CoFeSP reactivation.
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Affiliation(s)
- Peer Schrapers
- Freie Universität Berlin, Department of Physics, 14195, Berlin, Germany
| | - Stefan Mebs
- Freie Universität Berlin, Department of Physics, 14195, Berlin, Germany
| | - Sebastian Goetzl
- Humboldt-Universität zu Berlin, Department of Biology, 10115, Berlin, Germany
| | - Sandra E. Hennig
- Humboldt-Universität zu Berlin, Department of Biology, 10115, Berlin, Germany
| | - Holger Dau
- Freie Universität Berlin, Department of Physics, 14195, Berlin, Germany
| | - Holger Dobbek
- Humboldt-Universität zu Berlin, Department of Biology, 10115, Berlin, Germany
| | - Michael Haumann
- Freie Universität Berlin, Department of Physics, 14195, Berlin, Germany
- * E-mail:
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12
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Morita Y, Oohora K, Mizohata E, Sawada A, Kamachi T, Yoshizawa K, Inoue T, Hayashi T. Crystal Structures and Coordination Behavior of Aqua- and Cyano-Co(III) Tetradehydrocorrins in the Heme Pocket of Myoglobin. Inorg Chem 2016; 55:1287-95. [DOI: 10.1021/acs.inorgchem.5b02598] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yoshitsugu Morita
- Department of Applied Chemistry, Graduate
School of Engineering, Osaka University, Suita 565-0871, Japan
| | - Koji Oohora
- Department of Applied Chemistry, Graduate
School of Engineering, Osaka University, Suita 565-0871, Japan
- Frontier Research Base for Global Young
Researchers, Graduate School of Engineering, Osaka University, Suita 565-0871, Japan
| | - Eiichi Mizohata
- Department of Applied Chemistry, Graduate
School of Engineering, Osaka University, Suita 565-0871, Japan
| | - Akiyoshi Sawada
- Institute
for Materials Chemistry and Engineering and International Research
Center for Molecular Systems, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
| | - Takashi Kamachi
- Institute
for Materials Chemistry and Engineering and International Research
Center for Molecular Systems, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
| | - Kazunari Yoshizawa
- Institute
for Materials Chemistry and Engineering and International Research
Center for Molecular Systems, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
- Elements
Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, Nishikyo-ku, Kyoto 615-8520, Japan
| | - Tsuyoshi Inoue
- Department of Applied Chemistry, Graduate
School of Engineering, Osaka University, Suita 565-0871, Japan
| | - Takashi Hayashi
- Department of Applied Chemistry, Graduate
School of Engineering, Osaka University, Suita 565-0871, Japan
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13
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Santoro G, Beltrami R, Kottelat E, Blacque O, Bogdanova AY, Zobi F. N-Nitrosamine-{cis-Re[CO]2}2+ cobalamin conjugates as mixed CO/NO-releasing molecules. Dalton Trans 2016; 45:1504-13. [DOI: 10.1039/c5dt03402g] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mixed CO/NO-releasing molecules were prepared by conjugation of the 17-electron rhenium dicarbonyl cis-[Re(CO)2Br4]2− complex to N-nitrosamine modified cyanocobalamin (B12) bio-vectors.
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Affiliation(s)
- Giuseppe Santoro
- Department of Chemistry
- University of Zürich
- CH-8057 Zürich
- Switzerland
| | - Ruben Beltrami
- Department of Chemistry
- University of Fribourg
- CH-1700 Fribourg
- Switzerland
| | - Emmanuel Kottelat
- Department of Chemistry
- University of Fribourg
- CH-1700 Fribourg
- Switzerland
| | - Olivier Blacque
- Department of Chemistry
- University of Zürich
- CH-8057 Zürich
- Switzerland
| | - Anna Yu. Bogdanova
- Institute of Veterinary Physiology
- University of Zürich
- CH-8057 Zürich
- Switzerland
| | - Fabio Zobi
- Department of Chemistry
- University of Fribourg
- CH-1700 Fribourg
- Switzerland
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14
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Ghadimi N, Perry CB, Fernandes MA, Govender PP, Marques HM. Probing the nature of the Co(III) ion in cobalamins: The reactions of aquacobalamin (vitamin B12a), aqua-10-chlorocobalamin and aqua-10-bromocobalamin with anionic and neutral ligands. Inorganica Chim Acta 2015. [DOI: 10.1016/j.ica.2015.07.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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15
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Zelder F. Recent trends in the development of vitamin B12 derivatives for medicinal applications. Chem Commun (Camb) 2015; 51:14004-17. [PMID: 26287029 DOI: 10.1039/c5cc04843e] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This Feature Article highlights recent developments in the field of vitamin B12 derivatives for medicinal applications. The following topics are emphasized: (1) the development of aquacorrinoids for cyanide detection and detoxification, (2) the use of vitamin B12 conjugates and (3) antivitamins B12 for therapy and diagnosis, and (4) the design of corrinoids as activators of soluble guanylyl cyclase (sGC).
