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Shandilya M, Kumar G, Gomkale R, Singh S, Khan MA, Kateriya S, Kundu S. Multiple putative methemoglobin reductases in C. reinhardtii may support enzymatic functions for its multiple hemoglobins. Int J Biol Macromol 2021; 171:465-479. [PMID: 33428952 DOI: 10.1016/j.ijbiomac.2021.01.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 12/26/2020] [Accepted: 01/05/2021] [Indexed: 10/22/2022]
Abstract
The ubiquitous nature of hemoglobins, their presence in multiple forms and low cellular expression in organisms suggests alternative physiological functions of hemoglobins in addition to oxygen transport and storage. Previous research has proposed enzymatic function of hemoglobins such as nitric oxide dioxygenase, nitrite reductase and hydroxylamine reductase. In all these enzymatic functions, active ferrous form of hemoglobin is converted to ferric form and reconversion of ferric to ferrous through reduction partners is under active investigation. The model alga C. reinhardtii contains multiple globins and is thus expected to have multiple putative methemoglobin reductases to augment the physiological functions of the novel hemoglobins. In this regard, three putative methemoglobin reductases and three algal hemoglobins were characterized. Our results signify that the identified putative methemoglobin reductases can reduce algal methemoglobins in a nonspecific manner under in vitro conditions. Enzyme kinetics of two putative methemoglobin reductases with methemoglobins as substrates and in silico analysis support interaction between the hemoglobins and the two reduction partners as also observed in vitro. Our investigation on algal methemoglobin reductases underpins the valuable chemistry of nitric oxide with the newly discovered hemoglobins to ensure their physiological relevance, with multiple hemoglobins probably necessitating the presence of multiple reductases.
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Affiliation(s)
- Manish Shandilya
- Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India; Amity School of Applied Sciences, Amity University Haryana, Gurugram 122413, India
| | - Gaurav Kumar
- Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India
| | - Ridhima Gomkale
- Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India
| | - Swati Singh
- Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India
| | - Mohd Asim Khan
- Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India
| | - Suneel Kateriya
- School of Biotechnology, Jawaharlal Nehru University, New Delhi 110021, India
| | - Suman Kundu
- Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India.
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Gupta V, Kulkarni A, Warang P, Devendra R, Chiddarwar A, Kedar P. Mutation update: Variants of the CYB5R3 gene in recessive congenital methemoglobinemia. Hum Mutat 2020; 41:737-748. [PMID: 31898843 DOI: 10.1002/humu.23973] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 12/05/2019] [Accepted: 12/26/2019] [Indexed: 11/07/2022]
Abstract
NADH-cytochrome b5 reductase 3 deficiency is an important genetic cause of recessive congenital methemoglobinemia (RCM) and occurs worldwide in autosomal recessive inheritance. In this Mutation Update, we provide a comprehensive review of all the pathogenic mutations and their molecular pathology in RCM along with the molecular basis of RCM in 21 new patients from the Indian population, including four novel variants: c.103A>C (p.Thr35Pro), c.190C>G (p.Leu64Val), c.310G>T (p.Gly104Cys), and c.352C>T (p.His118Tyr). In this update, over 78 different variants have been described for RCM globally. Molecular modeling of all the variants reported in CYB5R3 justifies association with the varying severity of the disease. The majority of the mutations associated with the severe form with a neurological disorder (RCM Type 2) were associated with the FAD-binding domain of the protein while the rest were located in another domain of the protein (RCM Type 1).
