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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: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Zhukov S, Eder-Goy D, Fedosov S, Xu BX, von Seggern H. Analytical prediction of the piezoelectric d 33 response of fluoropolymer arrays with tubular air channels. Sci Rep 2018; 8:4597. [PMID: 29545636 PMCID: PMC5854664 DOI: 10.1038/s41598-018-22918-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 03/02/2018] [Indexed: 11/09/2022] Open
Abstract
The present study is focused on tubular multi-channel arrays composed of commercial fluoropolymer (FEP) tubes with different wall thickness. After proper charging in a high electric field, such tubular structures exhibit a large piezoelectric [Formula: see text] coefficient significantly exceeding the values of classical polymer ferroelectrics and being even comparable to conventional lead-free piezoceramics. The quasistatic piezoelectric [Formula: see text] coefficient was theoretically derived and its upper limits were evaluated considering charging and mechanical properties of the arrays. In order to optimize the [Formula: see text] coefficient the remanent polarization and the mechanical properties were taken into account, both being strongly dependent on the air channel geometry as well as on the wall thickness of the FEP tubes. The model predictions are compared with experimental d33 coefficients for two particular arrays with equal air gaps of 250 μm, but with different wall thickness of utilized FEP tubes of 50 μm and 120 μm, respectively. Analytical modeling allows for the prediction that arrays made of FEP tubes with a wall thickness of 10 μm are foreseen to exhibit a superb piezoelectric response of up to 600 pC/N if the height of stadium-like shaped air channels is reduced down to 50 μm, making them potentially interesting for application as highly sensitive sensors and energy harvesting.
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Affiliation(s)
- Sergey Zhukov
- Institut für Materialwissenschaft, Technische Universität Darmstadt, Alarich-Weiss-Straße 2, Darmstadt, 64287, Germany.
| | - Dagmar Eder-Goy
- Institut für Materialwissenschaft, Technische Universität Darmstadt, Otto-Berndt-Straße 3, Darmstadt, 64287, Germany
| | - Sergey Fedosov
- Department of Physics and Materials Science, Odessa National Academy of Food Technologies, ul. Kanatnaya 112, Odessa, 65039, Ukraine
| | - Bai-Xiang Xu
- Institut für Materialwissenschaft, Technische Universität Darmstadt, Otto-Berndt-Straße 3, Darmstadt, 64287, Germany
| | - Heinz von Seggern
- Institut für Materialwissenschaft, Technische Universität Darmstadt, Alarich-Weiss-Straße 2, Darmstadt, 64287, Germany
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Mutti E, Hunger M, Fedosov S, Nexo E, Kräutler B. Organometallic DNA-B 12 Conjugates as Potential Oligonucleotide Vectors: Synthesis and Structural and Binding Studies with Human Cobalamin-Transport Proteins. Chembiochem 2017; 18:2280-2291. [PMID: 28881087 DOI: 10.1002/cbic.201700472] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Indexed: 12/14/2022]
Abstract
The synthesis and structural characterization of Co-(dN)25 -Cbl (Cbl: cobalamin; dN: deoxynucleotide) and Co-(dN)39 -Cbl, which are organometallic DNA-B12 conjugates with single DNA strands consisting of 25 and 39 deoxynucleotides, respectively, and binding studies of these two DNA-Cbl conjugates to three homologous human Cbl transporting proteins, transcobalamin (TC), intrinsic factor (IF), and haptocorrin (HC), are reported. This investigation tests the suitability of such DNA-Cbls for the task of eventual in vivo oligonucleotide delivery. The binding of DNA-Cbl to TC, IF, and HC was investigated in competition with either a fluorescent Cbl derivative and Co-(dN)25 -Cbl, or radiolabeled vitamin B12 (57 Co-CNCbl) and Co-(dN)25 -Cbl or Co-(dN)39 -Cbl. Binding of the new DNA-Cbl conjugates was fast and tight with TC, but poorer with HC and IF, which extends a similar original finding with the simpler DNA-Cbl, Co-(dN)18 -Cbl. The contrasting affinities of TC versus IF and HC for the DNA-Cbl conjugates are rationalized herein by a stepwise mechanism of Cbl binding. Critical contributions to overall affinity result from gradual conformational adaptations of the Cbl-binding proteins to the DNA-Cbl, which is first bound to the respective β domains. This transition is fast with TC, but slow with IF and HC, with which weaker binding results. The invariably tight interaction of the DNA-Cbl conjugates with TC makes the Cbl moiety a potential natural vector for the specific delivery of oligonucleotide loads from the blood into cells.