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Affiliation(s)
- Felix Zelder
- Department of Chemistry, University of Zürich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland.
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16
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Zipp CF, Michael JP, Fernandes MA, Nowakowska M, Dirr HW, Marques HM. The kinetics of the substitution of coordinated H2O on Co(III) by cyanide in aquacobalamin (vitamin B12a) and in a corrole analogue. INORG CHEM COMMUN 2015. [DOI: 10.1016/j.inoche.2015.04.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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17
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Maitra D, Ali I, Abdulridha RM, Shaeib F, Khan SN, Saed GM, Pennathur S, Abu-Soud HM. Kinetic studies on the reaction between dicyanocobinamide and hypochlorous acid. PLoS One 2014; 9:e110595. [PMID: 25375773 PMCID: PMC4222763 DOI: 10.1371/journal.pone.0110595] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 09/17/2014] [Indexed: 12/15/2022] Open
Abstract
Hypochlorous acid (HOCl) is a potent oxidant generated by myeloperoxidase (MPO), which is an abundant enzyme used for defense against microbes. We examined the potential role of HOCl in corrin ring destruction and subsequent formation of cyanogen chloride (CNCl) from dicyanocobinamide ((CN)2-Cbi). Stopped-flow analysis revealed that the reaction consists of at least three observable steps, including at least two sequential transient intermediates prior to corrin ring destruction. The first two steps were attributed to sequential replacement of the two cyanide ligands with hypochlorite, while the third step was the destruction of the corrin ring. The formation of (OCl)(CN)-Cbi and its conversion to (OCl)2-Cbi was fitted to a first order rate equation with second order rate constants of 0.002 and 0.0002 µM−1s−1, respectively. The significantly lower rate of the second step compared to the first suggests that the replacement of the first cyanide molecule by hypochlorite causes an alteration in the ligand trans effects changing the affinity and/or accessibility of Co toward hypochlorite. Plots of the apparent rate constants as a function of HOCl concentration for all the three steps were linear with Y-intercepts close to zero, indicating that HOCl binds in an irreversible one-step mechanism. Collectively, these results illustrate functional differences in the corrin ring environments toward binding of diatomic ligands.
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Affiliation(s)
- Dhiman Maitra
- Department of Obstetrics and Gynecology, The C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, United States of America
| | - Iyad Ali
- Department of Obstetrics and Gynecology, The C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, United States of America
- Department of Biochemistry and Genetics, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
| | - Rasha M. Abdulridha
- Department of Obstetrics and Gynecology, The C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, United States of America
| | - Faten Shaeib
- Department of Obstetrics and Gynecology, The C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, United States of America
| | - Sana N. Khan
- Department of Obstetrics and Gynecology, The C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, United States of America
| | - Ghassan M. Saed
- Department of Obstetrics and Gynecology, The C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, United States of America
| | - Subramaniam Pennathur
- Division of Nephrology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, United States of America
| | - Husam M. Abu-Soud
- Department of Obstetrics and Gynecology, The C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, United States of America
- Department of Biochemistry and Molecular Biology, The C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, United States of America
- * E-mail:
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18
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Zipp CF, Michael JP, Fernandes MA, Mathura S, Perry CB, Navizet I, Govender PP, Marques HM. The Synthesis of a Corrole Analogue of Aquacobalamin (Vitamin B12a) and Its Ligand Substitution Reactions. Inorg Chem 2014; 53:4418-29. [DOI: 10.1021/ic5000793] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Caitlin F. Zipp
- Molecular
Sciences Institute, School of Chemistry, University of the Witwatersrand, P.O. Wits, Johannesburg, 2050 South Africa
| | - Joseph P. Michael
- Molecular
Sciences Institute, School of Chemistry, University of the Witwatersrand, P.O. Wits, Johannesburg, 2050 South Africa
| | - Manuel A. Fernandes
- Molecular
Sciences Institute, School of Chemistry, University of the Witwatersrand, P.O. Wits, Johannesburg, 2050 South Africa
| | - Sadhna Mathura
- Molecular
Sciences Institute, School of Chemistry, University of the Witwatersrand, P.O. Wits, Johannesburg, 2050 South Africa
| | - Christopher B. Perry
- Molecular
Sciences Institute, School of Chemistry, University of the Witwatersrand, P.O. Wits, Johannesburg, 2050 South Africa
| | - Isabelle Navizet
- Molecular
Sciences Institute, School of Chemistry, University of the Witwatersrand, P.O. Wits, Johannesburg, 2050 South Africa
| | - Penny P. Govender
- Department