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Affiliation(s)
- Vinod Gupta
- Department of Haematogenetics, ICMR-National Institute of Immunohaematology, King Edward Memorial Hospital Campus, Mumbai, India
| | - Anuja Kulkarni
- Department of Haematogenetics, ICMR-National Institute of Immunohaematology, King Edward Memorial Hospital Campus, Mumbai, India
| | - Prashant Warang
- Department of Haematogenetics, ICMR-National Institute of Immunohaematology, King Edward Memorial Hospital Campus, Mumbai, India
| | - Rati Devendra
- Department of Haematogenetics, ICMR-National Institute of Immunohaematology, King Edward Memorial Hospital Campus, Mumbai, India
| | - Ashish Chiddarwar
- Department of Haematogenetics, ICMR-National Institute of Immunohaematology, King Edward Memorial Hospital Campus, Mumbai, India
| | - Prabhakar Kedar
- Department of Haematogenetics, ICMR-National Institute of Immunohaematology, King Edward Memorial Hospital Campus, Mumbai, India
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Abstract
Cytochromes P450 (P450s) are hemoproteins catalyzing oxidative biotransformation of a vast array of natural and xenobiotic compounds. Reducing equivalents required for dioxygen cleavage and substrate hydroxylation originate from different redox partners including diflavin reductases, flavodoxins, ferredoxins and phthalate dioxygenase reductase (PDR)-type proteins. Accordingly, circumstantial analysis of structural and physicochemical features governing donor-acceptor recognition and electron transfer poses an intriguing challenge. Thus, conformational flexibility reflected by togging between closed and open states of solvent exposed patches on the redox components was shown to be instrumental to steered electron transmission. Here, the membrane-interactive tails of the P450 enzymes and donor proteins were recognized to be crucial to proper orientation toward each other of surface sites on the redox modules steering functional coupling. Also, mobile electron shuttling may come into play. While charge-pairing mechanisms are of primary importance in attraction and complexation of the redox partners, hydrophobic and van der Waals cohesion forces play a minor role in docking events. Due to catalytic plasticity of P450 enzymes, there is considerable promise in biotechnological applications. Here, deeper insight into the mechanistic basis of the redox machinery will permit optimization of redox processes via directed evolution and DNA shuffling. Thus, creation of hybrid systems by fusion of the modified heme domain of P450s with proteinaceous electron carriers helps obviate the tedious reconstitution procedure and induces novel activities. Also, P450-based amperometric biosensors may open new vistas in pharmaceutical and clinical implementation and environmental monitoring.
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Affiliation(s)
- Peter Hlavica
- Walther-Straub-Institut für Pharmakologie und Toxikologie der LMU, Goethestrasse 33, 80336, München, Germany,
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Galeeva NM, Nenasheva SA, Kleymenova IS, Polyakov AV. Novel large deletion c.22-1320_633+1224del in the CYB5R3 gene from patients with hereditary methemoglobinemia. RUSS J GENET+ 2012. [DOI: 10.1134/s1022795412110038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Abstract
Cytochrome b5 reductase is a flavoprotein that is produced as two different isoforms that have different localizations. The amphipathic microsomal isoform, found in all cell types with the exception of erythrocytes, consists of one hydrophobic membrane-anchoring domain and a larger hydrophilic flavin catalytic domain. The soluble cytochrome b5 reductase isoform, found in human erythrocytes, is a truncated protein that is encoded by an alternative transcript and consists of the larger domain only. Cytochrome b5 reductase is involved in the transfer of reducing equivalents from the physiological electron donor, NADH, via an FAD domain to the small molecules of cytochrome b5. This protein has received much attention from researchers due to its involvement in many oxidation and reduction reactions, such as the reduction of methemoglobin to hemoglobin. Autosomal cytochrome b5 reductase gene deficiency manifests with the accumulation of oxidized Fe+3 and recessive congenital methemoglobinemia in humans. In this article, we provide a comprehensive overview of the structure and function of cytochrome b5 reductase from different eukaryotic sources and its potential use in the food industry, biosensor, and diagnostic areas.
