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Ruetz M, Mascarenhas R, Widner F, Kieninger C, Koutmos M, Kräutler B, Banerjee R. A Noble Metal Substitution Leads to B 12 Cofactor Mimicry by a Rhodibalamin. Biochemistry 2024; 63:1955-1962. [PMID: 39012171 DOI: 10.1021/acs.biochem.4c00216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/17/2024]
Abstract
In mammals, cobalamin is an essential cofactor that is delivered by a multitude of chaperones in an elaborate trafficking pathway to two client enzymes, methionine synthase and methylmalonyl-CoA mutase (MMUT). Rhodibalamins, the rhodium analogs of cobalamins, have been described as antimetabolites due to their ability to inhibit bacterial growth. In this study, we have examined the reactivity of adenosylrhodibalamin (AdoRhbl) with two key human chaperones, MMACHC (also known as CblC) and adenosyltransferase (MMAB, also known as ATR), and with the human and Mycobacterium tuberculosis MMUT. We demonstrate that while AdoRhbl binds tightly to all four proteins, the Rh-carbon bond is resistant to homolytic (on MMAB and MMUT) as well as heterolytic (on MMACHC) rupture. On the other hand, MMAB catalyzes Rh-carbon bond formation, converting rhodi(I)balamin in the presence of ATP to AdoRhbl. We report the first crystal structure of a rhodibalamin (AdoRhbl) bound to a B12 protein, i.e., MMAB, in the presence of triphosphate, which shows a weakened but intact Rh-carbon bond. The structure provides insights into how MMAB cleaves the corresponding Co-carbon bond in a sacrificial homolytic reaction that purportedly functions as a cofactor sequestration strategy. Collectively, the study demonstrates that while the noble metal substitution of cobalt by rhodium sets up structural mimicry, it compromises chemistry, which could be exploited for targeting human and bacterial B12 chaperones and enzymes.
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2
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Simonenko SY, Bogdanova DA, Kuldyushev NA. Emerging Roles of Vitamin B 12 in Aging and Inflammation. Int J Mol Sci 2024; 25:5044. [PMID: 38732262 PMCID: PMC11084641 DOI: 10.3390/ijms25095044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Revised: 04/28/2024] [Accepted: 04/29/2024] [Indexed: 05/13/2024] Open
Abstract
Vitamin B12 (cobalamin) is an essential nutrient for humans and animals. Metabolically active forms of B12-methylcobalamin and 5-deoxyadenosylcobalamin are cofactors for the enzymes methionine synthase and mitochondrial methylmalonyl-CoA mutase. Malfunction of these enzymes due to a scarcity of vitamin B12 leads to disturbance of one-carbon metabolism and impaired mitochondrial function. A significant fraction of the population (up to 20%) is deficient in vitamin B12, with a higher rate of deficiency among elderly people. B12 deficiency is associated with numerous hallmarks of aging at the cellular and organismal levels. Cellular senescence is characterized by high levels of DNA damage by metabolic abnormalities, increased mitochondrial dysfunction, and disturbance of epigenetic regulation. B12 deficiency could be responsible for or play a crucial part in these disorders. In this review, we focus on a comprehensive analysis of molecular mechanisms through which vitamin B12 influences aging. We review new data about how deficiency in vitamin B12 may accelerate cellular aging. Despite indications that vitamin B12 has an important role in health and healthy aging, knowledge of the influence of vitamin B12 on aging is still limited and requires further research.
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Affiliation(s)
- Sergey Yu. Simonenko
- Research Center for Translational Medicine, Sirius University of Science and Technology, 354340 Sochi, Russia;
| | - Daria A. Bogdanova
- Division of Immunobiology and Biomedicine, Center for Genetics and Life Sciences, Sirius University of Science and Technology, 354340 Sochi, Russia
| | - Nikita A. Kuldyushev
- Research Center for Translational Medicine, Sirius University of Science and Technology, 354340 Sochi, Russia;
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3
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Fedosov SN, Nexo E, Heegaard CW. Kinetics of Cellular Cobalamin Uptake and Conversion: Comparison of Aquo/Hydroxocobalamin to Cyanocobalamin. Nutrients 2024; 16:378. [PMID: 38337663 PMCID: PMC10857013 DOI: 10.3390/nu16030378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 01/21/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024] Open
Abstract
Cyanocobalamin (CNCbl) and aquo/hydroxocobalamin (HOCbl) are the forms of vitamin B12 that are most commonly used for supplementation. They are both converted to methylcobalamin (MeCbl) and 5'-deoxyadenosylcobalamin (AdoCbl), which metabolize homocysteine and methylmalonic acid, respectively. Here, we compare the kinetics of uptake and the intracellular transformations of radiolabeled CNCbl vs. HOCbl in HeLa cells. More HOCbl was accumulated over 4-48 h, but further extrapolation indicated similar uptake (>90%) for both vitamin forms. The initially synthesized coenzyme was MeCbl, which noticeably exceeded AdoCbl during 48 h. Yet, the synthesis of AdoCbl accelerated, and the predicted final levels of Cbls were MeCbl ≈ AdoCbl ≈ 40% and HOCbl ≈ 20%. The designed kinetic model revealed the same patterns of the uptake and turnover for CNCbl and HOCbl, apart from two steps. First, the "activating" intracellular processing of the internalized HOCbl was six-fold faster. Second, the detachment rates from the cell surface (when the "excessive" Cbl-molecules were refluxed into the external medium) related as 4:1 for CNCbl vs. HOCbl. This gave a two-fold faster cellular accumulation and processing of HOCbl vs. CNCbl. In medical terms, our data suggest (i) an earlier response to the treatment of Cbl-deficiency with HOCbl, and (ii) the manifestation of a successful treatment initially as a decrease in homocysteine.
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Affiliation(s)
- Sergey N. Fedosov
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark;
- Department of Clinical Medicine/Clinical Biochemistry, Aarhus University Hospital, 8200 Aarhus N, Denmark;
| | - Ebba Nexo
- Department of Clinical Medicine/Clinical Biochemistry, Aarhus University Hospital, 8200 Aarhus N, Denmark;
| | - Christian W. Heegaard
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark;
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4
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Du M, Wu S, Su C, Wang X, Li B, Lin Y, Yuan S, Chen Y, Zhu C, Wei H. Serum Vitamin B12 is a Promising Auxiliary Index for the Diagnosis of Methylmalonic Acidemia in Children: A Single Center Study in China. Clin Chim Acta 2023; 546:117409. [PMID: 37217112 DOI: 10.1016/j.cca.2023.117409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/25/2023] [Accepted: 05/19/2023] [Indexed: 05/24/2023]
Abstract
BACKGROUND AND AIMS Vitamin B12 (cobalamin, VitB12) is an essential coenzyme of methylmalonyl-CoA mutase and methionine synthase. Variations in VitB12 metabolism, absorption, transport, or intake may cause changes in methylmalonic acidemia (MMA) biomarkers. We aimed to investigate whether serum Vitamin B12 levels could be used in the early detection of MMA. MATERIALS AND METHODS We included 241 children with MMA and 241 healthy matched controls. We measured serum VitB12 levels by an enzyme immunoassay and investigated the relationship between abnormal VitB12 levels and hematologic parameters as potential risk factors for MMA symptoms. RESULTS Compared with controls, the serum levels of VitB12 were increased in the MMA group (p < 0.001). Serum VitB12 distinguished patients with MMA from healthy children (p < 0.001). Serum VitB12 combined with homocysteine and ammonia identified cblC and mut type MMA, respectively (p < 0.001). Homocysteine, folate, ammonia, NLR, and red blood cells contributed to serum VitB12 in cblC type MMA (p < 0.001); homocysteine, ammonia, and red blood cells, contributed in mut type MMA (p < 0.001); and elevated VitB12 was an independent predictor of MMA clinical onset (p < 0.001). CONCLUSION Serum VitB12 can be used as an early diagnostic biomarker for MMA in children.
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Affiliation(s)
- Mengmeng Du
- Children's Hospital Affiliated to Zhengzhou University, Department of Endocrinology, Genetics and Metabolism, Henan Children's Hospital, Zhengz- hou Children's Hospital, Zhengzhou, China; Henan Key Laboratory of Child Brain Injury and Henan Pediatric Clinical Research Center, Third Affiliated Hospital and Institute of Neuroscience, Zhengzhou University, Zhengzhou, China.
| | - Shengnan Wu
- Children's Hospital Affiliated to Zhengzhou University, Department of Endocrinology, Genetics and Metabolism, Henan Children's Hospital, Zhengz- hou Children's Hospital, Zhengzhou, China.
| | - Chang Su
- Department of Endocrinology, Genetic and Metabolism, Beijing Children's Hospital, Capital Medical University, Beijing, China.
| | - Xiaohong Wang
- Children's Hospital Affiliated to Zhengzhou University, Department of Endocrinology, Genetics and Metabolism, Henan Children's Hospital, Zhengz- hou Children's Hospital, Zhengzhou, China.
| | - Bingbing Li
- Henan Key Laboratory of Child Brain Injury and Henan Pediatric Clinical Research Center, Third Affiliated Hospital and Institute of Neuroscience, Zhengzhou University, Zhengzhou, China.
| | - Yifan Lin
- Children's Hospital Affiliated to Zhengzhou University, Department of Endocrinology, Genetics and Metabolism, Henan Children's Hospital, Zhengz- hou Children's Hospital, Zhengzhou, China.
| | - Shuxian Yuan
- Children's Hospital Affiliated to Zhengzhou University, Department of Endocrinology, Genetics and Metabolism, Henan Children's Hospital, Zhengz- hou Children's Hospital, Zhengzhou, China.
| | - Yongxing Chen
- Children's Hospital Affiliated to Zhengzhou University, Department of Endocrinology, Genetics and Metabolism, Henan Children's Hospital, Zhengz- hou Children's Hospital, Zhengzhou, China.
| | - Changlian Zhu
- Children's Hospital Affiliated to Zhengzhou University, Department of Endocrinology, Genetics and Metabolism, Henan Children's Hospital, Zhengz- hou Children's Hospital, Zhengzhou, China; Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology, University of Gothenburg, Sweden.
| | - Haiyan Wei
- Children's Hospital Affiliated to Zhengzhou University, Department of Endocrinology, Genetics and Metabolism, Henan Children's Hospital, Zhengz- hou Children's Hospital, Zhengzhou, China.
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5
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Gouda H, Mascarenhas R, Ruetz M, Yaw M, Banerjee R. Bivalent molecular mimicry by ADP protects metal redox state and promotes coenzyme B 12 repair. Proc Natl Acad Sci U S A 2023; 120:e2220677120. [PMID: 36888659 PMCID: PMC10243129 DOI: 10.1073/pnas.2220677120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 02/07/2023] [Indexed: 03/09/2023] Open
Abstract
Control over transition metal redox state is essential for metalloprotein function and can be achieved via coordination chemistry and/or sequestration from bulk solvent. Human methylmalonyl-Coenzyme A (CoA) mutase (MCM) catalyzes the isomerization of methylmalonyl-CoA to succinyl-CoA using 5'-deoxyadenosylcobalamin (AdoCbl) as a metallocofactor. During catalysis, the occasional escape of the 5'-deoxyadenosine (dAdo) moiety leaves the cob(II)alamin intermediate stranded and prone to hyperoxidation to hydroxocobalamin, which is recalcitrant to repair. In this study, we have identified the use of bivalent molecular mimicry by ADP, coopting the 5'-deoxyadenosine and diphosphate moieties in the cofactor and substrate, respectively, to protect against cob(II)alamin overoxidation on MCM. Crystallographic and electron paramagnetic resonance (EPR) data reveal that ADP exerts control over the metal oxidation state by inducing a conformational change that seals off solvent access, rather than by switching five-coordinate cob(II)alamin to the more air stable four-coordinate state. Subsequent binding of methylmalonyl-CoA (or CoA) promotes cob(II)alamin off-loading from MCM to adenosyltransferase for repair. This study identifies an unconventional strategy for controlling metal redox state by an abundant metabolite to plug active site access, which is key to preserving and recycling a rare, but essential, metal cofactor.
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Affiliation(s)
- Harsha Gouda
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI48109
| | - Romila Mascarenhas
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI48109
| | - Markus Ruetz
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI48109
| | - Madeline Yaw
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI48109
| | - Ruma Banerjee
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI48109
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6
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Esser AJ, Mukherjee S, Dereven‘kov IA, Makarov SV, Jacobsen DW, Spiekerkoetter U, Hannibal L. Versatile Enzymology and Heterogeneous Phenotypes in Cobalamin Complementation Type C Disease. iScience 2022; 25:104981. [PMID: 36105582 PMCID: PMC9464900 DOI: 10.1016/j.isci.2022.104981] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Nutritional deficiency and genetic errors that impair the transport, absorption, and utilization of vitamin B12 (B12) lead to hematological and neurological manifestations. The cblC disease (cobalamin complementation type C) is an autosomal recessive disorder caused by mutations and epi-mutations in the MMACHC gene and the most common inborn error of B12 metabolism. Pathogenic mutations in MMACHC disrupt enzymatic processing of B12, an indispensable step before micronutrient utilization by the two B12-dependent enzymes methionine synthase (MS) and methylmalonyl-CoA mutase (MUT). As a result, patients with cblC disease exhibit plasma elevation of homocysteine (Hcy, substrate of MS) and methylmalonic acid (MMA, degradation product of methylmalonyl-CoA, substrate of MUT). The cblC disorder manifests early in childhood or in late adulthood with heterogeneous multi-organ involvement. This review covers current knowledge on the cblC disease, structure–function relationships of the MMACHC protein, the genotypic and phenotypic spectra in humans, experimental disease models, and promising therapies.