of Applied Chemistry, University of Johannesburg, P.O. Box 17011, Doornfontein, Johannesburg, 2028 South Africa
| | - Helder M. Marques
- Molecular
Sciences Institute, School of Chemistry, University of the Witwatersrand, P.O. Wits, Johannesburg, 2050 South Africa
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19
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Mathura S, Sannasy D, de Sousa AS, Perry CB, Navizet I, Marques HM. The preparation of N-acetyl-Co(III)-microperoxidase-8 (NAcCoMP8) and its ligand substitution reactions: A comparison with aquacobalamin (vitamin B12a). J Inorg Biochem 2013; 123:66-79. [DOI: 10.1016/j.jinorgbio.2013.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 03/01/2013] [Accepted: 03/04/2013] [Indexed: 12/01/2022]
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20
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Chemaly SM, Kendall L, Nowakowska M, Pon D, Perry CB, Marques HM. Probing the nature of the Co(III) ion in corrins: comparison of reactions of aquacyanocobyrinic acid heptamethyl ester and aquacyano-stable yellow cobyrinic acid hexamethyl ester with neutral N-donor ligands. Inorg Chem 2013; 52:1077-83. [PMID: 23268626 DOI: 10.1021/ic302386u] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Equilibrium constants (log K) for substitution of coordinated H(2)O in aquacyanocobyrinic acid heptamethyl ester (aquacyanocobester, ACCbs) and aquacyano-stable yellow cobyrinic acid hexamethyl ester (aquacyano-stable yellow cobester, ACSYCbs), in which oxidation of the C5 carbon of the corrin interrupts the normal delocalized system of corrins, by neutral N-donor ligands (ammonia, ethanolamine, 2-methoxyethylamine, N-methylimidazole, and 4-methylpyridine) have been determined spectrophotometrically as a function of temperature. Log K values increase with the basicity of the ligand, but a strong compensation effect between ΔH and ΔS values causes a leveling effect. The aliphatic amines with a harder donor atom produce ΔH values that are more negative in their reactions with ACSYCbs than with ACCbs, while the softer, aromatic N donors produce more negative ΔH values with ACCbs than with ACSYCbs. Molecular modeling (DFT, M06L/SVP, and a quantum theory of atoms in molecules analysis of the electron density) shows that complexes of the aliphatic amines with SYCbs produce shorter and stronger Co-N bonds with less ionic character than the Co-N bonds of these ligands with the cobester. Conversely, the Co-N bond to the aromatic N donors is shorter, stronger, and somewhat less ionic in the complexes of the cobester than in those of the SYCbs. Therefore, the distinction between the harder Co(III) in ACSYCbs and softer Co(III) in ACCbs, reported previously for anionic ligands, is maintained for neutral N-donor ligands.
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Affiliation(s)
- Susan M Chemaly
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, PO Wits, Johannesburg, 2050 South Africa.
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21
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Govender PP, Navizet I, Perry CB, Marques HM. The cis influence of the corrin in vitamin B12 models. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2012.08.061] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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22
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Navizet I, Perry CB, Govender PP, Marques HM. cis Influence in Models of Cobalt Corrins by DFT and TD-DFT Studies. J Phys Chem B 2012; 116:8836-45. [DOI: 10.1021/jp304007a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Isabelle Navizet
- Molecular Sciences
Institute, School of Chemistry, University of Witwatersrand, P.O. Wits, Johannesburg, 2050 South
Africa
| | - Christopher B. Perry
- Molecular Sciences
Institute, School of Chemistry, University of Witwatersrand, P.O. Wits, Johannesburg, 2050 South
Africa
| | - Penny P. Govender
- Molecular Sciences
Institute, School of Chemistry, University of Witwatersrand, P.O. Wits, Johannesburg, 2050 South
Africa
- Department
of Applied
Chemistry, University of Johannesburg, P.O. Box 17011, Doornfontein, Johannesburg, 2028 South Africa
| | - Helder M. Marques
- Molecular Sciences
Institute, School of Chemistry, University of Witwatersrand, P.O. Wits, Johannesburg, 2050 South
Africa
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23
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Prakash J, Kodanko JJ. Synthesis, Characterization, and Glutathionylation of Cobalamin Model Complexes [Co(N4PyCO2Me)Cl]Cl2 and [Co(Bn-CDPy3)Cl]Cl2. Inorg Chem 2012; 51:2689-98. [DOI: 10.1021/ic2026736] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Jai Prakash
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit,
Michigan 48202, United States
| | - Jeremy J. Kodanko
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit,
Michigan 48202, United States
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Chemaly SM, Brown KL, Fernandes MA, Munro OQ, Grimmer C, Marques HM. Probing the Nature of the CoIII Ion in Corrins: The Structural and Electronic Properties of Dicyano- and Aquacyanocobyrinic Acid Heptamethyl Ester and a Stable Yellow Dicyano- and Aquacyanocobyrinic Acid Heptamethyl Ester. Inorg Chem 2011; 50:8700-18. [DOI: 10.1021/ic200285k] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Susan M. Chemaly