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Affiliation(s)
- Fatemeh Elahian
- Department of Pharmaceutical Biotechnology, School of Pharmacy, Zanjan University of Medical Sciences , Iran and
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Percy MJ, Barnes C, Crighton G, Leventer RJ, Wynn R, Lappin TR. Methemoglobin reductase deficiency: novel mutation is associated with a disease phenotype of intermediate severity. J Pediatr Hematol Oncol 2012; 34:457-60. [PMID: 22627575 DOI: 10.1097/MPH.0b013e318257a492] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Cytochrome b5 reductase (CB5R) deficiency is a recessively inherited autosomal disorder that is either benign (type I) or associated with severe neurological problems (type II). Specific mutations in the CYB5R gene are not exclusive to each type. OBSERVATION Two cyanotic children with developmental delay but with slow progression were investigated for CB5R deficiency. A novel mutation, p.Arg58Pro, was independently detected in both cases. CONCLUSIONS The clinical variability and severity of the disease reflect the combined effects of impaired function of the 2 mutant enzymes. As illustrated by these 2 cases, inheritance of p.Arg58Pro with either p.Gly76Ser or pLeu188del causes a clinical condition more severe than type I and less severe than the type II cases reported to date.
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Lorenzo FR 5th, Phillips JD, Nussenzveig R, Lingam B, Koul PA, Schrier SL, Prchal JT. Molecular basis of two novel mutations found in type I methemoglobinemia. Blood Cells Mol Dis 2011; 46:277-81. [PMID: 21349748 DOI: 10.1016/j.bcmd.2011.01.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2011] [Accepted: 01/18/2011] [Indexed: 11/22/2022]
Abstract
Congenital methemoglobinemia due to NADH-cytochrome b5 reductase 3 (CYB5R3) deficiency is an autosomal recessive disorder that occurs sporadically worldwide, although endemic clusters of this disorder have been identified in certain ethnic groups. It is present as two distinct phenotypes, type I and type II. Type I methemoglobinemia is characterized by CYB5R3 enzyme deficiency restricted to erythrocytes and is associated with benign cyanosis. The less frequent type II methemoglobinemia is associated with generalized CYB5R3 deficiency affecting all cells and is lethal in early infancy. Here we describe the molecular basis of type I methemoglobinemia due to CYB5R3 deficiency in four patients from three distinct ethnic backgrounds, Asian Indian, Mexican and Greek. The CYB5R3 gene of three probands with type I methemoglobinemia and their relatives were sequenced revealing several putative causative mutations; in one subject multiple mutations were present. Two novel mutations, S54R and F157C, were identified and the previously described A179T, V253M mutations were also identified. All these point mutations mapped to the NADH binding domain and or the FAD binding domain. Each has the potential to sterically hinder cofactor binding causing instability of the CYB5R3 protein. Wild-type CYB5R3, as well as two of these novel mutations, S54R and F157C, was amplified, cloned, and purified recombinant peptide obtained. Kinetic and thermodynamic studies of these proteins show that the above mutations lead to decreased thermal stability.
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Mirzaei SA, Yazdi MT, Sepehrizadeh Z. Secretory expression and purification of a soluble NADH cytochrome b5 reductase enzyme from Mucor racemosus in Pichia pastoris based on codon usage adaptation. Biotechnol Lett 2010; 32:1705-11. [DOI: 10.1007/s10529-010-0348-z] [Citation(s) in RCA: 11] [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] [Received: 06/14/2010] [Accepted: 06/29/2010] [Indexed: 11/30/2022]
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Kahraman A, Morris RJ, Laskowski RA, Favia AD, Thornton JM. On the diversity of physicochemical environments experienced by identical ligands in binding pockets of unrelated proteins. Proteins 2010; 78:1120-36. [PMID: 19927322 DOI: 10.1002/prot.22633] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Most function prediction methods that identify cognate ligands from binding site analyses work on the assumption of molecular complementarity. These approaches build on the conjectured complementarity of geometrical and physicochemical properties between ligands and binding sites so that similar binding sites will bind similar ligands. We found that this assumption does not generally hold for protein-ligand interactions and observed that it is not the chemical composition of ligand molecules that dictates the complementarity between protein and ligand molecules, but that the ligand's share within the functional mechanism of a protein determines the degree of complementarity. Here, we present for a set of cognate ligands a descriptive analysis and comparison of the physicochemical properties that each ligand experiences in various nonhomologous binding pockets. The comparisons in each ligand set reveal large variations in their experienced physicochemical properties, suggesting that the same ligand can bind to distinct physicochemical environments. In some protein ligand complexes, the variation was found to correlate with the electrochemical characteristic of ligand molecules, whereas in others it was disclosed as a prerequisite for the biochemical function of the protein. To achieve binding, proteins were observed to engage in subtle balancing acts between electrostatic and hydrophobic interactions to generate stabilizing free energies of binding. For the presented analysis, a new method for scoring hydrophobicity from molecular environments was developed showing high correlations with experimental determined desolvation energies. The presented results highlight the complexities of molecular recognition and underline the challenges of computational structural biology in developing methods to detect these important subtleties.