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7
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Passantino R, Mangione MR, Ortore MG, Costa MA, Provenzano A, Amenitsch H, Sabbatella R, Alfano C, Martorana V, Vilasi S. Investigation on a MMACHC mutant from cblC disease: The c.394C>T variant. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2022; 1870:140793. [PMID: 35618206 DOI: 10.1016/j.bbapap.2022.140793] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 05/17/2022] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
The cblC disease is an inborn disorder of the vitamin B12 (cobalamin, Cbl) metabolism characterized by methylmalonic aciduria and homocystinuria. The clinical consequences of this disease are devastating and, even when early treated with current therapies, the affected children manifest symptoms involving vision, growth, and learning. The illness is caused by mutations in the gene codifying for MMACHC, a 282aa protein that transports and transforms the different Cbl forms. Here we present data on the structural properties of the truncated protein p.R132X resulting from the c.394C > T mutation that, along with c.271dupA and c.331C > T, is among the most common mutations in cblC. Although missing part of the Cbl binding domain, p.R132X is associated to late-onset symptoms and, therefore, it is supposed to retain residual function. However, to our knowledge structural-functional studies on c.394C > T mutant aimed at verifying this hypothesis are still lacking. By using a biophysical approach including Circular Dichroism, fluorescence, Small Angle X-ray Scattering, and Molecular Dynamics, we show that the mutant protein MMACHC-R132X retains secondary structure elements and remains compact in solution, partly preserving its binding affinity for Cbl. Insights on the fragile stability of MMACHC-R132X-Cbl are provided.
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Affiliation(s)
- Rosa Passantino
- Biophysics Institute, National Research Council, Palermo 90143, Italy
| | | | - Maria Grazia Ortore
- Dept. Life and Environmental Sciences, Marche Polytechnic University, Ancona 60131, Italy
| | | | | | | | | | | | | | - Silvia Vilasi
- Biophysics Institute, National Research Council, Palermo 90143, Italy.
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8
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Kiessling E, Peters F, Ebner LJ, Merolla L, Samardzija M, Baumgartner MR, Grimm C, Froese DS. HIF1 and DROSHA are involved in MMACHC repression in hypoxia. Biochim Biophys Acta Gen Subj 2022; 1866:130175. [DOI: 10.1016/j.bbagen.2022.130175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 05/03/2022] [Accepted: 05/23/2022] [Indexed: 11/25/2022]
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9
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Structural Study of the Complex of cblC Methylmalonic Aciduria and Homocystinuria-Related Protein MMACHC with Cyanocobalamin. CRYSTALS 2022. [DOI: 10.3390/cryst12040468] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
MMACHC is an essential protein for the body to metabolise vitamin B12, and its deficiency will cause cblC-type methylmalonic aciduria and homocystinuria. MMACHC can interact with cyanocobalamin (a type of vitamin B12) cofactor and plays an important role in targeting cyanocobalamin to the enzyme of interest. In this paper, the GST-tag fusion-tagged MMACHC protein was successfully expressed by Escherichia coli (E. coli) low-temperature induction, and the high-purity MMACHC protein was successfully purified by affinity chromatography and gel filtration. Further, the crystal structure of MMACHC and cyanocobalamin complex was obtained with a resolution of 1.93 Å using X-ray diffraction. By analysing the complex structure of MMACHC and cyanocobalamin, we revealed the reasons for the diversity of MMACHC substrates and explained the reasons for the differences in disease conditions caused by different MMACHC site mutations. The acquisition of the complex structure of MMACHC and cyanocobalamin will play a significant role in promoting research on the metabolic pathway of vitamin B12.
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10
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Hannibal L, Jacobsen DW. Intracellular processing of vitamin B 12 by MMACHC (CblC). VITAMINS AND HORMONES 2022; 119:275-298. [PMID: 35337623 DOI: 10.1016/bs.vh.2022.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Vitamin B12 (cobalamin, Cbl, B12) is a water-soluble micronutrient synthesized exclusively by a group of microorganisms. Human beings are unable to make B12 and thus obtain the vitamin via intake of animal products, fermented plant-based foods or supplements. Vitamin B12 obtained from the diet comprises three major chemical forms, namely hydroxocobalamin (HOCbl), methylcobalamin (MeCbl) and adenosylcobalamin (AdoCbl). The most common form of B12 present in supplements is cyanocobalamin (CNCbl). Yet, these chemical forms cannot be utilized directly as they come, but instead, they undergo chemical processing by the MMACHC protein, also known as CblC. Processing of dietary B12 by CblC involves removal of the upper-axial ligand (beta-ligand) yielding the one-electron reduced intermediate cob(II)alamin. Newly formed cob(II)alamin undergoes trafficking and delivery to the two B12-dependent enzymes, cytosolic methionine synthase (MS) and mitochondrial methylmalonyl-CoA mutase (MUT). The catalytic cycles of MS and MUT incorporate cob(II)alamin as a precursor to regenerate the coenzyme forms MeCbl and AdoCbl, respectively. Mutations and epimutations in the MMACHC gene result in cblC disease, the most common inborn error of B12 metabolism, which manifests with combined homocystinuria and methylmalonic aciduria. Elevation of metabolites homocysteine and methylmalonic acid occurs because the lack of an active CblC blocks formation of the indispensable precursor cob(II)alamin that is necessary to activate MS and MUT. Thus, in patients with cblC disease, vitamin B12 is absorbed and present in circulation in normal to high concentrations, yet, cells are unable to make use of it. Mutations in seemingly unrelated genes that modify MMACHC gene expression also result in clinical phenotypes that resemble cblC disease. We review current knowledge on structural and functional aspects of intracellular processing of vitamin B12 by the versatile protein CblC, its partners and possible regulators.
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Affiliation(s)
- Luciana Hannibal
- Laboratory of Clinical Biochemistry and Metabolism, Department of General Pediatrics, Adolescent Medicine and Neonatology, Faculty of Medicine, Medical Center-University of Freiburg, Freiburg, Germany.
| | - Donald W Jacobsen
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
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11
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Affiliation(s)
- Bernhard Kräutler
- Institute of Organic Chemistry and Centre of Molecular Biosciences, University of Innsbruck, Innsbruck, Austria.
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12
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Ruetz M, Koutmos M, Kräutler B. Antivitamins B 12: Synthesis and application as inhibitory ligand of the B 12-tailoring enzyme CblC. Methods Enzymol 2022; 668:157-178. [PMID: 35589193 DOI: 10.1016/bs.mie.2021.12.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Antivitamins B12 are non-natural corrinoids that have been designed to counteract the metabolic effects of vitamin B12 and related cobalamins (Cbls) in humans and other mammals. A basic structure- and reactivity-based concept typifies antivitamins B12 as close structural mimics of vitamin B12 that are not transformed by the cellular metabolism into organometallic B12-cofactors. Antivitamins B12 have the correct structure for efficient take-up and transport via the natural mammalian pathway for cobalamin assimilation. Thus they can be delivered to every cell in the body, where they are proposed to target and inhibit the Cbl tailoring enzyme CblC. Antivitamins B12 may be specifically inert Cbls or isostructural Cbl-analogues that carry a metal centre other than a cobalt-ion. The syntheses of two antivitamins B12 are detailed here, as are biochemical and crystallographic studies that provide insights into the crucial binding interactions of Cbl-based antivitamins B12 with the human B12-tailoring enzyme CblC. This key enzyme binds genuine antivitamins B12 as inert substrate mimics and enzyme inhibitors, effectively repressing the metabolic generation of the B12-cofactors. Hence, antivitamins B12 induce the diagnostic symptoms of (functional) B12-deficiency, as observed in healthy laboratory mice.
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Affiliation(s)
- Markus Ruetz
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Markos Koutmos
- Department of Chemistry, Program in Biophysics, Program in Chemical Biology, University of Michigan, Ann Arbor, MI, United States.
| | - Bernhard Kräutler
- Institute of Organic Chemistry and Center of Molecular Biosciences, University of Innsbruck, Innsbruck, Austria.
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13
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Chern T, Achilleos A, Tong X, Hill MC, Saltzman AB, Reineke LC, Chaudhury A, Dasgupta SK, Redhead Y, Watkins D, Neilson JR, Thiagarajan P, Green JBA, Malovannaya A, Martin JF, Rosenblatt DS, Poché RA. Mutations in Hcfc1 and Ronin result in an inborn error of cobalamin metabolism and ribosomopathy. Nat Commun 2022; 13:134. [PMID: 35013307 PMCID: PMC8748873 DOI: 10.1038/s41467-021-27759-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 12/13/2021] [Indexed: 12/26/2022] Open
Abstract
Combined methylmalonic acidemia and homocystinuria (cblC) is the most common inborn error of intracellular cobalamin metabolism and due to mutations in Methylmalonic Aciduria type C and Homocystinuria (MMACHC). Recently, mutations in the transcriptional regulators HCFC1 and RONIN (THAP11) were shown to result in cellular phenocopies of cblC. Since HCFC1/RONIN jointly regulate MMACHC, patients with mutations in these factors suffer from reduced MMACHC expression and exhibit a cblC-like disease. However, additional de-regulated genes and the resulting pathophysiology is unknown. Therefore, we have generated mouse models of this disease. In addition to exhibiting loss of Mmachc, metabolic perturbations, and developmental defects previously observed in cblC, we uncovered reduced expression of target genes that encode ribosome protein subunits. We also identified specific phenotypes that we ascribe to deregulation of ribosome biogenesis impacting normal translation during development. These findings identify HCFC1/RONIN as transcriptional regulators of ribosome biogenesis during development and their mutation results in complex syndromes exhibiting aspects of both cblC and ribosomopathies. Combined methylmalonic acidemia (MMA) and hyperhomocysteinemias are inborn errors of vitamin B12 metabolism, and mutations in the transcriptional regulators HCFC1 and RONIN (THAP11) underlie some forms of these disorders. Here the authors generated mouse models of a human syndrome due to mutations in RONIN (THAP11) and HCFC1, and show that this syndrome is both an inborn error of vitamin B12 metabolism and displays some features of ribosomopathy.
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Affiliation(s)
- Tiffany Chern
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA.,Graduate Program in Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Annita Achilleos
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Basic and Clinical Sciences, University of Nicosia Medical School, Nicosia, Cyprus.
| | - Xuefei Tong
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Matthew C Hill
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA.,Graduate Program in Developmental Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Alexander B Saltzman
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Lucas C Reineke
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Arindam Chaudhury
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Swapan K Dasgupta
- Department of Pathology, Center for Translational Research on Inflammatory Diseases, Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX, 77030, USA
| | - Yushi Redhead
- The Francis Crick Institute, London, NW1 1AT, UK.,Centre for Craniofacial Biology and Regeneration, King's College London, London, SE1 9RT, UK
| | - David Watkins
- Division of Medical Genetics, Department of Specialized Medicine, McGill University Health Centre, Montreal, QC, Canada.,Division of Medical Biochemistry, Department of Specialized Medicine, McGill University Health Centre, Montreal, QC, Canada
| | - Joel R Neilson
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA.,Graduate Program in Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA.,Development, Disease Models and Therapeutics Graduate Program, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Perumal Thiagarajan
- Department of Pathology, Center for Translational Research on Inflammatory Diseases, Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX, 77030, USA.,Department of Medicine, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Jeremy B A Green
- Centre for Craniofacial Biology and Regeneration, King's College London, London, SE1 9RT, UK
| | - Anna Malovannaya
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - James F Martin
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA.,Graduate Program in Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA.,Graduate Program in Developmental Biology, Baylor College of Medicine, Houston, TX, 77030, USA.,Development, Disease Models and Therapeutics Graduate Program, Baylor College of Medicine, Houston, TX, 77030, USA.,Texas Heart Institute, Houston, TX, 77030, USA
| | - David S Rosenblatt
- Division of Medical Genetics, Department of Specialized Medicine, McGill University Health Centre, Montreal, QC, Canada.,Division of Medical Biochemistry, Department of Specialized Medicine, McGill University Health Centre, Montreal, QC, Canada.,Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Ross A Poché
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA. .,Graduate Program in Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA. .,Graduate Program in Developmental Biology, Baylor College of Medicine, Houston, TX, 77030, USA. .,Development, Disease Models and Therapeutics Graduate Program, Baylor College of Medicine, Houston, TX, 77030, USA.