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, PO Wits, Johannesburg, 2050 South Africa
| | - Kenneth L. Brown
- Department of Chemistry, Ohio University, Athens, Ohio 45701, United States
| | - Manuel A. Fernandes
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, PO Wits, Johannesburg, 2050 South Africa
| | - Orde Q. Munro
- School of Chemistry, University of KwaZulu-Natal, Scottsville, Pietermaritzburg, 3209 South Africa
| | - Craig Grimmer
- School of Chemistry, University of KwaZulu-Natal, Scottsville, Pietermaritzburg, 3209 South Africa
| | - Helder M. Marques
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, PO Wits, Johannesburg, 2050 South Africa
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Marino N, Rabideau AE, Doyle RP. Trifluoracetic acid-assisted crystallization of vitamin B12 results in protonation of the phosphate group of the nucleotide loop: insight into the influence of crystal packing forces on vitamin B12 structures. Inorg Chem 2010; 50:220-30. [PMID: 21128680 DOI: 10.1021/ic101810v] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In the course of experiments concerning our ongoing project on the synthesis of vitamin B(12) (cyanocobalamin, CNCbl) bioconjugates for drug-delivery purposes, we observed the formation of well-shaped red parallelepipeds from a concentrated aqueous solution of the HPLC-purified vitamin. The X-ray structural investigation (MoK(α)) at 98 K on these crystals revealed a CNCbl-TFA salt of formula [CNCbl(H)](TFAc)·14H(2)O (1, where TFA = trifluoracetic acid; TFAc(-) = trifluoracetate anion), in which a proton transfer from the trifluoracetic acid to the phosphate-O4P oxygen atoms is observed. 1 crystallizes in the standard orthorhombic P2(1)2(1)2(1) space group, a = 16.069(2) Å, b = 20.818(2) Å, c = 24.081(2) Å, Z = 4. The final full-matrix least-squares refinements on F(2) converged with R(1) = 4.1% for the 18957 significant reflections, a very low crystallographic residual for cobalamins, which facilitated the analysis of the extensive network of hydrogen bonds within the lattice. To the best of our knowledge, this is the first cobalamin structure to show protonation of the phosphate group of the cobalamin nucleotide loop. In this work, the crystal structure of 1 is analyzed and compared to other CNCbls reported in the literature, namely, CNCbl·3PrOH·12H(2)O (2, PrOH = propyl alcohol), CNCbl·acetone·20H(2)O (3), CNCbl·2LiCl·10.2H(2)O (4), and CNCbl·2KCl·10.6H(2)O (5). The analysis confirmed that protonation of the phosphate leaves the major CNCbl structural parameters unaffected, so that 1 can be considered an "unmodified" Cbl solvate. However, comparison between 1-5 led to interesting findings. In fact, although the cobalt(III) coordination sphere in 1-5 is similar, significant differences could be noted in the upward fold angle of the corrin macrocycle, a parameter commonly related to the steric hindrance of the axial lower "α" nucleotide-base and the electronic trans influence of the upper "β" substituent. This suggests that crystal-packing forces may influence the corrin deformation as well. Herein we explore, on the basis of the newly acquired structure and reported crystallographic data, whether the incongruities among 1-5 have to be attributed to random crystal packing effects or if it is possible to associate them with specific crystal packing (clusters).
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Affiliation(s)
- Nadia Marino
- Department of Chemistry, Syracuse University, Syracuse, New York 13244-4100, USA
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26
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Hannibal L, Smith CA, Smith JA, Axhemi A, Miller A, Wang S, Brasch NE, Jacobsen DW. High resolution crystal structure of the methylcobalamin analogues ethylcobalamin and butylcobalamin by X-ray synchrotron diffraction. Inorg Chem 2010; 48:6615-22. [PMID: 19545130 DOI: 10.1021/ic900590p] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The X-ray crystal structures of the methylcobalamin (MeCbl) analogues ethylcobalamin (EtCbl) and butylcobalamin (BuCbl) are reported. The X-ray crystal structures of EtCbl and BuCbl were obtained with some of the lowest crystallographic residuals ever achieved for cobalamins (R = 0.0468 and 0.0438, respectively). The Co-C bond distances for EtCbl and BuCbl are 2.023(2) and 2.028(4) A, whereas the Co-alpha-5,6-dimethylbenzimidazole (Co-N3B) bond distances were 2.232(1) and 2.244(1) A, respectively. Although EtCbl and BuCbl displayed a longer Co-N3B bond than that observed in the naturally occurring methylcobalamin, the orientation of the alpha-5,6-dimethylbenzimidazole moiety with respect to the corrin ring did not vary substantially among the structures. The lengthening of both Co-C and Co-N3B bonds in EtCbl and BuCbl can be attributed to the "inverse" trans influence exerted by the sigma-donating alkyl groups, typically observed in alkylcobalamins. Analysis of the molecular surface maps showed that the alkyl ligands in EtCbl and BuCbl are directed toward the hydrophobic side of the corrin ring. The corrin fold angles in EtCbl and BuCbl were determined to be 14.7 degrees and 13.1 degrees, respectively. A rough correlation exists between the corrin fold angle and the length of the Co-N3B bond, and both alkylcobalamins follow the same trend.