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Affiliation(s)
- Elena Mutti
- Department of Clinical Biochemistry, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Miriam Hunger
- Institute of Organic Chemistry, Center for Molecular Biosciences (CMBI), University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria
| | - Sergey Fedosov
- Department of Molecular Biology and Genetics, Aarhus University, Science Park Gustav WiedsVej 10C, 8000, Aarhus C, Denmark
| | - Ebba Nexo
- Department of Clinical Biochemistry, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Bernhard Kräutler
- Institute of Organic Chemistry, Center for Molecular Biosciences (CMBI), University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria
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Firdaus MY, Brask J, Nielsen PM, Guo Z, Fedosov S. Kinetic model of biodiesel production catalyzed by free liquid lipase from Thermomyces lanuginosus. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.molcatb.2016.07.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Brito A, Miller J, Green R, Fedosov S, Harvey D, Shahab‐Ferdows S, Verdugo R, Sanchez H, Albala C, Uauy R, Allen L. Effect of vitamin B12 supplementation on B12 status and neurophysiological function in older Chileans analyzed by the combined indicator of B12 status. FASEB J 2015. [DOI: 10.1096/fasebj.29.1_supplement.28.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Li W, Fedosov S, Tan T, Xu X, Guo Z. Naturally occurring alkaline amino acids function as efficient catalysts on Knoevenagel condensation at physiological pH: a mechanistic elucidation. Appl Biochem Biotechnol 2014; 173:278-90. [PMID: 24682854 DOI: 10.1007/s12010-014-0840-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Accepted: 02/27/2014] [Indexed: 11/24/2022]
Abstract
To maintain biological functions, thousands of different reactions take place in human body at physiological pH (7.0) and mild conditions, which is associated with health and disease. Therefore, to examine the catalytic function of the intrinsically occurring molecules, such as amino acids at neutral pH, is of fundamental interests. Natural basic α-amino acid of L-lysine, L-arginine, and L-histidine neutralized to physiological pH as salts were investigated for their ability to catalyze Knoevenagel condensation of benzaldehyde and ethyl cyanoacetate. Compared with their free base forms, although neutralized alkaline amino acid salts reduced the catalytic activity markedly, they were still capable to perform an efficient catalysis at physiological pH as porcine pancreatic lipase (PPL), one of the best enzymes that catalyze Knoevenagel condensation. In agreement with the fact that the three basic amino acids were well neutralized, stronger basic amino acid Arg and Lys showed more obvious variation in NH bend peak from the FTIR spectroscopy study. Study of ethanol/water system and quantitative kinetic analysis suggested that the microenvironment in the vicinity of amino acid salts and protonability/deprotonability of the amine moiety may determine their catalytic activity and mechanism. The kinetic study of best approximation suggested that the random binding might be the most probable catalytic mechanism for the neutralized alkaline amino acid salt-catalyzed Knoevenagel condensation.