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14
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Vaccaro JA, Naser SA. The Role of Methyl Donors of the Methionine Cycle in Gastrointestinal Infection and Inflammation. Healthcare (Basel) 2021; 10:healthcare10010061. [PMID: 35052225 PMCID: PMC8775811 DOI: 10.3390/healthcare10010061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/21/2021] [Accepted: 12/27/2021] [Indexed: 12/01/2022] Open
Abstract
Vitamin deficiency is well known to contribute to disease development in both humans and other animals. Nonetheless, truly understanding the role of vitamins in human biology requires more than identifying their deficiencies. Discerning the mechanisms by which vitamins participate in health is necessary to assess risk factors, diagnostics, and treatment options for deficiency in a clinical setting. For researchers, the absence of a vitamin may be used as a tool to understand the importance of the metabolic pathways in which it participates. This review aims to explore the current understanding of the complex relationship between the methyl donating vitamins folate and cobalamin (B12), the universal methyl donor S-adenosyl-L-methionine (SAM), and inflammatory processes in human disease. First, it outlines the process of single-carbon metabolism in the generation of first methionine and subsequently SAM. Following this, established relationships between folate, B12, and SAM in varying bodily tissues are discussed, with special attention given to their effects on gut inflammation.
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15
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Fan D, Zhang Y, Wu H. Development of a simple and sensitive HPLC-DAD method for quantification of vitamin B12 fortified in infant food. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2021; 13:4920-4925. [PMID: 34609384 DOI: 10.1039/d1ay01118a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
To prevent infants from vitamin B12 deficiency, infant food is designed based on cow's milk or cereal with the fortification of vitamin B12. A method for quantitative determination of vitamin B12 in infant food was developed with hydrophilic high performance liquid chromatography (HPLC) coupled with a diode array detector (DAD). The sensitivity of the detector was enhanced by implementing a 60 mm high-sensitivity LightPipe flow cell, and the limit of detection (LOD) and limit of quantification (LOQ) were improved as low as 0.006 μg 100 g-1 and 0.02 μg 100 g-1 respectively. The effect of sample extraction and enrichment, chromatography separation parameters on the analyte, were studied in detail and optimized. Under these conditions, the method performed a good linear analytical range of 0.3-50 μg L-1, and a good repeatability with % RSD below 2.8% and recovery of 90.2-96.5% (n = 6). To the best of our knowledge, for the first time, 60 mm high-sensitivity LightPipe flow cell was included in the HPLC-DAD method for determination of the trace amount of vitamin B12 in infant food. The proposed method was further validated by analysis of FAPAS QC samples (T21120 and T21118), and it was specific and precise for the intended use.
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Affiliation(s)
- Dingyan Fan
- Research and Development Department, GRA (Shanghai) Standard Technology Service Co., Ltd, Shanghai 201318, P. R. China.
| | - Yingzhou Zhang
- Research and Development Department, GRA (Shanghai) Standard Technology Service Co., Ltd, Shanghai 201318, P. R. China.
| | - Haiping Wu
- Research and Development Department, GRA (Shanghai) Standard Technology Service Co., Ltd, Shanghai 201318, P. R. China.
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16
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Matmat K, Guéant-Rodriguez RM, Oussalah A, Wiedemann-Fodé A, Dionisi-Vici C, Coelho D, Guéant JL, Conart JB. Ocular manifestations in patients with inborn errors of intracellular cobalamin metabolism: a systematic review. Hum Genet 2021; 141:1239-1251. [PMID: 34652574 DOI: 10.1007/s00439-021-02350-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 08/19/2021] [Indexed: 01/26/2023]
Abstract
Inherited disorders of cobalamin (cbl) metabolism (cblA-J) result in accumulation of methylmalonic acid (MMA) and/or homocystinuria (HCU). Clinical presentation includes ophthalmological manifestations related to retina, optic nerve and posterior visual alterations, mainly reported in cblC and sporadically in other cbl inborn errors.We searched MEDLINE EMBASE and Cochrane Library, and analyzed articles reporting ocular manifestations in cbl inborn errors. Out of 166 studies a total of 52 studies reporting 163 cbl and 24 mut cases were included. Ocular manifestations were found in all cbl defects except for cblB and cblD-MMA; cblC was the most frequent disorder affecting 137 (84.0%) patients. The c.271dupA was the most common pathogenic variant, accounting for 70/105 (66.7%) cases. One hundred and thirty-seven out of 154 (88.9%) patients presented with early-onset disease (0-12 months). Nystagmus and strabismus were observed in all groups with the exception of MMA patients while maculopathy and peripheral retinal degeneration were almost exclusively found in MMA-HCU patients. Optic nerve damage ranging from mild temporal disc pallor to complete atrophy was prevalent in MMA-HCU.and MMA groups. Nystagmus was frequent in early-onset patients. Retinal and macular degeneration worsened despite early treatment and stabilized systemic function in these patients. The functional prognosis remains poor with final visual acuity < 20/200 in 55.6% (25/45) of cases. In conclusion, the spectrum of eye disease in Cbl patients depends on metabolic severity and age of onset. The development of visual manifestations over time despite early metabolic treatment point out the need for specific innovative therapies.
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Affiliation(s)
- Karim Matmat
- UMR_S 1256, NGERE - Nutrition, Genetics, and Environmental Risk Exposure, INSERM, University of Lorraine, 54000, Nancy, France
| | - Rosa-Maria Guéant-Rodriguez
- UMR_S 1256, NGERE - Nutrition, Genetics, and Environmental Risk Exposure, INSERM, University of Lorraine, 54000, Nancy, France.
- National Center of Inborn Errors of Metabolism, University Regional Hospital Center of Nancy, 54000, Nancy, France.
| | - Abderrahim Oussalah
- UMR_S 1256, NGERE - Nutrition, Genetics, and Environmental Risk Exposure, INSERM, University of Lorraine, 54000, Nancy, France
- National Center of Inborn Errors of Metabolism, University Regional Hospital Center of Nancy, 54000, Nancy, France
| | - Arnaud Wiedemann-Fodé
- UMR_S 1256, NGERE - Nutrition, Genetics, and Environmental Risk Exposure, INSERM, University of Lorraine, 54000, Nancy, France
| | - Carlo Dionisi-Vici
- Division of Metabolism, Bambino Gesù Children's Hospital IRCCS, Piazza S. Onofrio 4, 00165, Rome, Italy
| | - David Coelho
- UMR_S 1256, NGERE - Nutrition, Genetics, and Environmental Risk Exposure, INSERM, University of Lorraine, 54000, Nancy, France
| | - Jean-Louis Guéant
- UMR_S 1256, NGERE - Nutrition, Genetics, and Environmental Risk Exposure, INSERM, University of Lorraine, 54000, Nancy, France
- National Center of Inborn Errors of Metabolism, University Regional Hospital Center of Nancy, 54000, Nancy, France
| | - Jean-Baptiste Conart
- UMR_S 1256, NGERE - Nutrition, Genetics, and Environmental Risk Exposure, INSERM, University of Lorraine, 54000, Nancy, France.
- Department of Ophthalmology, Nancy University Hospital, 54500, Vandœuvre-lès-Nancy, France.
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17
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Dereven’kov IA, Ugodin KA, Makarov SV. Mechanism of the Reaction between Cyanocobalamin and Reduced Flavin Mononucleotide. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2021. [DOI: 10.1134/s003602442110006x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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18
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Sobczyńska-Malefora A, Delvin E, McCaddon A, Ahmadi KR, Harrington DJ. Vitamin B 12 status in health and disease: a critical review. Diagnosis of deficiency and insufficiency - clinical and laboratory pitfalls. Crit Rev Clin Lab Sci 2021; 58:399-429. [PMID: 33881359 DOI: 10.1080/10408363.2021.1885339] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Vitamin B12 (cobalamin) is an essential cofactor for two metabolic pathways. It is obtained principally from food of animal origin. Cobalamin becomes bioavailable through a series of steps pertaining to its release from dietary protein, intrinsic factor-mediated absorption, haptocorrin or transcobalamin-mediated transport, cellular uptake, and two enzymatic conversions (via methionine synthase and methylmalonyl-CoA-mutase) into cofactor forms: methylcobalamin and adenosylcobalamin. Vitamin B12 deficiency can masquerade as a multitude of illnesses, presenting different perspectives from the point of view of the hematologist, neurologist, gastroenterologist, general physician, or dietician. Increased physician vigilance and heightened patient awareness often account for its early presentation, and testing sometimes occurs during a phase of vitamin B12 insufficiency before the main onset of the disease. The chosen test often depends on its availability rather than on the diagnostic performance and sensitivity to irrelevant factors interfering with vitamin B12 markers. Although serum B12 is still the most commonly used and widely available test, diagnostics by holotranscobalamin, serum methylmalonic acid, and plasma homocysteine measurements have grown in the last several years in routine practice. The lack of a robust absorption test, coupled with compromised sensitivity and specificity of other tests (intrinsic factor and gastric parietal cell antibodies), hinders determination of the cause for depleted B12 status. This can lead to incorrect supplementation regimes and uncertainty regarding later treatment. This review discusses currently available knowledge on vitamin B12, informs the reader about the pitfalls of tests for assessing its deficiency, reviews B12 status in various populations at different disease stages, and provides recommendations for interpretation, treatment, and associated risks. Future directions for diagnostics of B12 status and health interventions are also discussed.
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Affiliation(s)
- Agata Sobczyńska-Malefora
- The Nutristasis Unit, Viapath, St. Thomas' Hospital, London, UK.,Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Edgard Delvin
- Sainte-Justine UHC Research Centre, Montreal, Canada.,Department of Biochemistry and Molecular Medicine, University of Montreal, Montreal, Canada
| | | | - Kourosh R Ahmadi
- Department of Nutrition & Metabolism, School of Biosciences and Medicine, University of Surrey, Guildford, UK
| | - Dominic J Harrington
- The Nutristasis Unit, Viapath, St. Thomas' Hospital, London, UK.,Faculty of Life Sciences and Medicine, King's College London, London, UK
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19
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Banerjee R, Gouda H, Pillay S. Redox-Linked Coordination Chemistry Directs Vitamin B 12 Trafficking. Acc Chem Res 2021; 54:2003-2013. [PMID: 33797888 DOI: 10.1021/acs.accounts.1c00083] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Metals are partners for an estimated one-third of the proteome and vary in complexity from mononuclear centers to organometallic cofactors. Vitamin B12 or cobalamin represents the epitome of this complexity and is the product of an assembly line comprising some 30 enzymes. Unable to biosynthesize cobalamin, mammals rely on dietary provision of this essential cofactor, which is needed by just two enzymes, one each in the cytoplasm (methionine synthase) and the mitochondrion (methylmalonyl-CoA mutase). Brilliant clinical genetics studies on patients with inborn errors of cobalamin metabolism spanning several decades had identified at least seven genetic loci in addition to the two encoding B12 enzymes. While cells are known to house a cadre of chaperones dedicated to metal trafficking pathways that contain metal reactivity and confer targeting specificity, the seemingly supernumerary chaperones in the B12 pathway had raised obvious questions as to the rationale for their existence.With the discovery of the genes underlying cobalamin disorders, our laboratory has been at the forefront of ascribing functions to B12 chaperones and elucidating the intricate redox-linked coordination chemistry and protein-linked cofactor conformational dynamics that orchestrate the processing and translocation of cargo along the trafficking pathway. These studies have uncovered novel chemistry that exploits the innate chemical versatility of alkylcobalamins, i.e., the ability to form and dismantle the cobalt-carbon bond using homolytic or heterolytic chemistry. In addition, they have revealed the practical utility of the dimethylbenzimidazole tail, an appendage unique to cobalamins and absent in the structural cousins, porphyrin, chlorin, and corphin, as an instrument for facilitating cofactor transfer between active sites.In this Account, we navigate the chemistry of the B12 trafficking pathway from its point of entry into cells, through lysosomes, and into the cytoplasm, where incoming cobalamin derivatives with a diversity of upper ligands are denuded by the β-ligand transferase activity of CblC to the common cob(II)alamin intermediate. The broad reaction and lax substrate specificity of CblC also enables conversion of cyanocobalamin (technically, vitamin B12, i.e., the form of the cofactor in one-a-day supplements), to cob(II)alamin. CblD then hitches up with CblC via a unique Co-sulfur bond to cob(II)alamin at a bifurcation point, leading to the cytoplasmic methylcobalamin or mitochondrial 5'-deoxyadenosylcobalamin branch. Mutations at loci upstream of the junction point typically affect both branches, leading to homocystinuria and methylmalonic aciduria, whereas mutations in downstream loci lead to one or the other disease. Elucidation of the biochemical penalties associated with individual mutations is providing molecular insights into the clinical data and, in some instances, identifying which cobalamin derivative(s) might be therapeutically beneficial.Our studies on B12 trafficking are revealing strategies for cofactor sequestration and mobilization from low- to high-affinity and low- to high-coordination-number sites, which in turn are regulated by protein dynamics that constructs ergonomic cofactor binding pockets. While these B12 lessons might be broadly relevant to other metal trafficking pathways, much remains to be learned. This Account concludes by identifying some of the major gaps and challenges that are needed to complete our understanding of B12 trafficking.