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Affiliation(s)
- Abdullah Kahraman
- European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire CB10 1SD, United Kingdom.
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Nishimura Y, Shibuya M, Muraki A, Takeuchi F, Park SY, Tsubaki M. Structural and mechanistic roles of three consecutive Pro residues of porcine NADH-cytochrome b(5) reductase for the binding of beta-NADH. J Biosci Bioeng 2010; 108:286-92. [PMID: 19716516 DOI: 10.1016/j.jbiosc.2009.04.008] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Revised: 04/09/2009] [Accepted: 04/09/2009] [Indexed: 11/18/2022]
Abstract
Well-conserved three consecutive Pro residues (Pro247-249) in the NADH-binding subdomain of NADH-cytochrome b(5) reductase were proposed to form a basal part of the NADH-binding site. To investigate the structural and mechanistic roles of these residues, we expressed site-directed mutants for a soluble domain of the porcine enzyme where each of the residues was replaced with either Ala or Leu residue, respectively, using a heterologous expression system in Escherichia coli. Six mutants (P247A, P247L, P248A, P248L, P249A, and P249L) were produced as a fusion protein containing a 6xHis-tag sequence at the NH(2)-terminus and were purified to homogeneity with a stoichiometric amount of bound FAD. Mutations were each confirmed for the purified proteins by MALDI-TOF mass spectrometry. Steady-state kinetic analyses for NADH:ferricyanide reductase and NADH:cytochrome b(5) reductase acitivities were conducted for all the mutants. Substitution of Pro247 with Leu residue was found to significantly decrease k(cat) with slight increase in K(m) for the physiological electron donor NADH. However, K(m) values for the electron acceptors (both cytochrome b(5) and ferricyanide) of P247L were found to be decreased significantly. Such changes were not observed for P247A or other four mutants. These results suggested that Pro247 among the three consecutive Pro residues has the most important role for the formation of a binding site cavity and that only a slight change in the side-chain volume at this residue from Ala to Leu residue affected the electron transfer reaction from NADH and, further, on the recognition of ferricytochrome b(5).
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Affiliation(s)
- Yuka Nishimura
- Department of Molecular Science and Material Engineering, Kobe University, Rokkodai-cho, Nada-ku, Hyogo, Japan
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Kedar PS, Warang P, Nadkarni AH, Colah RB, Ghosh K. A novel G143D mutation in the NADH-cytochrome b5 reductase gene in an Indian patient with type I recessive hereditary methemoglobinemia. Blood Cells Mol Dis 2008; 40:323-7. [DOI: 10.1016/j.bcmd.2007.09.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2007] [Revised: 09/11/2007] [Accepted: 09/12/2007] [Indexed: 11/20/2022]
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12
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Fermo E, Bianchi P, Vercellati C, Marcello AP, Garatti M, Marangoni O, Barcellini W, Zanella A. Recessive hereditary methemoglobinemia: two novel mutations in the NADH-cytochrome b5 reductase gene. Blood Cells Mol Dis 2008; 41:50-5. [PMID: 18343696 DOI: 10.1016/j.bcmd.2008.02.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 02/06/2008] [Accepted: 02/06/2008] [Indexed: 10/22/2022]
Abstract
We report the clinical and molecular characteristics of 6 new patients with recessive hereditary methemoglobinemia due to cytochrome b5 reductase deficiency. One patient was affected by Type-II disease with cyanosis and severe progressive neurological dysfunction, whereas the others displayed the benign Type-I phenotype. Methemoglobin levels ranged from 12.1% to 26.2% and cytochrome b5 reductase activity from 0 to 10% of normal. Eight different mutations were detected among the twelve mutated alleles identified, one splicing mutation, two stop codon, and five missense. Two mutations c. 82 C>T(Gln27STOP) and c. 136 C>T(Arg45Trp) are new. Prenatal diagnosis was performed in the family with Type-II disease.