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Affiliation(s)
- Luciana Hannibal
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA
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27
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Spingler B, Mundwiler S, Ruiz-Sánchez P, van Staveren DR, Alberto R. Structures of the b- and d-Acid Derivatives of Vitamin B12 and Their Complexes with [M(CO)3]+ (M =99mTc, Re). Eur J Inorg Chem 2007. [DOI: 10.1002/ejic.200601195] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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28
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Baikalova LV, Sokol VI, Zyryanova IA, Fedyanin IV, Khrustalev VN, Zel’bst EA, Tarasova OA, Sergienko VS, Trofimov BA. Crystal and molecular structures of the complexes of cobalt dichloride with 1-isopropenylimidazole and 1-vinylimidazole. RUSS J GEN CHEM+ 2006. [DOI: 10.1134/s1070363206050227] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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29
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Ouyang L, Rulis P, Ching WY, Slouf M, Nardin G, Randaccio L. Electronic structure and bonding in hydroxocobalamin. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2005; 61:1647-1652. [PMID: 15820898 DOI: 10.1016/j.saa.2004.11.066] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2004] [Accepted: 11/25/2004] [Indexed: 05/24/2023]
Abstract
The electronic structure of hydroxocobalamin (OHCbl) has been calculated by a density functional method, using the orthogonalized linear combination of the atomic orbitals method (OLCAO). The X-ray crystal structure has been determined from synchrotron X-ray diffraction data and the geometry determined was used in the calculations. Comparison with the recently reported electronic structures of cyanocobalamin (CNCbl), methylcobalamin (MeCbl) and adenosylcobalamin (AdoCbl) shows that Mulliken charges (Q*) and bond orders (BO) vary only on the axial fragment.
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Affiliation(s)
- Lizhi Ouyang
- Department of Physics, University of Missouri-Kansas City, Kansas City, MO 64110, USA
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30
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Perry CB, Brown KL, Zou X, Marques HM. The solution structure of some cobalamins determined by NMR-restrained molecular modelling. J Mol Struct 2005. [DOI: 10.1016/j.molstruc.2004.10.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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31
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Knapton L, Marques HM. Probing the nature of the Co(III) ion in cobalamins: a comparison of the reaction of aquacobalamin (vitamin B12a) and aqua-10-chlorocobalamin with some anionic and N-donor ligands. Dalton Trans 2005:889-95. [PMID: 15726141 DOI: 10.1039/b416083e] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
To probe the cis effect of the corrin macrocycle in vitamin B12 derivatives, equilibrium constants for the substitution of coordinated H2O in aquacobalamin (vitamin B12a, H2OCbl+) and in aqua-10-chlorocobalamin, H2O-10-ClCbl+, (in which Cl has replaced the C10 H) by an exogenous ligand, L (L = an anion, NO2-, SCN-, N3-, OCN-, S2O3(2-), NCSe- or a neutral N-donor, CH3NH2, pyridine, imidazole) have been determined. The cis influence reported in the electronic spectra of the cobalamins is observed in the spectra of L-10-ClCbls as well. Anionic ligands bind more strongly to H2O-10-ClCbl+ than to H2OCbl+ with log K values between 0.10 and 0.63 (average 0.26) larger; the converse is true for the neutral N-donor ligands, where log K is between 0.17 and 0.3 (average 0.25) smaller. Semi-empirical molecular orbital (SEMO) calculations using the ZINDO/1 model on the hydroxo complexes show that charge density is delocalised from the axial donor atom to the metal and Cl. This explains why coordinated OH- is a poorer base in HO-10-ClCbl than in HOCbl and the pK(a) of H2O-10-ClCbl+ is lower than that of H2OCbl+. It further explains why, because of the ability of the metal in concert with the C10 Cl to accept charge density from the ligand, an anionic ligand will bind more strongly to Co(III) in H2O-10-ClCbl+ than in H2OCbl+. The kinetics of the replacement of coordinated H2O by two probe ligand, pyridine and azide, were determined. The rate constants for substitution of H2O in H2O-10-ClCbl+ by pyridine show saturation, whilst those for substitution by N3- do not; this is inconsistent with a purely dissociative mechanism and the reactions proceed through an interchange mechanism. The values of the activation parameters are more positive for the reaction between these ligands and H2OCbl+, than for their reaction with H2O-10-ClCbl+. This is interpreted to mean that the transition state in the reaction of H2O-10-ClCbl+ occurs earlier along the reaction coordinate. In the temperature range studied, H2O-10-ClCbl+ reacts more slowly with py and N3- than does H2OCbl+. SEMO calculations indicate that as the Co-O bond to the departing H(2)O molecule is stretched, the charge density on Co in H2OCbl+ is always lower than on Co in H2O-10-ClCbl+. This suggests that the former is a better electrophile towards the incoming ligand, and offers an explanation for the kinetics observations.