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Affiliation(s)
- Ruma Banerjee
- Department of Biological Chemistry, Michigan Medicine, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Harsha Gouda
- Department of Biological Chemistry, Michigan Medicine, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Shubhadra Pillay
- Department of Biological Chemistry, Michigan Medicine, University of Michigan, Ann Arbor, Michigan 48109, United States
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20
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Orłowska M, Steczkiewicz K, Muszewska A. Utilization of cobalamin is ubiquitous in early-branching fungal phyla. Genome Biol Evol 2021; 13:6157828. [PMID: 33682003 PMCID: PMC8085122 DOI: 10.1093/gbe/evab043] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 02/15/2021] [Accepted: 03/01/2021] [Indexed: 12/19/2022] Open
Abstract
Cobalamin is a cofactor present in essential metabolic pathways in animals and one of the water-soluble vitamins. It is a complex compound synthesized solely by prokaryotes. Cobalamin dependence is scattered across the tree of life. In particular, fungi and plants were deemed devoid of cobalamin. We demonstrate that cobalamin is utilized by all non-Dikarya fungi lineages. This observation is supported by the genomic presence of both B12-dependent enzymes and cobalamin modifying enzymes. Fungal cobalamin-dependent enzymes are highly similar to their animal homologs. Phylogenetic analyses support a scenario of vertical inheritance of the cobalamin usage with several losses. Cobalamin usage was probably lost in Mucorinae and at the base of Dikarya which groups most of the model organisms and which hindered B12-dependent metabolism discovery in fungi. Our results indicate that cobalamin dependence was a widely distributed trait at least in Opisthokonta, across diverse microbial eukaryotes and was likely present in the LECA.
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Affiliation(s)
- Małgorzata Orłowska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland
| | - Kamil Steczkiewicz
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland
| | - Anna Muszewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland
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21
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Li Z, Mascarenhas R, Twahir UT, Kallon A, Deb A, Yaw M, Penner-Hahn J, Koutmos M, Warncke K, Banerjee R. An Interprotein Co-S Coordination Complex in the B 12-Trafficking Pathway. J Am Chem Soc 2020; 142:16334-16345. [PMID: 32871076 DOI: 10.1021/jacs.0c06590] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The CblC and CblD chaperones are involved in early steps in the cobalamin trafficking pathway. Cobalamin derivatives entering the cytoplasm are converted by CblC to a common cob(II)alamin intermediate via glutathione-dependent alkyltransferase or reductive elimination activities. Cob(II)alamin is subsequently converted to one of two biologically active alkylcobalamins by downstream chaperones. The function of CblD has been elusive although it is known to form a complex with CblC under certain conditions. Here, we report that CblD provides a sulfur ligand to cob(II)alamin bound to CblC, forming an interprotein coordination complex that rapidly oxidizes to thiolato-cob(III)alamin. Cysteine scanning mutagenesis and EPR spectroscopy identified Cys-261 on CblD as the sulfur donor. The unusual interprotein Co-S bond was characterized by X-ray absorption spectroscopy and visualized in the crystal structure of the human CblD thiolato-cob(III)alamin complex. Our study provides insights into how cobalamin coordination chemistry could be utilized for cofactor translocation in the trafficking pathway.
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Affiliation(s)
- Zhu Li
- Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600, United States
| | - Romila Mascarenhas
- Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600, United States
| | - Umar T Twahir
- Department of Physics, Emory University, Atlanta, Georgia 30322-2430, United States
| | - Albert Kallon
- Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600, United States
| | - Aniruddha Deb
- Departments of Chemistry and Biophysics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Madeline Yaw
- Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600, United States
| | - James Penner-Hahn
- Departments of Chemistry and Biophysics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Markos Koutmos
- Departments of Chemistry and Biophysics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Kurt Warncke
- Department of Physics, Emory University, Atlanta, Georgia 30322-2430, United States
| | - Ruma Banerjee
- Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600, United States
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22
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Chern T, Achilleos A, Tong X, Hsu CW, Wong L, Poché RA. Mouse models to study the pathophysiology of combined methylmalonic acidemia and homocystinuria, cblC type. Dev Biol 2020; 468:1-13. [PMID: 32941884 DOI: 10.1016/j.ydbio.2020.09.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 09/08/2020] [Accepted: 09/09/2020] [Indexed: 02/06/2023]
Abstract
Combined methylmalonic acidemia and homocystinuria, cblC type, is the most common inherited disorder of cobalamin metabolism and is characterized by severe fetal developmental defects primarily impacting the central nervous system, hematopoietic system, and heart. CblC was previously shown to be due to mutations in the MMACHC gene, which encodes a protein thought to function in intracellular cobalamin trafficking and biosynthesis of adenosylcobalamin (AdoCbl) and methylcobalamin (MeCbl). These coenzymes are required for the production of succinyl-CoA and methionine, respectively. However, it is currently unclear whether additional roles for MMACHC exist outside of cobalamin metabolism. Furthermore, due to a lack of sufficient animal models, the exact pathophysiology of cblC remains unknown. Here, we report the generation and characterization of two new mouse models to study the role of MMACHC in vivo. CRISPR/Cas9 genome editing was used to develop a Mmachc floxed allele (Mmachcflox/flox), which we validated as a conditional null. For a gain-of-function approach, we generated a transgenic mouse line that over-expresses functional Mmachc (Mmachc-OE+/tg) capable of rescuing Mmachc homozygous mutant lethality. Surprisingly, our data also suggest that these mice may exhibit a partially penetrant maternal-effect rescue, which might have implications for in utero therapeutic interventions to treat cblC. Both the Mmachcflox/flox and Mmachc-OE+/tg mouse models will be valuable resources for understanding the biological roles of MMACHC in a variety of tissue contexts and allow for deeper understanding of the pathophysiology of cblC.
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Affiliation(s)
- Tiffany Chern
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA; Graduate Program in Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Annita Achilleos
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Xuefei Tong
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Chih-Wei Hsu
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Leeyean Wong
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ross A Poché
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA; Graduate Program in Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA; Development, Disease Models and Therapeutics Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA; Genetics and Genomics Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA.
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23
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Castro VL, Quintana AM. The role of HCFC1 in syndromic and non-syndromic intellectual disability. ACTA ACUST UNITED AC 2020; 8. [PMID: 34164576 DOI: 10.18103/mra.v8i6.2122] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mutations in the HCFC1 gene are associated with cases of syndromic (cblX) and non-syndromic intellectual disability. Syndromic individuals present with severe neurological defects including intractable epilepsy, facial dysmorphia, and intellectual disability. Non-syndromic individuals have also been described and implicate a role for HCFC1 during brain development. The penetrance of phenotypes and the presence of an overall syndrome is associated with the location of the mutation within the HCFC1 protein. Thus, one could hypothesize that the positioning of HCFC1 mutations lead to different neurological phenotypes that include but are not restricted to intellectual disability. The HCFC1 protein is comprised of multiple domains that function in cellular proliferation/metabolism. Several reports of HCFC1 disease variants have been identified, but a comprehensive review of each variant and its associated phenotypes has not yet been compiled. Here we perform a detailed review of HCFC1 function, model systems, variant location, and accompanying phenotypes to highlight current knowledge and the future status of the field.
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Affiliation(s)
- Victoria L Castro
- Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX, 79968
| | - Anita M Quintana
- Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX, 79968
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24
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Li F, Bahnson EM, Wilder J, Siletzky R, Hagaman J, Nickekeit V, Hiller S, Ayesha A, Feng L, Levine JS, Takahashi N, Maeda-Smithies N. Oral high dose vitamin B12 decreases renal superoxide and post-ischemia/reperfusion injury in mice. Redox Biol 2020; 32:101504. [PMID: 32182573 PMCID: PMC7078436 DOI: 10.1016/j.redox.2020.101504] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 02/27/2020] [Accepted: 03/09/2020] [Indexed: 01/25/2023] Open
Abstract
Renal ischemia/reperfusion injury (IRI) is a leading cause of acute kidney injury (AKI), a potentially fatal syndrome characterized by a rapid decline in kidney function. Excess production of superoxide contributes to the injury. We hypothesized that oral administration of a high dose of vitamin B12 (B12 - cyanocobalamin), which possesses a superoxide scavenging function, would protect kidneys against IRI and provide a safe means of treatment. Following unilateral renal IR surgery, C57BL/6J wild type (WT) mice were administered B12 via drinking water at a dose of 50 mg/L. After 5 days of the treatment, plasma B12 levels increased by 1.2-1.5x, and kidney B12 levels increased by 7-8x. IRI mice treated with B12 showed near normal renal function and morphology. Further, IRI-induced changes in RNA and protein markers of inflammation, fibrosis, apoptosis, and DNA damage response (DDR) were significantly attenuated by at least 50% compared to those in untreated mice. Moreover, the presence of B12 at 0.3 μM in the culture medium of mouse proximal tubular cells subjected to 3 hr of hypoxia followed by 1 hr of reperfusion in vitro showed similar protective effects, including increased cell viability and decreased reactive oxygen species (ROS) level. We conclude that a high dose of B12 protects against perfusion injury both in vivo and in vitro without observable adverse effects in mice and suggest that B12 merits evaluation as a treatment for I/R-mediated AKI in humans.
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Affiliation(s)
- Feng Li
- Dept of Pathology and Laboratory Medicine, The University of North Carolina, Chapel Hill, NC, 27599, USA.
| | - Edward M Bahnson
- Department of Surgery, The University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Jennifer Wilder
- Dept of Pathology and Laboratory Medicine, The University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Robin Siletzky
- Department of Surgery, The University of North Carolina, Chapel Hill, NC, 27599, USA
| | - John Hagaman
- Dept of Pathology and Laboratory Medicine, The University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Volker Nickekeit
- Dept of Pathology and Laboratory Medicine, The University of North Carolina, Chapel Hill, NC, 27599, USA; Division of Nephropathy, School of Medicine, The University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Sylvia Hiller
- Dept of Pathology and Laboratory Medicine, The University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Azraa Ayesha
- Dept of Pathology and Laboratory Medicine, The University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Lanfei Feng
- Section of Nephrology, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, IL, 60612, USA
| | - Jerrold S Levine
- Section of Nephrology, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, IL, 60612, USA
| | - Nobuyuki Takahashi
- Dept of Pathology and Laboratory Medicine, The University of North Carolina, Chapel Hill, NC, 27599, USA; Division of Clinical Pharmacology and Therapeutics, Tohoku University Graduate School, Sendai, Japan
| | - Nobuyo Maeda-Smithies
- Dept of Pathology and Laboratory Medicine, The University of North Carolina, Chapel Hill, NC, 27599, USA
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25
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Dereven'kov IA, Hannibal L, Makarov SV, Molodtsov PA. Catalytic effect of riboflavin on electron transfer from NADH to aquacobalamin. J Biol Inorg Chem 2019; 25:125-133. [PMID: 31773269 DOI: 10.1007/s00775-019-01745-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 11/21/2019] [Indexed: 11/26/2022]
Abstract
Reduction of cobalamin by non-dedicated cellular reductases has been reported in earlier work, however, the sources of reducing power and the mechanisms are unknown. This study reports results of kinetic and mechanistic investigation of the reaction between aquacobalamin, H2OCbl, and reduced β-nicotinamide adenine dinucleotide, NADH. This interaction leads to the formation of one-electron reduced cobalamin, cob(II)alamin, and proceeds via water substitution on aquacobalamin by NADH and further decomposition of NADH-Co(III) complex to cob(II)alamin and NADH·+. Riboflavin catalyzes the reduction of aquacobalamin by NADH both in free form and with aquacobalamin bound to the cobalamin processing enzyme CblC. The rate-determining step of this catalytic reaction is the interaction between riboflavin and NADH to produce a charge transfer complex that reacts with aquacobalamin. Aquacobalamin quenches the fluorescence of NADH and riboflavin predominantly via a static mechanism.
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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, 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
- Department of Food Chemistry, Ivanovo State University of Chemistry and Technology, Sheremetevskiy Str. 7, 153000, Ivanovo, Russian Federation
| | - Pavel A Molodtsov
- Department of Food Chemistry, Ivanovo State University of Chemistry and Technology, Sheremetevskiy Str. 7, 153000, Ivanovo, Russian Federation
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26
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Froese DS, Fowler B, Baumgartner MR. Vitamin B 12 , folate, and the methionine remethylation cycle-biochemistry, pathways, and regulation. J Inherit Metab Dis 2019; 42:673-685. [PMID: 30693532 DOI: 10.1002/jimd.12009] [Citation(s) in RCA: 198] [Impact Index Per Article: 39.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 09/27/2018] [Accepted: 10/19/2018] [Indexed: 12/16/2022]
Abstract
Vitamin B12 (cobalamin, Cbl) is a nutrient essential to human health. Due to its complex structure and dual cofactor forms, Cbl undergoes a complicated series of absorptive and processing steps before serving as cofactor for the enzymes methylmalonyl-CoA mutase and methionine synthase. Methylmalonyl-CoA mutase is required for the catabolism of certain (branched-chain) amino acids into an anaplerotic substrate in the mitochondrion, and dysfunction of the enzyme itself or in production of its cofactor adenosyl-Cbl result in an inability to successfully undergo protein catabolism with concomitant mitochondrial energy disruption. Methionine synthase catalyzes the methyl-Cbl dependent (re)methylation of homocysteine to methionine within the methionine cycle; a reaction required to produce this essential amino acid and generate S-adenosylmethionine, the most important cellular methyl-donor. Disruption of methionine synthase has wide-ranging implications for all methylation-dependent reactions, including epigenetic modification, but also for the intracellular folate pathway, since methionine synthase uses 5-methyltetrahydrofolate as a one-carbon donor. Folate-bound one-carbon units are also required for deoxythymidine monophosphate and de novo purine synthesis; therefore, the flow of single carbon units to each of these pathways must be regulated based on cellular needs. This review provides an overview on Cbl metabolism with a brief description of absorption and intracellular metabolic pathways. It also provides a description of folate-mediated one-carbon metabolism and its intersection with Cbl at the methionine cycle. Finally, a summary of recent advances in understanding of how both pathways are regulated is presented.