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Affiliation(s)
- Elisa Fermo
- U.O. Ematologia 2, Fondazione IRCCS Ospedale Maggiore, Mangiagalli e Regina Elena, Via F. Sforza, 35, 20122 Milano, Italy
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Abstract
Some 60 years ago, Quentin Gibson reported the first hereditary disorder involving an enzyme when he deduced that familial methaemoglobinaemia was caused by an enzymatic lesion associated with the glycolysis pathway in red blood cells. This disorder, now known as recessive congenital methaemoglobinaemia (RCM), is caused by NADH-cytochrome b5 reductase (cb(5)r) deficiency. Two distinct clinical forms, types I and II, have been recognized, both characterized by cyanosis from birth. In type II, the cyanosis is accompanied by neurological impairment and reduced life expectancy. Cytochrome b(5) reductase is composed of one FAD and one NADH binding domain linked by a hinge region. It is encoded by the CYB5R3 (previously known as DIA1) gene and more than 40 mutations have been described, some of which are common to both types of RCM. Mutations associated with type II tend to cause incorrect splicing, disruption of the active site or truncation of the protein. At present the description of the sequence variants of cb(5)r in the literature is confusing, due to the use of two conventions which differ by one codon position. Herein we propose a new system for nomenclature of cb(5)r based on recommendations of the Human Genome Variation Society. The development of a heterologous expression system has allowed the impact of naturally occurring variants of cb(5)r to be assessed and has provided insight into the function of cb(5)r.
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Kurian JR, Longlais BJ, Trepanier LA. Discovery and characterization of a cytochrome b5 variant in humans with impaired hydroxylamine reduction capacity. Pharmacogenet Genomics 2007; 17:597-603. [PMID: 17622936 DOI: 10.1097/fpc.0b013e328011aaff] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES We have shown that cytochrome b5 (cyt b5), along with its reductase, NADH cytochrome b5 reductase (b5R), is capable of direct xenobiotic biotransformation. We hypothesized that functionally significant genetic variability in cyt b5 could be found in healthy individuals. BASIC METHODS Cyt b5 cDNAs were prepared from peripheral blood mononuclear cells from 63 individuals. MAIN RESULTS One individual was heterozygous for a sequence variant in cyt b5 (A178G), with a predicted amino acid substitution of T60A. This variant, when expressed in Escherichia. coli, maintained a similar Vmax for the hydroxylamines of sulfamethoxazole, 4-aminobiphenyl, and 2-amino-l-methyl-6-phenylimidazo[4,5-b] pyridine (PhIP), compared with wild type cyt b5, with a modestly increased Km (2 to 3.5-fold) for each substrate. When expressed in a mammalian system (HeLa cells), however, T60A was associated with a 70% reduction in cyt b5 protein expression compared with wild type. mRNA expression for both isoforms were comparable in HeLa cells, and translation of these mRNAs in a rabbit reticulocyte lysate system with inhibited proteasomal machinery were also similar. Incubation of these translated enzymes with uninhibited rabbit reticulocyte lysate, however, indicated greater susceptibility of T60A to proteasomal degradation. CONCLUSIONS These data indicate that a naturally occurring variant in cyt b5, T60A, leads to modestly altered affinity for hydroxylamine substrates and dramatically reduced cyt b5 expression. Work is underway to determine the prevalence of this and other variants in cyt b5 or b5R in a larger population, and to determine the association of such variants with differences in hydroxylamine reduction in vivo.
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Affiliation(s)
- Joseph R Kurian
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, USA
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