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Affiliation(s)
- Leanne Knapton
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, PO Wits, Johannesburg, 2050, South Africa
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32
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Brown KL, Zou X, Banka RR, Perry CB, Marques HM. Solution Structure and Thermolysis of Coβ-5‘-Deoxyadenosylimidazolylcobamide, a Coenzyme B12 Analogue with an Imidazole Axial Nucleoside. Inorg Chem 2004; 43:8130-42. [PMID: 15578853 DOI: 10.1021/ic040079z] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The solution structure of Cobeta-5'-deoxyadenosylimidazolylcobamide, Ado(Im)Cbl, the coenzyme B(12) analogue in which the axial 5,6-dimethylbenzimidazole (Bzm) ligand is replaced by imidazole, has been determined by NMR-restrained molecular modeling. A two-state model, in which a conformation with the adenosyl moiety over the southern quadrant of the corrin and a conformation with the adenosyl ligand over the eastern quadrant of the corrin are both populated at room temperature, was required by the nOe data. A rotation profile and molecular dynamics simulations suggest that the eastern conformation is the more stable, in contrast to AdoCbl itself in which the southern conformation is preferred. Consensus structures of the two conformers show that the axial Co-N bond is slightly shorter and the corrin ring is less folded in Ado(Im)Cbl than in AdoCbl. A study of the thermolysis of Ado(Im)Cbl in aqueous solution (50-125 degrees C) revealed competing homolytic and heterolytic pathways as for AdoCbl but with heterolysis being 9-fold faster and homolysis being 3-fold slower at 100 degrees C than for AdoCbl. Determination of the pK(a)'s for the Ado(Im)Cbl base-on/base-off reaction and for the detached imidazole ribonucleoside as a function of temperature permitted correction of the homolysis and heterolysis rate constants for the temperature-dependent presence of the base-off species of Ado(Im)Cbl. Activation analysis of the resulting rate constants for the base-on species show that the entropy of activation for Ado(Im)Cbl homolysis (13.7 +/- 0.9 cal mol(-1) K(-1)) is identical with that of AdoCbl (13.5 +/- 0.7 cal mol(-1) K(-1)) but that the enthalpy of activation (34.8 kcal mol(-1)) is 1.0 +/- 0.4 kcal mol(-1) larger. The opposite effect is seen for heterolysis, where the enthalpies of activation are identical but the entropy of activation is 5 +/- 1 cal mol(-1) K(-1) less negative for Ado(Im)Cbl. Extrapolation to 37 degrees C provides a rate constant for Ado(Im)Cbl homolysis of 2.1 x 10(-9) s(-1), 4.3-fold smaller than for AdoCbl. Combined with earlier results for the enzyme-induced homolysis of Ado(Im)Cbl by the ribonucleoside triphosphate reductase from Lactobacillus leichmannii, the catalytic efficiency of the enzyme for homolysis of Ado(Im)Cbl at 37 degrees C can be calculated to be 4.0 x 10(8), 3.8-fold, or 0.8 kcal mol(-1), smaller than for AdoCbl. Thus, the bulky Bzm ligand makes at best a <1 kcal mol(-1) contribution to the enzymatic activation of coenzyme B(12).
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Affiliation(s)
- Kenneth L Brown
- Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, USA.
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33
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Perry C, Fernandes M, Zou X, Valente E, Marques H. Probing the Nature of the CoIII Ion in Cobalamins − Spectroscopic and Structural Investigations of the Reactions of Aquacobalamin (Vitamin B12a) with Ambident Nucleophiles. Eur J Inorg Chem 2003. [DOI: 10.1002/ejic.200200600] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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34
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Marques HM, Brown KL. Molecular mechanics and molecular dynamics simulations of porphyrins, metalloporphyrins, heme proteins and cobalt corrinoids. Coord Chem Rev 2002. [DOI: 10.1016/s0010-8545(01)00411-8] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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35
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Marques HM, Knapton L, Zou X, Brown KL. Probing the nature of the Co(iii) ion in cobalamins: deactivation of the metal towards ligand substitution in 10-nitrosoaquacobalamin, and the kinetics of the ligand substitution reactions of iodocobalamin. ACTA ACUST UNITED AC 2002. [DOI: 10.1039/b202158g] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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36