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Affiliation(s)
- D Sean Froese
- Division of Metabolism and Children's Research Center, University Children's Hospital, Zurich, Switzerland
| | - Brian Fowler
- Division of Metabolism and Children's Research Center, University Children's Hospital, Zurich, Switzerland
| | - Matthias R Baumgartner
- Division of Metabolism and Children's Research Center, University Children's Hospital, Zurich, Switzerland
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27
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Lemoine M, Grangé S, Guerrot D. [Kidney disease in cobalamin C deficiency]. Nephrol Ther 2019; 15:201-214. [PMID: 31130431 DOI: 10.1016/j.nephro.2019.03.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 03/06/2019] [Indexed: 12/23/2022]
Abstract
Cobalamin C deficiency (cblC) is the most common inborn error of vitamin B12 metabolism. This autosomal recessive disease is due to mutations in MMACHC gene, encoding a cyanocobalamin decyanase. It leads to hyperhomocysteinemia associated with hypomethioninemia and methylmalonic aciduria. Two distinct phenotypes have been described : early-onset forms occur before the age of one year and are characterized by a severe multisystem disease associating failure to thrive to neurological and ophthalmological manifestations. They are opposed to late-onset forms, less severe and heterogeneous. CblC deficiency-associated kidney lesions remain poorly defined. Thirty-eight cases have been described. Age at initial presentation varied from a few days to 28 years. Most of the patients presented renal thrombotic microangiopathy (TMA) associated with acute renal failure, and 21 patients presented typical lesions of renal thrombotic microangiopathy on kidney biopsy. Prognosis was poor, leading to death in the absence of treatment, and related to the severity of renal lesions in the early-onset forms. Late-onset disease had better prognosis and most of patients were weaned off dialysis after treatment initiation. We suggest that all the patients with renal TMA be screened for cobalamin metabolism disorder, regardless of age and even in the absence of neurological symptoms, to rapidly initiate the appropriate treatment.
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Affiliation(s)
- Mathilde Lemoine
- Service de néphrologie, dialyse et transplantation, CHU de Rouen, 1, rue de Germont, 76031 Rouen, France.
| | - Steven Grangé
- Service de réanimation médicale, CHU de Rouen, 1, rue de Germont, 76031 Rouen, France
| | - Dominique Guerrot
- Service de néphrologie, dialyse et transplantation, CHU de Rouen, 1, rue de Germont, 76031 Rouen, France; Inserm U1096, UFR médecine pharmacie, 22, boulevard Gambetta, 76183 Rouen, France
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28
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Kozyraki R, Cases O. Cubilin, the Intrinsic Factor-Vitamin B12 Receptor in Development and Disease. Curr Med Chem 2018; 27:3123-3150. [PMID: 30295181 DOI: 10.2174/0929867325666181008143945] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 08/11/2018] [Accepted: 08/21/2018] [Indexed: 12/29/2022]
Abstract
Gp280/Intrinsic factor-vitamin B12 receptor/Cubilin (CUBN) is a large endocytic receptor serving multiple functions in vitamin B12 homeostasis, renal reabsorption of protein or toxic substances including albumin, vitamin D-binding protein or cadmium. Cubilin is a peripheral membrane protein consisting of 8 Epidermal Growth Factor (EGF)-like repeats and 27 CUB (defined as Complement C1r/C1s, Uegf, BMP1) domains. This structurally unique protein interacts with at least two molecular partners, Amnionless (AMN) and Lrp2/Megalin. AMN is involved in appropriate plasma membrane transport of Cubilin whereas Lrp2 is essential for efficient internalization of Cubilin and its ligands. Observations gleaned from animal models with Cubn deficiency or human diseases demonstrate the importance of this protein. In this review addressed to basic research and medical scientists, we summarize currently available data on Cubilin and its implication in renal and intestinal biology. We also discuss the role of Cubilin as a modulator of Fgf8 signaling during embryonic development and propose that the Cubilin-Fgf8 interaction may be relevant in human pathology, including in cancer progression, heart or neural tube defects. We finally provide experimental elements suggesting that some aspects of Cubilin physiology might be relevant in drug design.
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Affiliation(s)
- Renata Kozyraki
- INSERM UMRS 1138, Centre de Recherche des Cordeliers, Paris-Diderot University, Paris, France
| | - Olivier Cases
- INSERM UMRS 1138, Centre de Recherche des Cordeliers, Paris-Diderot University, Paris, France
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Campanello GC, Ruetz M, Dodge GJ, Gouda H, Gupta A, Twahir UT, Killian MM, Watkins D, Rosenblatt DS, Brunold TC, Warncke K, Smith JL, Banerjee R. Sacrificial Cobalt-Carbon Bond Homolysis in Coenzyme B 12 as a Cofactor Conservation Strategy. J Am Chem Soc 2018; 140:13205-13208. [PMID: 30282455 DOI: 10.1021/jacs.8b08659] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A sophisticated intracellular trafficking pathway in humans is used to tailor vitamin B12 into its active cofactor forms, and to deliver it to two known B12-dependent enzymes. Herein, we report an unexpected strategy for cellular retention of B12, an essential and reactive cofactor. If methylmalonyl-CoA mutase is unavailable to accept the coenzyme B12 product of adenosyltransferase, the latter catalyzes homolytic scission of the cobalt-carbon bond in an unconventional reversal of the nucleophilic displacement reaction that was used to make it. The resulting homolysis product binds more tightly to adenosyltransferase than does coenzyme B12, facilitating cofactor retention. We have trapped, and characterized spectroscopically, an intermediate in which the cobalt-carbon bond is weakened prior to being broken. The physiological relevance of this sacrificial catalytic activity for cofactor retention is supported by the significantly lower coenzyme B12 concentration in patients with dysfunctional methylmalonyl-CoA mutase but normal adenosyltransferase activity.
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Affiliation(s)
- Gregory C Campanello
- Department of Biological Chemistry , University of Michigan , Ann Arbor , Michigan 48109-0600 , United States
| | - Markus Ruetz
- Department of Biological Chemistry , University of Michigan , Ann Arbor , Michigan 48109-0600 , United States
| | - Greg J Dodge
- Department of Biological Chemistry , University of Michigan , Ann Arbor , Michigan 48109-0600 , United States.,Life Sciences Institute, University of Michigan , Ann Arbor , Michigan 48109-0600 , United States
| | - Harsha Gouda
- Department of Biological Chemistry , University of Michigan , Ann Arbor , Michigan 48109-0600 , United States.,Indian Institute of Science Education and Research , Pune 411008 , India
| | - Aditi Gupta
- Department of Biological Chemistry , University of Michigan , Ann Arbor , Michigan 48109-0600 , United States
| | - Umar T Twahir
- Department of Physics , Emory University , Atlanta , Georgia 30322-2430 , United States
| | - Michelle M Killian
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - David Watkins
- Department of Human Genetics , McGill University , Montreal , Quebec H3A 1B1 , Canada
| | - David S Rosenblatt
- Department of Human Genetics , McGill University , Montreal , Quebec H3A 1B1 , Canada
| | - Thomas C Brunold
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Kurt Warncke
- Department of Physics , Emory University , Atlanta , Georgia 30322-2430 , United States
| | - Janet L Smith
- Department of Biological Chemistry , University of Michigan , Ann Arbor , Michigan 48109-0600 , United States.,Life Sciences Institute, University of Michigan , Ann Arbor , Michigan 48109-0600 , United States
| | - Ruma Banerjee
- Department of Biological Chemistry , University of Michigan , Ann Arbor , Michigan 48109-0600 , United States
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30
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Hannibal L, Bolisetty K, Axhemi A, DiBello PM, Quadros EV, Fedosov S, Jacobsen DW. Transcellular transport of cobalamin in aortic endothelial cells. FASEB J 2018; 32:5506-5519. [PMID: 29741927 DOI: 10.1096/fj.201701141rr] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Cobalamin [Cbl (or B12)] deficiency causes megaloblastic anemia and a variety of neuropathies. However, homeostatic mechanisms of cyanocobalamin (CNCbl) and other Cbls by vascular endothelial cells are poorly understood. Herein, we describe our investigation into whether cultured bovine aortic endothelial cells (BAECs) perform transcytosis of B12, namely, the complex formed between serum transcobalamin and B12, designated as holo-transcobalamin (holo-TC). We show that cultured BAECs endocytose [57Co]-CNCbl-TC (source material) via the CD320 receptor. The bound Cbl is transported across the cell both via exocytosis in its free form, [57Co]-CNCbl, and via transcytosis as [57Co]-CNCbl-TC. Transcellular mobilization of Cbl occurred in a bidirectional manner. A portion of the endocytosed [57Co]-CNCbl was enzymatically processed by methylmalonic aciduria combined with homocystinuria type C (cblC) with subsequent formation of hydroxocobalamin, methylcobalamin, and adenosylcobalamin, which were also transported across the cell in a bidirectional manner. This demonstrates that transport mechanisms for Cbl in vascular endothelial cells do not discriminate between various β-axial ligands of the vitamin. Competition studies with apoprotein- and holo-TC and holo-intrinsic factor showed that only holo-TC was effective at inhibiting transcellular transport of Cbl. Incubation of BAECs with a blocking antibody against the extracellular domain of the CD320 receptor inhibited uptake and transcytosis by ∼40%. This study reveals that endothelial cells recycle uncommitted intracellular Cbl for downstream usage by other cell types and suggests that the endothelium is self-sufficient for the specific acquisition and subsequent distribution of circulating B12 via the CD320 receptor. We posit that the endothelial lining of the vasculature is an essential component for the maintenance of serum-tissue homeostasis of B12.-Hannibal, L., Bolisetty, K., Axhemi, A., DiBello, P. M., Quadros, E. V., Fedosov, S., Jacobsen, D. W. Transcellular transport of cobalamin in aortic endothelial cells.
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Affiliation(s)
- Luciana Hannibal
- Laboratory of Clinical Biochemistry and Metabolism, Department for Pediatrics, Medical Center, University of Freiburg, Freiburg, Germany.,Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Keerthana Bolisetty
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Armend Axhemi
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Patricia M DiBello
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Edward V Quadros
- Department of Medicine, State University of New York (SUNY) Downstate Medical Center, Brooklyn, New York, USA; and
| | - Sergey Fedosov
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Donald W Jacobsen
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
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31
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Dereven'kov IA, Hannibal L, Makarov SV, Makarova AS, Molodtsov PA, Koifman OI. Characterization of the complex between native and reduced bovine serum albumin with aquacobalamin and evidence of dual tetrapyrrole binding. J Biol Inorg Chem 2018; 23:725-738. [PMID: 29721769 DOI: 10.1007/s00775-018-1562-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Accepted: 04/25/2018] [Indexed: 11/30/2022]
Abstract
Serum albumin binds to a variety of endogenous ligands and drugs. Human serum albumin (HSA) binds to heme via hydrophobic interactions and axial coordination of the iron center by protein residue Tyr161. Human serum albumin binds to another tetrapyrrole, cobalamin (Cbl), but the structural and functional properties of this complex are poorly understood. Herein, we investigate the reaction between aquacobalamin (H2OCbl) and bovine serum albumin (BSA, the bovine counterpart of HSA) using Ultraviolet-Visible and fluorescent spectroscopy, and electron paramagnetic resonance. The reaction between H2OCbl and BSA led to the formation of a BSA-Cbl(III) complex consistent with N-axial ligation (amino). Prior to the formation of this complex, the reactants participate in an additional binding event that has been examined by fluorescence spectroscopy. Binding of BSA to Cbl(III) reduced complex formation between the bound cobalamin and free cyanide to form cyanocobalamin (CNCbl), suggesting that the β-axial position of the cobalamin may be occupied by an amino acid residue from the protein. Reaction of BSA containing reduced disulfide bonds with H2OCbl produces cob(II)alamin and disulfide with intermediate formation of thiolate Cbl(III)-BSA complex and its decomposition. Finally, in vitro studies showed that cobalamin binds to BSA only in the presence of an excess of protein, which is in contrast to heme binding to BSA that involves a 1:1 stoichiometry. In vitro formation of BSA-Cbl(III) complex does not preclude subsequent heme binding, which occurs without displacement of H2OCbl bound to BSA. These data suggest that the two tetrapyrroles interact with BSA in different binding pockets.