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Affiliation(s)
- Weina Li
- Department of Engineering, Aarhus University, Aarhus, Denmark
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Brito A, Miller J, Fedosov S, Shahab‐Ferdows S, Sanchez H, Albala C, Uauy R, Allen L. Low vitamin B12 status and less response to vitamin B12 treatment in Chilean B12‐deficient elderly with high serum folate (135.8). FASEB J 2014. [DOI: 10.1096/fasebj.28.1_supplement.135.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | | | - Hugo Sanchez
- Institute of Nutrition and Food TechnologyUniversity of ChileSantiagoChile
| | - Cecilia Albala
- Institute of Nutrition and Food TechnologyUniversity of ChileSantiagoChile
| | - Ricardo Uauy
- Institute of Nutrition and Food TechnologyUniversity of ChileSantiagoChile
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Dilis V, Vasilopoulou E, Alexieva I, Boyko N, Bondrea A, Fedosov S, Hayran O, Jorjadze M, Karpenko D, Costa HS, Finglas P, Trichopoulou A. Definition and documentation of traditional foods of the Black Sea Area Countries: potential nutrition claims. J Sci Food Agric 2013; 93:3473-3477. [PMID: 23712943 DOI: 10.1002/jsfa.6238] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 04/18/2013] [Accepted: 05/24/2013] [Indexed: 06/02/2023]
Abstract
BACKGROUND Nutrition and health claims are permitted in foods marketed in the European Union under Regulation 1924/2006. Quality products such as traditional foods might benefit from this act, as it can highlight their nutritional richness. In this study the nutritional content of 33 traditional foods from the Black Sea Area Countries was evaluated against the thresholds of the Regulation for nutrition claims. RESULTS Most of the foods were eligible to bear several nutrition claims, mostly related to their fat, sugar, fiber and sodium content. The average number of claims per traditional food was two, with a range between zero and nine. Overall, about 72 nutrition claims were potentially relevant for the 33 traditional foods studied. Foods linked with the most claims were nuts and seeds. CONCLUSION The inclusion of traditional foods under this standardized European scheme could be an efficient way to highlight their possible beneficial nutritional properties. The production and marketing of traditional foods could be of benefit to both the health of consumers and the economic viability of producers, especially small- and medium-size enterprises.
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Kaprelyants L, Fedosov S, Zhygunov D. Baking properties and biochemical composition of wheat flour with bran and shorts. J Sci Food Agric 2013; 93:3611-3616. [PMID: 23893333 DOI: 10.1002/jsfa.6320] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 06/06/2013] [Accepted: 07/25/2013] [Indexed: 06/02/2023]
Abstract
BACKGROUND Bran, being a by-product of grain grinding, is characterised by a high biological value and is thus widely used in food production. In this study, different streams of bran and shorts from the wheat graded milling process were incorporated into wheat flour at levels of 5, 11, 17 and 23% (w/w) to investigate their influence on the nutritional and baking properties of flour. RESULTS Bran and shorts streams improved the baking properties of flour blends. The best result in the case of graded flour blends with different bran products was obtained at the 95:5 ratio. The products containing peripheral parts of grain had higher proteolytic enzyme and superoxide dismutase activities and lower trypsin inhibitor content and β-amylase activity compared with graded flour. CONCLUSION Streams of wheat milled fractions including peripheral parts of grain increase the content of bioactive substances and dietary fibre in blends with wheat graded flour.
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Affiliation(s)
- Leonid Kaprelyants
- Department of Biochemistry and Microbiology, Odessa National Academy of Food Technologies, Odessa, Ukraine
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Ruetz M, Salchner R, Wurst K, Fedosov S, Kräutler B. Phenylethinylcobalamin: ein radikalsynthetisch hergestelltes, lichtstabiles und hitzeresistentes metallorganisches B12-Derivat. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201305206] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Ruetz M, Salchner R, Wurst K, Fedosov S, Kräutler B. Phenylethynylcobalamin: A Light-Stable and Thermolysis-Resistant Organometallic Vitamin B12Derivative Prepared by Radical Synthesis. Angew Chem Int Ed Engl 2013; 52:11406-9. [DOI: 10.1002/anie.201305206] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Indexed: 11/10/2022]
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Ruetz M, Gherasim C, Gruber K, Fedosov S, Banerjee R, Kräutler B. Inside Cover: Access to Organometallic Arylcobaltcorrins through Radical Synthesis: 4-Ethylphenylcobalamin, a Potential “Antivitamin B 12” (Angew. Chem. Int. Ed. 9/2013). Angew Chem Int Ed Engl 2013. [DOI: 10.1002/anie.201300393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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13
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Ruetz M, Gherasim C, Gruber K, Fedosov S, Banerjee R, Kräutler B. Innentitelbild: Zugang zu metallorganischen Arylcobaltcorrinen durch radikalische Synthese: 4-Ethylphenylcobalamin, ein potenzielles “Antivitamin B 12” (Angew. Chem. 9/2013). Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201300393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Ruetz M, Gherasim C, Gruber K, Fedosov S, Banerjee R, Kräutler B. Access to organometallic arylcobaltcorrins through radical synthesis: 4-ethylphenylcobalamin, a potential "antivitamin B(12)". Angew Chem Int Ed Engl 2013; 52:2606-10. [PMID: 23404623 DOI: 10.1002/anie.201209651] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Indexed: 11/11/2022]
Abstract
Locked B(12): 4-Ethylphenylcobalamin, a novel organometallic arylcobalamin, has been synthesized in a radical reaction. This vitamin B(12) antimetabolite features a strong Co-C bond, and represents a "locked" form of vitamin B(12) . It may be used in animal studies to induce functional vitamin B(12) deficiency artificially to help clarify still controversial issues related to the pathophysiology of vitamin B(12) deficiency.