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Dölker N, Maseras F, Lledós A. A Density Functional Study on the Effect of the Trans Axial Ligand of Cobalamin on the Homolytic Cleavage of the Co−C Bond. J Phys Chem B 2001. [DOI: 10.1021/jp010144f] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Nicole Dölker
- Unitat de Química Física, Edifici C.n, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia, Spain
| | - Feliu Maseras
- Unitat de Química Física, Edifici C.n, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia, Spain
| | - Agustí Lledós
- Unitat de Química Física, Edifici C.n, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia, Spain
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37
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Meskers SCJ, Dekkers HPJM. Enantioselective Quenching of Luminescence: Molecular Recognition of Chiral Lanthanide Complexes by Biomolecules in Solution. J Phys Chem A 2001. [DOI: 10.1021/jp004428w] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Stefan C. J. Meskers
- Eindhoven University of Technology, Laboratory of Macromolecular and Organic Chemistry, P.O. Box 513, NL-5600 MB Eindhoven, The Netherlands
| | - Harry P. J. M. Dekkers
- Eindhoven University of Technology, Laboratory of Macromolecular and Organic Chemistry, P.O. Box 513, NL-5600 MB Eindhoven, The Netherlands
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Hamza MS, Dücker-Benfer C, van Eldik R. Ligand substitution behavior of a simple model for coenzyme B12. Inorg Chem 2000; 39:3777-83. [PMID: 11196769 DOI: 10.1021/ic000023e] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ligand substitution reactions of trans-[CoIII(en)2(Me)H2O]2+, a simple model for coenzyme B12, were studied for cyanide and imidazole as entering nucleophiles. It was found that these nucleophiles displace the coordinated water molecule trans to the methyl group and form the six-coordinate complex trans-[Co(en)2(Me)L]. The complex-formation constants for cyanide and imidazole were found to be (8.3 +/- 0.7) x 10(4) and 24.5 +/- 2.2 M-1 at 10 and 12 degrees C, respectively. The second-order rate constants for the substitution of water were found to be (3.3 +/- 0.1) x 10(3) and 198 +/- 13 M-1 s-1 at 25 degrees C for cyanide and imidazole, respectively. From temperature and pressure dependence studies, the activation parameters delta H++, delta S++, and delta V++ for the reaction of trans-[CoIII(en)2(Me)H2O]2+ with cyanide were found to be 50 +/- 4 kJ mol-1, 0 +/- 16 J K-1 mol-1, and +7.0 +/- 0.6 cm3 mol-1, respectively, compared to 53 +/- 2 kJ mol-1, -22 +/- 7 J K-1 mol-1, and +4.7 +/- 0.1 cm3 mol-1 for the reaction with imidazole. On the basis of reported activation volumes, these reactions follow a dissociative mechanism in which the entering nucleophile could be weakly bound in the transition state.
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Affiliation(s)
- M S Hamza
- Institute for Inorganic Chemistry, University of Erlangen-Nürnberg, Egerlandstrasse 1, 91058 Erlangen, Germany
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39
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Randaccio L, Furlan M, Geremia S, Slouf M, Srnova I, Toffoli D. Similarities and differences between cobalamins and cobaloximes. Accurate structural determination of methylcobalamin and of LiCl- and KCl-containing cyanocobalamins by synchrotron radiation. Inorg Chem 2000; 39:3403-13. [PMID: 11196881 DOI: 10.1021/ic0001199] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The accurate crystal structure determinations of MeCbl (1), CNCbl.2LiCl (2), and CNCbl.KCl (3), based on synchrotron diffraction data collected at 100 K and using high-quality single crystals, are reported. Refinements gave R1 indices of 0.0834 (1), 0.0434 (2), and 0.0773 (3). The influence of the water of crystallization and ion content on the crystal packing of these and other cobalamins (XCbl) is discussed, and a relationship between the crystal packing and the corrin side chain conformations is presented. An analysis of the bond lengths within the corrin moiety, based on 13 accurate structures with several X groups, shows that the trend of the C-C and C-N distances can be interpreted in terms of electronic and steric factors. The variation in structural, NMR and IR spectroscopic, and electrochemical properties are compared with those of cobaloximes, the B12 model, when X is varied. This comparison indicates that the pi-back-donation from metal to the CN axial ligand and the transmission of the trans influence of the X ligand are more effective in cobalamins than in cobaloximes. These findings are consistent with a significantly greater availability of electron charge on Co in cobalamins, and, hence, a semiquantitative evaluation of the electronic difference between the cobalt centers in the two systems is allowed.