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Affiliation(s)
- Ilia A Dereven'kov
- Institute of Macroheterocyclic Compounds, Ivanovo State University of Chemistry and Technology, Sheremetevskiy Str. 7, Ivanovo, 153000, Russian Federation.
| | - Luciana Hannibal
- Laboratory of Clinical Biochemistry and Metabolism, Department for Pediatrics, Medical Center, University of Freiburg, Mathildenstr. 1, 79106, Freiburg, Germany
| | - Sergei V Makarov
- Institute of Macroheterocyclic Compounds, Ivanovo State University of Chemistry and Technology, Sheremetevskiy Str. 7, Ivanovo, 153000, Russian Federation
| | - Anna S Makarova
- G. A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences, Academicheskaya Str 1, Ivanovo, 153045, Russian Federation
| | - Pavel A Molodtsov
- Institute of Macroheterocyclic Compounds, Ivanovo State University of Chemistry and Technology, Sheremetevskiy Str. 7, Ivanovo, 153000, Russian Federation
| | - Oskar I Koifman
- Institute of Macroheterocyclic Compounds, Ivanovo State University of Chemistry and Technology, Sheremetevskiy Str. 7, Ivanovo, 153000, Russian Federation
- G. A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences, Academicheskaya Str 1, Ivanovo, 153045, Russian Federation
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32
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Abstract
The biosynthesis of B12, involving up to 30 different enzyme-mediated steps, only occurs in bacteria. Thus, most eukaryotes require an external source of B12, and yet the vitamin appears to have only two functions in eukaryotes: as a cofactor for the enzymes methionine synthase and methylmalonylCoA mutase. These two functions are crucial for normal health in humans, and in particular, the formation of methionine is essential for providing methyl groups for over 100 methylation processes. Interference with the methionine synthase reaction not only depletes the body of methyl groups but also leads to the accumulation of homocysteine, a risk factor for many diseases. The syndrome pernicious anemia, characterized by lack of intrinsic factor, leads to a severe, sometimes fatal form of B12 deficiency. However, there is no sharp cutoff for B12 deficiency; rather, there is a continuous inverse relationship between serum B12 and a variety of undesirable outcomes, including neural tube defects, stroke, and dementia. The brain is particularly vulnerable; in children, inadequate B12 stunts brain and intellectual development. Suboptimal B12 status (serum B12<300pmol/L) is very common, occurring in 30%-60% of the population, in particular in pregnant women and in less-developed countries. Thus, many tens of millions of people in the world may suffer harm from having a poor B12 status. Public health steps are urgently needed to correct this inadequacy.
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Affiliation(s)
- A David Smith
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom.
| | - Martin J Warren
- School of Biosciences, University of Kent, Canterbury, Kent, United Kingdom
| | - Helga Refsum
- Department of Nutrition, University of Oslo, Oslo, Norway
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D'Ulivo L, Yang L, Ding J, Pagliano E, Leek DM, Thibeault MP, Mester Z. Determination of cyanocobalamin by isotope dilution LC-MS/MS. Anal Chim Acta 2017; 990:103-109. [DOI: 10.1016/j.aca.2017.07.065] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 07/28/2017] [Accepted: 07/29/2017] [Indexed: 10/19/2022]
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Fettelschoss V, Burda P, Sagné C, Coelho D, De Laet C, Lutz S, Suormala T, Fowler B, Pietrancosta N, Gasnier B, Bornhauser B, Froese DS, Baumgartner MR. Clinical or ATPase domain mutations in ABCD4 disrupt the interaction between the vitamin B 12-trafficking proteins ABCD4 and LMBD1. J Biol Chem 2017; 292:11980-11991. [PMID: 28572511 DOI: 10.1074/jbc.m117.784819] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 05/24/2017] [Indexed: 01/19/2023] Open
Abstract
Vitamin B12 (cobalamin (Cbl)), in the cofactor forms methyl-Cbl and adenosyl-Cbl, is required for the function of the essential enzymes methionine synthase and methylmalonyl-CoA mutase, respectively. Cbl enters mammalian cells by receptor-mediated endocytosis of protein-bound Cbl followed by lysosomal export of free Cbl to the cytosol and further processing to these cofactor forms. The integral membrane proteins LMBD1 and ABCD4 are required for lysosomal release of Cbl, and mutations in the genes LMBRD1 and ABCD4 result in the cobalamin metabolism disorders cblF and cblJ. We report a new (fifth) patient with the cblJ disorder who presented at 7 days of age with poor feeding, hypotonia, methylmalonic aciduria, and elevated plasma homocysteine and harbored the mutations c.1667_1668delAG [p.Glu556Glyfs*27] and c.1295G>A [p.Arg432Gln] in the ABCD4 gene. Cbl cofactor forms are decreased in fibroblasts from this patient but could be rescued by overexpression of either ABCD4 or, unexpectedly, LMBD1. Using a sensitive live-cell FRET assay, we demonstrated selective interaction between ABCD4 and LMBD1 and decreased interaction when ABCD4 harbored the patient mutations p.Arg432Gln or p.Asn141Lys or when artificial mutations disrupted the ATPase domain. Finally, we showed that ABCD4 lysosomal targeting depends on co-expression of, and interaction with, LMBD1. These data broaden the patient and mutation spectrum of cblJ deficiency, establish a sensitive live-cell assay to detect the LMBD1-ABCD4 interaction, and confirm the importance of this interaction for proper intracellular targeting of ABCD4 and cobalamin cofactor synthesis.
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Affiliation(s)
- Victoria Fettelschoss
- Division of Metabolism and Children's Research Center, University Children's Hospital, CH-8032 Zurich, Switzerland
| | - Patricie Burda
- Division of Metabolism and Children's Research Center, University Children's Hospital, CH-8032 Zurich, Switzerland
| | - Corinne Sagné
- Neurophotonics Laboratory UMR 8250, Paris Descartes University, CNRS, Sorbonne Paris Cité, F-75006 Paris, France
| | - David Coelho
- UMR-S UL-INSERM U954 Nutrition-Genetics-Environmental Risk Exposure and Reference Centre of Inborn Metabolism Diseases, Medical Faculty of Nancy University and University Hospital Centre, Nancy, France
| | - Corinne De Laet
- Nutrition and Metabolism Unit, Queen Fabiola Children's University Hospital, Free University of Brussels (ULB), 1020 Brussels, Belgium
| | - Seraina Lutz
- Division of Metabolism and Children's Research Center, University Children's Hospital, CH-8032 Zurich, Switzerland
| | - Terttu Suormala
- Division of Metabolism and Children's Research Center, University Children's Hospital, CH-8032 Zurich, Switzerland
| | - Brian Fowler
- Division of Metabolism and Children's Research Center, University Children's Hospital, CH-8032 Zurich, Switzerland
| | - Nicolas Pietrancosta
- CBMIT team, UMR 8601, Paris Descartes University, CNRS, Sorbonne Paris Cité, F-75006 Paris, France
| | - Bruno Gasnier
- Neurophotonics Laboratory UMR 8250, Paris Descartes University, CNRS, Sorbonne Paris Cité, F-75006 Paris, France
| | - Beat Bornhauser
- Department of Oncology, Children's Research Center, University Children's Hospital, CH-8032 Zurich, Switzerland
| | - D Sean Froese
- Division of Metabolism and Children's Research Center, University Children's Hospital, CH-8032 Zurich, Switzerland; Rare Disease Initiative Zurich (radiz), Clinical Research Priority Program for Rare Diseases, University of Zurich, CH-8006 Zurich, Switzerland.
| | - Matthias R Baumgartner
- Division of Metabolism and Children's Research Center, University Children's Hospital, CH-8032 Zurich, Switzerland; Rare Disease Initiative Zurich (radiz), Clinical Research Priority Program for Rare Diseases, University of Zurich, CH-8006 Zurich, Switzerland; Zurich Center for Integrative Human Physiology, University of Zurich, CH-8006 Zurich, Switzerland.
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Dereven'kov IA, Hannibal L, Dürr M, Salnikov DS, Bui Thi TT, Makarov SV, Koifman OI, Ivanović-Burmazović I. Redox turnover of organometallic B 12 cofactors recycles vitamin C: Sulfur assisted reduction of dehydroascorbic acid by cob(II)alamin. J Organomet Chem 2017. [DOI: 10.1016/j.jorganchem.2017.01.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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36
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Ruetz M, Shanmuganathan A, Gherasim C, Karasik A, Salchner R, Kieninger C, Wurst K, Banerjee R, Koutmos M, Kräutler B. Inhibierung des humanen B12-verarbeitenden Enzyms CblC durch Antivitamine B12- Kristallstruktur des inaktiven ternären Komplexes mit dem Kosubstrat Glutathion. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201701583] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Markus Ruetz
- Institut für Organische Chemie und Zentrum für Molekulare, Biowissenschaften; Universität Innsbruck; 6020 Innsbruck Österreich
- University of Michigan Medical School; Ann Arbor MI 48109-0600 USA
| | | | - Carmen Gherasim
- University of Michigan Medical School; Ann Arbor MI 48109-0600 USA
- Department of Pathology; University of Utah School of Medicine; Salt Lake City UT USA
| | - Agnes Karasik
- Department of Biochemistry; Uniformed Services University of the Health Sciences; Bethesda MD 28104 USA
| | - Robert Salchner
- Institut für Organische Chemie und Zentrum für Molekulare, Biowissenschaften; Universität Innsbruck; 6020 Innsbruck Österreich
- Watercryst GmbH & Co; Kematen Österreich
| | - Christoph Kieninger
- Institut für Organische Chemie und Zentrum für Molekulare, Biowissenschaften; Universität Innsbruck; 6020 Innsbruck Österreich
| | - Klaus Wurst
- Institut für Allgemeine, Anorganische Chemie und Theoretische Chemie; Universität Innsbruck; Österreich
| | - Ruma Banerjee
- University of Michigan Medical School; Ann Arbor MI 48109-0600 USA
| | - Markos Koutmos
- Department of Biochemistry; Uniformed Services University of the Health Sciences; Bethesda MD 28104 USA
| | - Bernhard Kräutler
- Institut für Organische Chemie und Zentrum für Molekulare, Biowissenschaften; Universität Innsbruck; 6020 Innsbruck Österreich
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37
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Ruetz M, Shanmuganathan A, Gherasim C, Karasik A, Salchner R, Kieninger C, Wurst K, Banerjee R, Koutmos M, Kräutler B. Antivitamin B 12 Inhibition of the Human B 12 -Processing Enzyme CblC: Crystal Structure of an Inactive Ternary Complex with Glutathione as the Cosubstrate. Angew Chem Int Ed Engl 2017; 56:7387-7392. [PMID: 28544088 DOI: 10.1002/anie.201701583] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Indexed: 02/06/2023]
Abstract
B12 antivitamins are important and robust tools for investigating the biological roles of vitamin B12 . Here, the potential antivitamin B12 2,4-difluorophenylethynylcobalamin (F2PhEtyCbl) was prepared, and its 3D structure was studied in solution and in the crystal. Chemically inert F2PhEtyCbl resisted thermolysis of its Co-C bond at 100 °C, was stable in bright daylight, and also remained intact upon prolonged storage in aqueous solution at room temperature. It binds to the human B12 -processing enzyme CblC with high affinity (KD =130 nm) in the presence of the cosubstrate glutathione (GSH). F2PhEtyCbl withstood tailoring by CblC, and it also stabilized the ternary complex with GSH. The crystal structure of this inactivated assembly provides first insight into the binding interactions between an antivitamin B12 and CblC, as well as into the organization of GSH and a base-off cobalamin in the active site of this enzyme.
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Affiliation(s)
- Markus Ruetz
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, 6020, Innsbruck, Austria.,University of Michigan Medical School, Ann Arbor, USA
| | | | - Carmen Gherasim
- University of Michigan Medical School, Ann Arbor, USA.,Current address: Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Agnes Karasik
- Department of Biochemistry, Uniformed Services University of the Health Sciences, Bethesda, USA
| | - Robert Salchner
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, 6020, Innsbruck, Austria.,Current address: Watercryst GmbH & Co, Kematen, Austria
| | - Christoph Kieninger
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, 6020, Innsbruck, Austria
| | - Klaus Wurst
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Austria
| | - Ruma Banerjee
- University of Michigan Medical School, Ann Arbor, USA
| | - Markos Koutmos
- Department of Biochemistry, Uniformed Services University of the Health Sciences, Bethesda, USA
| | - Bernhard Kräutler
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, 6020, Innsbruck, Austria
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Possible Involvement of Hydrosulfide in B 12-Dependent Methyl Group Transfer. Molecules 2017; 22:molecules22040582. [PMID: 28379205 PMCID: PMC6154648 DOI: 10.3390/molecules22040582] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 03/22/2017] [Accepted: 03/30/2017] [Indexed: 11/29/2022] Open
Abstract
Evidence from several fields of investigation lead to the hypothesis that the sulfur atom is involved in vitamin B12-dependent methyl group transfer. To compile the evidence, it is necessary to briefly review the following fields: methylation, the new field of sulfane sulfur/hydrogen sulfide (S°/H2S), hydrosulfide derivatives of cobalamins, autoxidation of hydrosulfide radical, radical S-adenosylmethionine methyl transfer (RSMT), and methionine synthase (MS). Then, new reaction mechanisms for B12-dependent methyl group transfer are proposed; the mechanisms are facile and overcome difficulties that existed in previously-accepted mechanisms. Finally, the theory is applied to the effect of S°/H2S in nerve tissue involving the “hypomethylation theory” that was proposed 50 years ago to explain the neuropathology resulting from deficiency of vitamin B12 or folic acid. The conclusions are consistent with emerging evidence that sulfane sulfur/hydrogen sulfide may be beneficial in treating Alzheimer’s disease.