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Affiliation(s)
- Markus Ruetz
- Institute of Organic Chemistry and Centre of Molecular Biosciences, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
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Ruetz M, Gherasim C, Gruber K, Fedosov S, Banerjee R, Kräutler B. Zugang zu metallorganischen Arylcobaltcorrinen durch radikalische Synthese: 4-Ethylphenylcobalamin, ein potenzielles “Antivitamin B12”. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201209651] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Greibe E, Fedosov S, Sorensen BS, Højrup P, Poulsen SS, Nexo E. A single rainbow trout cobalamin-binding protein stands in for three human binders. J Biol Chem 2012; 287:33917-25. [PMID: 22872637 DOI: 10.1074/jbc.m112.398016] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cobalamin uptake and transport in mammals are mediated by three cobalamin-binding proteins: haptocorrin, intrinsic factor, and transcobalamin. The nature of cobalamin-binding proteins in lower vertebrates remains to be elucidated. The aim of this study was to characterize the cobalamin-binding proteins of the rainbow trout (Oncorhynchus mykiss) and to compare their properties with those of the three human cobalamin-binding proteins. High cobalamin-binding capacity was found in trout stomach (210 pmol/g), roe (400 pmol/g), roe fluid (390 nmol/liter), and plasma (2500 nmol/liter). In all cases, it appeared to be the same protein based on analysis of partial sequences and immunological responses. The trout cobalamin-binding protein was purified from roe fluid, sequenced, and further characterized. Like haptocorrin, the trout cobalamin-binding protein was stable at low pH and had a high binding affinity for the cobalamin analog cobinamide. Like haptocorrin and transcobalamin, the trout cobalamin-binding protein was present in plasma and recognized ligands with altered nucleotide moiety. Like intrinsic factors, the trout cobalamin-binding protein was present in the stomach and resisted degradation by trypsin and chymotrypsin. It also resembled intrinsic factor in the composition of conserved residues in the primary cobalamin-binding site in the C terminus. The trout cobalamin-binding protein was glycosylated and displayed spectral properties comparable with those of haptocorrin and intrinsic factor. In conclusion, only one soluble cobalamin-binding protein was identified in the rainbow trout, a protein that structurally behaves like an intermediate between the three human cobalamin-binding proteins.
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Affiliation(s)
- Eva Greibe
- Department of Clinical Biochemistry, Aarhus University Hospital, 8000 Aarhus, Denmark.
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Greibe E, Fedosov S, Nexo E. The cobalamin-binding protein in zebrafish is an intermediate between the three cobalamin-binding proteins in human. PLoS One 2012; 7:e35660. [PMID: 22532867 PMCID: PMC3331988 DOI: 10.1371/journal.pone.0035660] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Accepted: 03/20/2012] [Indexed: 12/30/2022] Open
Abstract
In humans, three soluble extracellular cobalamin-binding proteins; transcobalamin (TC), intrinsic factor (IF), and haptocorrin (HC), are involved in the uptake and transport of cobalamin. In this study, we investigate a cobalamin-binding protein from zebrafish (Danio rerio) and summarize current knowledge concerning the phylogenetic evolution of kindred proteins. We identified a cobalamin binding capacity in zebrafish protein extracts (8.2 pmol/fish) and ambient water (13.5 pmol/fish) associated with a single protein. The protein showed resistance toward degradation by trypsin and chymotrypsin (like human IF, but unlike human HC and TC). The cobalamin analogue, cobinamide, bound weaker to the zebrafish cobalamin binder than to human HC, but stronger than to human TC and IF. Affinity for another analogue, adenosyl-pseudo-cobalamin was low compared with human HC and TC, but high compared with human IF. The absorbance spectrum of the purified protein in complex with hydroxo-cobalamin resembled those of human HC and IF, but not TC. We searched available databases to further explore the phylogenies of the three cobalamin-binding proteins in higher vertebrates. Apparently, TC-like proteins are the oldest evolutionary derivatives followed by IF and HC (the latter being present only in reptiles and most but not all mammals). Our findings suggest that the only cobalamin-binding protein in zebrafish is an intermediate between the three human cobalamin binders. These findings support the hypothesis about a common ancestral gene for all cobalamin-binding proteins in higher vertebrates.