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Affiliation(s)
- L Randaccio
- Dipartimento di Scienze Chimiche, University of Trieste, 34127 Trieste, Italy
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40
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Marques H, Zou X, Brown K. The solution structure of adenosylcobalamin and adenosylcobinamide determined by nOe-restrained molecular dynamics simulations. J Mol Struct 2000. [DOI: 10.1016/s0022-2860(99)00309-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Randaccio L. Vitamin B12Coenzyme Models: Perspectives on Recent Developments in the Chemistry of the Cobaloximes and Related Models. COMMENT INORG CHEM 1999. [DOI: 10.1080/02603599908012011] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Randaccio L, Geremia S, Nardin G, Šlouf M, Srnova I. Crystal Chemistry of Cobalamins. Structural Characterization of the Co−S Bond in Cobalamins. Inorg Chem 1999. [DOI: 10.1021/ic9903376] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Marques HM, Brown KL. The structure of cobalt corrinoids based on molecular mechanics and NOE-restrained molecular mechanics and dynamics simulations. Coord Chem Rev 1999. [DOI: 10.1016/s0010-8545(99)00074-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Randaccio L, Furlan M, Geremia S, Slouf M. Preparation and X-ray Analysis of Crystals of Azido- and Chlorocobalamin Containing LiCl: A Structural Model for the Interactions of the Corrin Ring with Ionic Species. Inorg Chem 1998. [DOI: 10.1021/ic980181u] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lucio Randaccio
- Dipartimento di Scienze Chimiche, Università di Trieste, I-34121 Trieste, Italy, and Sincrotrone Trieste SpA, Padriciano 99, 34100 Trieste, Italy
| | - Michela Furlan
- Dipartimento di Scienze Chimiche, Università di Trieste, I-34121 Trieste, Italy, and Sincrotrone Trieste SpA, Padriciano 99, 34100 Trieste, Italy
| | - Silvano Geremia
- Dipartimento di Scienze Chimiche, Università di Trieste, I-34121 Trieste, Italy, and Sincrotrone Trieste SpA, Padriciano 99, 34100 Trieste, Italy
| | - Miroslav Slouf
- Dipartimento di Scienze Chimiche, Università di Trieste, I-34121 Trieste, Italy, and Sincrotrone Trieste SpA, Padriciano 99, 34100 Trieste, Italy
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Brown KL, Zou X, Marques HM. NMR-restrained molecular modeling of cobalt corrinoids: cyanocobalamin (vitamin B12) and methylcobalt corrinoids. ACTA ACUST UNITED AC 1998. [DOI: 10.1016/s0166-1280(98)00206-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Brown KL, Cheng S, Zou X, Li J, Chen G, Valente EJ, Zubkowski JD, Marques HM. Structural and enzymatic studies of a new analogue of coenzyme B12 with an alpha-adenosyl upper axial ligand. Biochemistry 1998; 37:9704-15. [PMID: 9657683 DOI: 10.1021/bi980707m] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A new analogue of coenzyme B12 (5'-deoxyadenosylcobalamin, AdoCbl), in which the configuration of the N-glycosidic bond in the Ado ligand is inverted [(alpha-ribo)AdoCbl], has been synthesized and its crystal structure determined by X-ray diffraction [MoKalpha, lambda = 0.71073 A, monoclinic P212121, a = 16.132(12) A, b = 21. 684(15) A, c = 27.30(3) A, 9611 independent reflections, R1 = 0. 0708]. As suggested by molecular mechanics modeling before the structure was known, the Ado ligand lies over the southern quadrant of the molecule, as is the case for AdoCbl. The most striking feature of the structure is disorder in the orientation of the adenine (Ade) moiety relative to the ribose of the Ado ligand. This was resolved with a two-state model in which in the major (0.57 occupancy) conformer the A16(O)-A11-A9(N)-A8 dihedral angle is 1.9 degrees and the Ade is virtually perpendicular to the corrin ring; in the minor conformer, the Ade is tilted down, and this dihedral is -48.7 degrees. The Co-C and axial Co-N bond lengths and the Co-C-C bond angle are quite similar to those in AdoCbl. The corrin ring is considerably flatter than that of AdoCbl, with a fold angle of 11.7 degrees. The molecule was successfully modeled by molecular mechanics (MM), and rotation of the Ado ligand relative to the corrin gave rise to four locally minimum structures with the Ado in the southern, eastern, northern, or western quadrant, with the southern conformation as the global minimum, as is the case with AdoCbl itself. Nuclear Overhauser effects (nOe's) observed by two-dimensional (2D) NMR were incorporated as restraints in molecular dynamics (MD) and simulated annealing (SA) calculations. A MD simulation at 300 K showed that only the southern conformation is populated with the Ado ligand confined to an arc from over C15 to over C12, while the Ade ring oscillates from perpendicular to parallel to the corrin ring. Twenty-seven structures were collected by MD-SA. Most of these annealed into the southern conformation, but examples of the other conformations were also found. The new analogue is a partially active coenzyme for the ribonucleotide reductase from Lactobacillus leichmanii with maximal activity that is 9.7% of that of AdoCbl itself, and a very high Km value (245 microM compared to 0.54 microM for AdoCbl). In addition, the rate constant for enzyme-induced carbon-cobalt bond cleavage of (alpha-ribo)AdoCbl is 160-fold smaller than that for AdoCbl, and only 1/3 as much cob(II)alamin is produced at the active site.
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Affiliation(s)
- K L Brown
- Department of Chemistry, Ohio University, Athens 45701, USA.
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Brown KL, Cheng S, Marques HM. Conformational studies of 5′-deoxyadenosyl-13-epicobalamin, a coenzymatically active structural analog of coenzyme B12. Polyhedron 1998. [DOI: 10.1016/s0277-5387(98)00053-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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