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Hannibal L, Siebert M, Basgalupp S, Vario F, Spiekerkoetter U, Blom HJ. Hampered Vitamin B12 Metabolism in Gaucher Disease? JOURNAL OF INBORN ERRORS OF METABOLISM AND SCREENING 2017. [DOI: 10.1177/2326409817692359] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
- Luciana Hannibal
- Laboratory of Clinical Biochemistry and Metabolism, Department of Pediatrics, Medical Center, University of Freiburg, Freiburg, Germany
| | - Marina Siebert
- Hospital de Clínicas de Porto Alegre—HCPA, Medical Genetics Service, Porto Alegre, Rio Grande do Sul, Brazil
| | - Suélen Basgalupp
- Hospital de Clínicas de Porto Alegre—HCPA, Medical Genetics Service, Porto Alegre, Rio Grande do Sul, Brazil
| | - Filippo Vario
- Hospital de Clínicas de Porto Alegre—HCPA, Medical Genetics Service, Porto Alegre, Rio Grande do Sul, Brazil
| | - Ute Spiekerkoetter
- Laboratory of Clinical Biochemistry and Metabolism, Department of Pediatrics, Medical Center, University of Freiburg, Freiburg, Germany
| | - Henk J. Blom
- Laboratory of Clinical Biochemistry and Metabolism, Department of Pediatrics, Medical Center, University of Freiburg, Freiburg, Germany
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Huemer M, Diodato D, Schwahn B, Schiff M, Bandeira A, Benoist JF, Burlina A, Cerone R, Couce ML, Garcia-Cazorla A, la Marca G, Pasquini E, Vilarinho L, Weisfeld-Adams JD, Kožich V, Blom H, Baumgartner MR, Dionisi-Vici C. Guidelines for diagnosis and management of the cobalamin-related remethylation disorders cblC, cblD, cblE, cblF, cblG, cblJ and MTHFR deficiency. J Inherit Metab Dis 2017; 40:21-48. [PMID: 27905001 PMCID: PMC5203859 DOI: 10.1007/s10545-016-9991-4] [Citation(s) in RCA: 180] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 09/28/2016] [Accepted: 10/04/2016] [Indexed: 12/22/2022]
Abstract
BACKGROUND Remethylation defects are rare inherited disorders in which impaired remethylation of homocysteine to methionine leads to accumulation of homocysteine and perturbation of numerous methylation reactions. OBJECTIVE To summarise clinical and biochemical characteristics of these severe disorders and to provide guidelines on diagnosis and management. DATA SOURCES Review, evaluation and discussion of the medical literature (Medline, Cochrane databases) by a panel of experts on these rare diseases following the GRADE approach. KEY RECOMMENDATIONS We strongly recommend measuring plasma total homocysteine in any patient presenting with the combination of neurological and/or visual and/or haematological symptoms, subacute spinal cord degeneration, atypical haemolytic uraemic syndrome or unexplained vascular thrombosis. We strongly recommend to initiate treatment with parenteral hydroxocobalamin without delay in any suspected remethylation disorder; it significantly improves survival and incidence of severe complications. We strongly recommend betaine treatment in individuals with MTHFR deficiency; it improves the outcome and prevents disease when given early.
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Affiliation(s)
- Martina Huemer
- Division of Metabolism and Children's Research Center, University Childrens' Hospital Zürich, Zurich, Switzerland
- radiz - Rare Disease Initiative Zürich, Clinical Research Priority Program, University of Zürich, Zurich, Switzerland
- Department of Paediatrics, Landeskrankenhaus Bregenz, Bregenz, Austria
| | - Daria Diodato
- Division of Metabolism, Bambino Gesù Children's Research Hospital, Rome, Italy
| | - Bernd Schwahn
- Willink Biochemical Genetics Unit, Saint Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, M13 9WL, UK
| | - Manuel Schiff
- Reference Center for Inborn Errors of Metabolism, Robert Debré University Hospital, APHP, Paris, France
- Inserm U1141, Robert Debré Hospital, Paris, France
- Université Paris-Diderot, Sorbonne Paris Cité, site Robert Debré, Paris, France
| | | | - Jean-Francois Benoist
- Reference Center for Inborn Errors of Metabolism, Robert Debré University Hospital, APHP, Paris, France
- Inserm U1141, Robert Debré Hospital, Paris, France
- Biochimie, faculté de pharmacie, Université Paris Sud, Paris, France
| | - Alberto Burlina
- Division of Inherited Metabolic Diseases, Department of Pediatrics, University Hospital Padova, Padova, Italy
| | - Roberto Cerone
- University Dept of Pediatrics, Giannina Gaslini Institute, Genoa, Italy
| | - Maria L Couce
- Congenital Metabolic Diseases Unit, Hospital Clínico Universitario de Santiago de Compostela, IDIS, CIBER, Compostela, Spain
| | - Angeles Garcia-Cazorla
- Department of Neurology, Neurometabolism Unit, and CIBERER (ISCIII), Hospital Sant Joan de Deu, Barcelona, Spain
| | - Giancarlo la Marca
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Firence, Italy
| | - Elisabetta Pasquini
- Metabolic and Newborn Screening Clinical Unit, Department of Neurosciences, A. Meyer Children's University Hospital, Florence, Italy
| | - Laura Vilarinho
- Newborn Screening, Metabolism & Genetics Unit, National Institute of Health, Porto, Portugal
| | - James D Weisfeld-Adams
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
- Inherited Metabolic Diseases Clinic, Childrens Hospital Colorado, Aurora, CO, USA
| | - Viktor Kožich
- Institute of Inherited Metabolic Disorders, Charles University-First Faculty of Medicine and General University Hospital, Prague, Czech Republic
| | - Henk Blom
- Laboratory of Clinical Biochemistry and Metabolism, Center for Pediatrics and Adolescent Medicine University Hospital, Freiburg, Freiburg, Germany
| | - Matthias R Baumgartner
- Division of Metabolism and Children's Research Center, University Childrens' Hospital Zürich, Zurich, Switzerland.
- radiz - Rare Disease Initiative Zürich, Clinical Research Priority Program, University of Zürich, Zurich, Switzerland.
| | - Carlo Dionisi-Vici
- Division of Metabolism, Bambino Gesù Children's Research Hospital, Rome, Italy.
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Rizzo G, Laganà AS, Rapisarda AMC, La Ferrera GMG, Buscema M, Rossetti P, Nigro A, Muscia V, Valenti G, Sapia F, Sarpietro G, Zigarelli M, Vitale SG. Vitamin B12 among Vegetarians: Status, Assessment and Supplementation. Nutrients 2016; 8:E767. [PMID: 27916823 PMCID: PMC5188422 DOI: 10.3390/nu8120767] [Citation(s) in RCA: 177] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Revised: 11/23/2016] [Accepted: 11/23/2016] [Indexed: 02/06/2023] Open
Abstract
Cobalamin is an essential molecule for humans. It acts as a cofactor in one-carbon transfers through methylation and molecular rearrangement. These functions take place in fatty acid, amino acid and nucleic acid metabolic pathways. The deficiency of vitamin B12 is clinically manifested in the blood and nervous system where the cobalamin plays a key role in cell replication and in fatty acid metabolism. Hypovitaminosis arises from inadequate absorption, from genetic defects that alter transport through the body, or from inadequate intake as a result of diet. With the growing adoption of vegetarian eating styles in Western countries, there is growing focus on whether diets that exclude animal foods are adequate. Since food availability in these countries is not a problem, and therefore plant foods are sufficiently adequate, the most delicate issue remains the contribution of cobalamin, which is poorly represented in plants. In this review, we will discuss the status of vitamin B12 among vegetarians, the diagnostic markers for the detection of cobalamin deficiency and appropriate sources for sufficient intake, through the description of the features and functions of vitamin B12 and its absorption mechanism.
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Affiliation(s)
| | - Antonio Simone Laganà
- Unit of Gynecology and Obstetrics, Department of Human Pathology in Adulthood and Childhood, "G. Barresi", University of Messina, Via Consolare Valeria 1, Messina 98125, Italy.
| | - Agnese Maria Chiara Rapisarda
- Department of General Surgery and Medical Surgical Specialties, University of Catania, Via S. Sofia 78, Catania 95124, Italy.
| | - Gioacchina Maria Grazia La Ferrera
- Department of Gastroenterology and Digestive Endoscopy Maddalena Raimondi San Cataldo, Via Forlanini 5, San Cataldo, Caltanissetta 93017, Italy.
| | - Massimo Buscema
- Unit of Diabetology and Endocrino-Metabolic Diseases, Hospital for Emergency Cannizzaro, Via Messina 829, Catania 95126, Italy.
| | - Paola Rossetti
- Unit of Diabetology and Endocrino-Metabolic Diseases, Hospital for Emergency Cannizzaro, Via Messina 829, Catania 95126, Italy.
| | - Angela Nigro
- Unit of Diabetology and Endocrino-Metabolic Diseases, Hospital for Emergency Cannizzaro, Via Messina 829, Catania 95126, Italy.
| | - Vincenzo Muscia
- Unit of Diabetology and Endocrino-Metabolic Diseases, Hospital for Emergency Cannizzaro, Via Messina 829, Catania 95126, Italy.
| | - Gaetano Valenti
- Department of General Surgery and Medical Surgical Specialties, University of Catania, Via S. Sofia 78, Catania 95124, Italy.
| | - Fabrizio Sapia
- Department of General Surgery and Medical Surgical Specialties, University of Catania, Via S. Sofia 78, Catania 95124, Italy.
| | - Giuseppe Sarpietro
- Department of General Surgery and Medical Surgical Specialties, University of Catania, Via S. Sofia 78, Catania 95124, Italy.
| | - Micol Zigarelli
- Department of General Surgery and Medical Surgical Specialties, University of Catania, Via S. Sofia 78, Catania 95124, Italy.
| | - Salvatore Giovanni Vitale
- Unit of Gynecology and Obstetrics, Department of Human Pathology in Adulthood and Childhood, "G. Barresi", University of Messina, Via Consolare Valeria 1, Messina 98125, Italy.
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Zhao H, Ruberu K, Li H, Garner B. Cell Type-Specific Modulation of Cobalamin Uptake by Bovine Serum. PLoS One 2016; 11:e0167044. [PMID: 27893837 PMCID: PMC5125665 DOI: 10.1371/journal.pone.0167044] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 11/07/2016] [Indexed: 12/04/2022] Open
Abstract
Tracking cellular 57Co-labelled cobalamin (57Co-Cbl) uptake is a well-established method for studying Cbl homeostasis. Previous studies established that bovine serum is not generally permissive for cellular Cbl uptake when used as a supplement in cell culture medium, whereas supplementation with human serum promotes cellular Cbl uptake. The underlying reasons for these differences are not fully defined. In the current study we address this question. We extend earlier observations by showing that fetal calf serum inhibits cellular 57Co-Cbl uptake by HT1080 cells (a fibrosarcoma-derived fibroblast cell line). Furthermore, we discovered that a simple heat-treatment protocol (95°C for 10 min) ameliorates this inhibitory activity for HT1080 cell 57Co-Cbl uptake. We provide evidence that the very high level of haptocorrin in bovine serum (as compared to human serum) is responsible for this inhibitory activity. We suggest that bovine haptocorrin competes with cell-derived transcobalamin for Cbl binding, and that cellular Cbl uptake may be minimised in the presence of large amounts of bovine haptocorrin that are present under routine in vitro cell culture conditions. In experiments conducted with AG01518 cells (a neonatal foreskin-derived fibroblast cell line), overall cellular 57Co-Cbl uptake was 86% lower than for HT1080 cells, cellular TC production was below levels detectable by western blotting, and heat treatment of fetal calf serum resulted in only a modest increase in cellular 57Co-Cbl uptake. We recommend a careful assessment of cell culture protocols should be conducted in order to determine the potential benefits that heat-treated bovine serum may provide for in vitro studies of mammalian cell lines.
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Affiliation(s)
- Hua Zhao
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- School of Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
| | - Kalani Ruberu
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- School of Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
| | - Hongyun Li
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- School of Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
| | - Brett Garner
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- School of Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
- * E-mail:
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Methylfolate Trap Promotes Bacterial Thymineless Death by Sulfa Drugs. PLoS Pathog 2016; 12:e1005949. [PMID: 27760199 PMCID: PMC5070874 DOI: 10.1371/journal.ppat.1005949] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 09/22/2016] [Indexed: 01/16/2023] Open
Abstract
The methylfolate trap, a metabolic blockage associated with anemia, neural tube defects, Alzheimer’s dementia, cardiovascular diseases, and cancer, was discovered in the 1960s, linking the metabolism of folate, vitamin B12, methionine and homocysteine. However, the existence or physiological significance of this phenomenon has been unknown in bacteria, which synthesize folate de novo. Here we identify the methylfolate trap as a novel determinant of the bacterial intrinsic death by sulfonamides, antibiotics that block de novo folate synthesis. Genetic mutagenesis, chemical complementation, and metabolomic profiling revealed trap-mediated metabolic imbalances, which induced thymineless death, a phenomenon in which rapidly growing cells succumb to thymine starvation. Restriction of B12 bioavailability, required for preventing trap formation, using an “antivitamin B12” molecule, sensitized intracellular bacteria to sulfonamides. Since boosting the bactericidal activity of sulfonamides through methylfolate trap induction can be achieved in Gram-negative bacteria and mycobacteria, it represents a novel strategy to render these pathogens more susceptible to existing sulfonamides. Sulfonamides were the first agents to successfully treat bacterial infections, but their use later declined due to the emergence of resistant organisms. Restoration of these drugs may be achieved through inactivation of molecular mechanisms responsible for resistance. A chemo-genomic screen first identified 50 chromosomal loci representing the whole-genome antifolate resistance determinants in Mycobacterium smegmatis. Interestingly, many determinants resembled components of the methylfolate trap, a metabolic blockage exclusively described in mammalian cells. Targeted mutagenesis, genetic and chemical complementation, followed by chemical analyses established the methylfolate trap as a novel mechanism of sulfonamide sensitivity, ubiquitously present in mycobacteria and Gram-negative bacterial pathogens. Furthermore, metabolomic analyses revealed trap-mediated interruptions in folate and related metabolic pathways. These metabolic imbalances induced thymineless death, which was reversible with exogenous thymine supplementation. Chemical restriction of vitamin B12, an important molecule required for prevention of the methylfolate trap, sensitized intracellular bacteria to sulfonamides. Thus, pharmaceutical promotion of the methylfolate trap represents a novel folate antagonistic strategy to render pathogenic bacteria more susceptible to available, clinically approved sulfonamides.