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Affiliation(s)
- Eva Greibe
- Department of Clinical Biochemistry, Aarhus University Hospital, Aarhus, Denmark.
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Lildballe DL, Fedosov S, Sherliker P, Hin H, Clarke R, Nexo E. Association of Cognitive Impairment with Combinations of Vitamin B12–Related Parameters. Clin Chem 2011; 57:1436-43. [DOI: 10.1373/clinchem.2011.165944] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND
Low vitamin B12 concentrations have been associated with higher risks of cognitive impairment, but whether these associations are causal is uncertain. The associations of cognitive impairment with combinations of vitamin B12, holotranscobalamin, methylmalonic acid, and total homocysteine, and with the vitamin B12 transport proteins transcobalamin and haptocorrin, have not been previously studied.
METHODS
We performed a population-based cross-sectional study of 839 people 75 years old or older. We examined the association of cognitive function as measured by mini–mental state examination scores, with markers of vitamin B12 status. Spearman correlations as well as multivariate-adjusted odds ratios and 95% CIs for cognitive impairment were calculated for extreme thirds of serum concentrations of vitamin B12, holotranscobalamin, methylmalonic acid, total homocysteine, combination of these markers in a wellness score, heaptocorrin, and transcobalamin for all data and with B12 analogs in a nested case-control study.
RESULTS
Cognitive impairment was significantly associated with low vitamin B12 [odds ratio 2.3 (95% CI 1.2–4.5)]; low holotranscobalamin [4.1 (2.0–8.7)], high methylmalonic acid [3.5 (1.8–7.1)], high homocysteine [4.8 (2.3–10.0)] and low wellness score [5.1 (2.61–10.46)]. After correction for relevant covariates, cognitive impairment remained significantly associated with high homocysteine [4.85 (2.24–10.53)] and with a low wellness score [5.60 (2.61–12.01)] but not with transcobalamin, haptocorrin, or analogs on haptocorrin.
CONCLUSIONS
Cognitive impairment was associated with the combined effects of the 4 biomarkers of vitamin B12 deficiency when included in a wellness score but was not associated with binding proteins or analogs on haptocorrin.
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Affiliation(s)
| | - Sergey Fedosov
- Institute of Molecular Biology, Aarhus University, Aarhus, Denmark
| | - Paul Sherliker
- Clinical Trial Service Unit, University of Oxford, Oxford, UK
| | - Harold Hin
- Hightown Surgery, Banbury, Oxfordshire, United Kingdom
| | - Robert Clarke
- Clinical Trial Service Unit, University of Oxford, Oxford, UK
| | - Ebba Nexo
- Department of Clinical Biochemistry, Aarhus University Hospital
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Quadros EV, Lai SC, Nakayama Y, Sequeira JM, Hannibal L, Wang S, Jacobsen DW, Fedosov S, Wright E, Gallagher RC, Anastasio N, Watkins D, Rosenblatt DS. Positive newborn screen for methylmalonic aciduria identifies the first mutation in TCblR/CD320, the gene for cellular uptake of transcobalamin-bound vitamin B(12). Hum Mutat 2010; 31:924-9. [PMID: 20524213 DOI: 10.1002/humu.21297] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Elevated methylmalonic acid in five asymptomatic newborns whose fibroblasts showed decreased uptake of transcobalamin-bound cobalamin (holo-TC), suggested a defect in the cellular uptake of cobalamin. Analysis of TCblR/CD320, the gene for the receptor for cellular uptake of holo-TC, identified a homozygous single codon deletion, c.262_264GAG (p.E88del), resulting in the loss of a glutamic acid residue in the low-density lipoprotein receptor type A-like domain. Inserting the codon by site-directed mutagenesis fully restored TCblR function.
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Affiliation(s)
- Edward V Quadros
- Department of Medicine, SUNY-Downstate Medical Center, Brooklyn, New York 11203, USA.
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