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Nogueira C, Marcão A, Rocha H, Sousa C, Fonseca H, Valongo C, Vilarinho L. Molecular picture of cobalamin C/D defects before and after newborn screening era. J Med Screen 2016; 24:6-11. [DOI: 10.1177/0969141316641149] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Objective Birth prevalence of Cobalamin (Cbl) C or D defects in Portugal is an estimated 1:85,000, one of the highest worldwide. We compared the genotype/phenotype of patients identified with CblC or CblD before and after the implementation of expanded newborn screening. Methods Twenty-five Portuguese CblC/D patients, 14 symptomatic and 11 identified through screening, were diagnosed using gas chromatography or tandem mass spectrometry. Molecular characterization was performed through the study of MMACHC and MMADHC genes. Results The most common MMACHC mutation, c.271dupA, was present in 100% of MMACHC alleles of all CblC screened patients, in contrast with the 61% identified before expanded newborn screening. All studied cases (except one, who presented a CblD deficiency) presented a CblC defect. More CblC late-onset patients were diagnosed before the introduction of newborn screening than in the post newborn screening era, probably because some early onset patients died without a definitive diagnosis. Conclusion The molecular data found in this cohort contribute to the improvement of screening and diagnosis of Cbl defects and would enable a confirmatory diagnosis of these patients, reducing the need for complex, costly, laborious, and time-consuming biochemical/enzymatic tests.
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Affiliation(s)
- C Nogueira
- Newborn Screening, Metabolism & Genetics Unit, Human Genetics Department, National Institute of Health Dr Ricardo Jorge, Porto, Portugal
| | - A Marcão
- Newborn Screening, Metabolism & Genetics Unit, Human Genetics Department, National Institute of Health Dr Ricardo Jorge, Porto, Portugal
| | - H Rocha
- Newborn Screening, Metabolism & Genetics Unit, Human Genetics Department, National Institute of Health Dr Ricardo Jorge, Porto, Portugal
| | - C Sousa
- Newborn Screening, Metabolism & Genetics Unit, Human Genetics Department, National Institute of Health Dr Ricardo Jorge, Porto, Portugal
| | - H Fonseca
- Newborn Screening, Metabolism & Genetics Unit, Human Genetics Department, National Institute of Health Dr Ricardo Jorge, Porto, Portugal
| | - C Valongo
- Newborn Screening, Metabolism & Genetics Unit, Human Genetics Department, National Institute of Health Dr Ricardo Jorge, Porto, Portugal
| | - L Vilarinho
- Newborn Screening, Metabolism & Genetics Unit, Human Genetics Department, National Institute of Health Dr Ricardo Jorge, Porto, Portugal
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Sajan A, Birke RL. The Reductive Cleavage Mechanism and Complex Stability of Glutathionyl-Cobalamin in Acidic Media. ELECTROANAL 2016. [DOI: 10.1002/elan.201600341] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Abin Sajan
- Department of Chemistry and Biochemistry; The City College of the City University of New York; NY 10031 USA
| | - Ronald L. Birke
- Department of Chemistry and Biochemistry; The City College of the City University of New York; NY 10031 USA
- Ph. D. Program in Chemistry; The Graduate Center of the City University of New York; 10016 USA
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Hannibal L, Lysne V, Bjørke-Monsen AL, Behringer S, Grünert SC, Spiekerkoetter U, Jacobsen DW, Blom HJ. Biomarkers and Algorithms for the Diagnosis of Vitamin B12 Deficiency. Front Mol Biosci 2016; 3:27. [PMID: 27446930 PMCID: PMC4921487 DOI: 10.3389/fmolb.2016.00027] [Citation(s) in RCA: 174] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 06/07/2016] [Indexed: 12/12/2022] Open
Abstract
Vitamin B12 (cobalamin, Cbl, B12) is an indispensable water-soluble micronutrient that serves as a coenzyme for cytosolic methionine synthase (MS) and mitochondrial methylmalonyl-CoA mutase (MCM). Deficiency of Cbl, whether nutritional or due to inborn errors of Cbl metabolism, inactivate MS and MCM leading to the accumulation of homocysteine (Hcy) and methylmalonic acid (MMA), respectively. In conjunction with total B12 and its bioactive protein-bound form, holo-transcobalamin (holo-TC), Hcy, and MMA are the preferred serum biomarkers utilized to determine B12 status. Clinically, vitamin B12 deficiency leads to neurological deterioration and megaloblastic anemia, and, if left untreated, to death. Subclinical vitamin B12 deficiency (usually defined as a total serum B12 of <200 pmol/L) presents asymptomatically or with rather subtle generic symptoms that oftentimes are mistakenly ascribed to unrelated disorders. Numerous studies have now established that serum vitamin B12 has limited diagnostic value as a stand-alone marker. Low serum levels of vitamin B12 not always represent deficiency, and likewise, severe functional deficiency of the micronutrient has been documented in the presence of normal and even high levels of serum vitamin B12. This review discusses the usefulness and limitations of current biomarkers of B12 status in newborn screening, infant and adult diagnostics, the algorithms utilized to diagnose B12 deficiency and unusual findings of vitamin B12 status in various human disorders.
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Affiliation(s)
- Luciana Hannibal
- Laboratory of Clinical Biochemistry and Metabolism, Department for Pediatrics, Medical Center, University of Freiburg Freiburg, Germany
| | - Vegard Lysne
- Department of Clinical Sciences, University of Bergen Bergen, Norway
| | | | - Sidney Behringer
- Laboratory of Clinical Biochemistry and Metabolism, Department for Pediatrics, Medical Center, University of Freiburg Freiburg, Germany
| | - Sarah C Grünert
- Laboratory of Clinical Biochemistry and Metabolism, Department for Pediatrics, Medical Center, University of Freiburg Freiburg, Germany
| | - Ute Spiekerkoetter
- Laboratory of Clinical Biochemistry and Metabolism, Department for Pediatrics, Medical Center, University of Freiburg Freiburg, Germany
| | - Donald W Jacobsen
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Cleveland, OH, USA
| | - Henk J Blom
- Laboratory of Clinical Biochemistry and Metabolism, Department for Pediatrics, Medical Center, University of Freiburg Freiburg, Germany
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Neuregulin 1 Promotes Glutathione-Dependent Neuronal Cobalamin Metabolism by Stimulating Cysteine Uptake. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2016:3849087. [PMID: 27057274 PMCID: PMC4709767 DOI: 10.1155/2016/3849087] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Revised: 10/10/2015] [Accepted: 10/12/2015] [Indexed: 01/12/2023]
Abstract
Neuregulin 1 (NRG-1) is a key neurotrophic factor involved in energy homeostasis and CNS development, and impaired NRG-1 signaling is associated with neurological disorders. Cobalamin (Cbl), also known as vitamin B12, is an essential micronutrient which mammals must acquire through diet, and neurologic dysfunction is a primary clinical manifestation of Cbl deficiency. Here we show that NRG-1 stimulates synthesis of the two bioactive Cbl species adenosylcobalamin (AdoCbl) and methylcobalamin (MeCbl) in human neuroblastoma cells by both promoting conversion of inactive to active Cbl species and increasing neuronal Cbl uptake. Formation of active Cbls is glutathione- (GSH-) dependent and the NRG-1-initiated increase is dependent upon its stimulation of cysteine uptake by excitatory amino acid transporter 3 (EAAT3), leading to increased GSH. The stimulatory effect of NRG-1 on cellular Cbl uptake is associated with increased expression of megalin, which is known to facilitate Cbl transport in ileum and kidney. MeCbl is a required cofactor for methionine synthase (MS) and we demonstrate the ability of NRG-1 to increase MS activity, and affect levels of methionine methylation cycle metabolites. Our results identify novel neuroprotective roles of NRG-1 including stimulating antioxidant synthesis and promoting active Cbl formation.
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Abstract
Approximately 50% of all congenital anomalies cannot be linked to any specific genetic etiology, but in recent years cost effective high throughput sequencing has emerged as an efficient strategy for identifying single nucleotide polymorphisms (SNPs) associated with disease. However, in many cases there is not enough evidence to determine if these SNPs underlie disease. To bridge this gap in our understanding advances in functional analyses are warranted. Several preclinical model systems are currently being utilized to provide such evidence, including the advantageous zebrafish embryo. While every system exhibits disadvantages and caveats, a new era of multidisciplinary research has evolved, which uses a broad spectrum of functional analysis tools. This approach will make it possible to identify potential therapeutic targets for both common and rare human disorders.
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Affiliation(s)
- Anita M Quintana
- Department of Biological Sciences, The University of Texas at El Paso, 500 West University Avenue, El Paso TX 79934
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Froese DS, Kopec J, Fitzpatrick F, Schuller M, McCorvie TJ, Chalk R, Plessl T, Fettelschoss V, Fowler B, Baumgartner MR, Yue WW. Structural Insights into the MMACHC-MMADHC Protein Complex Involved in Vitamin B12 Trafficking. J Biol Chem 2015; 290:29167-77. [PMID: 26483544 PMCID: PMC4705923 DOI: 10.1074/jbc.m115.683268] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Indexed: 11/06/2022] Open
Abstract
Conversion of vitamin B12 (cobalamin, Cbl) into the cofactor forms methyl-Cbl (MeCbl) and adenosyl-Cbl (AdoCbl) is required for the function of two crucial enzymes, mitochondrial methylmalonyl-CoA mutase and cytosolic methionine synthase, respectively. The intracellular proteins MMACHC and MMADHC play important roles in processing and targeting the Cbl cofactor to its destination enzymes, and recent evidence suggests that they may interact while performing these essential trafficking functions. To better understand the molecular basis of this interaction, we have mapped the crucial protein regions required, indicate that Cbl is likely processed by MMACHC prior to interaction with MMADHC, and identify patient mutations on both proteins that interfere with complex formation, via different mechanisms. We further report the crystal structure of the MMADHC C-terminal region at 2.2 Å resolution, revealing a modified nitroreductase fold with surprising homology to MMACHC despite their poor sequence conservation. Because MMADHC demonstrates no known enzymatic activity, we propose it as the first protein known to repurpose the nitroreductase fold solely for protein-protein interaction. Using small angle x-ray scattering, we reveal the MMACHC-MMADHC complex as a 1:1 heterodimer and provide a structural model of this interaction, where the interaction region overlaps with the MMACHC-Cbl binding site. Together, our findings provide novel structural evidence and mechanistic insight into an essential biological process, whereby an intracellular "trafficking chaperone" highly specific for a trace element cofactor functions via protein-protein interaction, which is disrupted by inherited disease mutations.
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Affiliation(s)
- D Sean Froese
- From the Division of Metabolism and Children's Research Center, University Children's, Hospital, CH-8032 Zurich, Switzerland, radiz - Rare Disease Initiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, CH-8032 Zurich, Switzerland
| | - Jolanta Kopec
- the Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ, United Kingdom, and
| | - Fiona Fitzpatrick
- the Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ, United Kingdom, and
| | - Marion Schuller
- the Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ, United Kingdom, and
| | - Thomas J McCorvie
- the Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ, United Kingdom, and
| | - Rod Chalk
- the Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ, United Kingdom, and
| | - Tanja Plessl
- From the Division of Metabolism and Children's Research Center, University Children's, Hospital, CH-8032 Zurich, Switzerland
| | - Victoria Fettelschoss
- From the Division of Metabolism and Children's Research Center, University Children's, Hospital, CH-8032 Zurich, Switzerland
| | - Brian Fowler
- From the Division of Metabolism and Children's Research Center, University Children's, Hospital, CH-8032 Zurich, Switzerland
| | - Matthias R Baumgartner
- From the Division of Metabolism and Children's Research Center, University Children's, Hospital, CH-8032 Zurich, Switzerland, radiz - Rare Disease Initiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, CH-8032 Zurich, Switzerland, the Zurich Center for Integrative Human Physiology, University of Zurich, 8057 Zurich, Switzerland
| | - Wyatt W Yue
- the Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ, United Kingdom, and
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