1
|
Szabo E, Nagy B, Czajlik A, Komlodi T, Ozohanics O, Tretter L, Ambrus A. Mitochondrial Alpha-Keto Acid Dehydrogenase Complexes: Recent Developments on Structure and Function in Health and Disease. Subcell Biochem 2024; 104:295-381. [PMID: 38963492 DOI: 10.1007/978-3-031-58843-3_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
The present work delves into the enigmatic world of mitochondrial alpha-keto acid dehydrogenase complexes discussing their metabolic significance, enzymatic operation, moonlighting activities, and pathological relevance with links to underlying structural features. This ubiquitous family of related but diverse multienzyme complexes is involved in carbohydrate metabolism (pyruvate dehydrogenase complex), the citric acid cycle (α-ketoglutarate dehydrogenase complex), and amino acid catabolism (branched-chain α-keto acid dehydrogenase complex, α-ketoadipate dehydrogenase complex); the complexes all function at strategic points and also participate in regulation in these metabolic pathways. These systems are among the largest multienzyme complexes with at times more than 100 protein chains and weights ranging up to ~10 million Daltons. Our chapter offers a wealth of up-to-date information on these multienzyme complexes for a comprehensive understanding of their significance in health and disease.
Collapse
Affiliation(s)
- Eszter Szabo
- Department of Biochemistry, Semmelweis University, Budapest, Hungary
| | - Balint Nagy
- Department of Biochemistry, Semmelweis University, Budapest, Hungary
| | - Andras Czajlik
- Department of Biochemistry, Semmelweis University, Budapest, Hungary
| | - Timea Komlodi
- Department of Biochemistry, Semmelweis University, Budapest, Hungary
| | - Oliver Ozohanics
- Department of Biochemistry, Semmelweis University, Budapest, Hungary
| | - Laszlo Tretter
- Department of Biochemistry, Semmelweis University, Budapest, Hungary
| | - Attila Ambrus
- Department of Biochemistry, Semmelweis University, Budapest, Hungary.
| |
Collapse
|
2
|
Zeynalzadeh M, Tafazoli A, Aarabi A, Moghaddassian M, Ashrafzadeh F, Houshmand M, Taghehchian N, Abbaszadegan MR. Four novel mutations of the BCKDHA, BCKDHB and DBT genes in Iranian patients with maple syrup urine disease. J Pediatr Endocrinol Metab 2018; 31:205-212. [PMID: 29306928 DOI: 10.1515/jpem-2017-0305] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Accepted: 12/04/2017] [Indexed: 11/15/2022]
Abstract
BACKGROUND Maple syrup urine disease (MSUD) is a rare metabolic autosomal recessive disorder caused by dysfunction of the branched-chain α-ketoacid dehydrogenase (BCKDH) complex. Mutations in the BCKDHA, BCKDHB and DBT genes are responsible for MSUD. The current study analyzed seven Iranian MSUD patients genetically and explored probable correlations between their genotype and phenotype. METHODS The panel of genes, including BCKDHA, BCKDHB and DBT, was evaluated, using routine the polymerase chain reaction (PCR)-sequencing method. In addition, protein modeling (homology and threading modeling) of the deduced novel mutations was performed. The resulting structures were then analyzed, using state-of-the-art bioinformatics tools to better understand the structural and functional effects caused by mutations. RESULTS Seven mutations were detected in seven patients, including four novel pathogenic mutations in BCKDHA (c.1198delA, c.629C>T), BCKDHB (c.652C>T) and DBT (c.1150A>G) genes. Molecular modeling of the novel mutations revealed clear changes in the molecular energy levels and stereochemical traits of the modeled proteins, which may be indicative of strong correlations with the functional modifications of the genes. Structural deficiencies were compatible with the observed phenotypes. CONCLUSIONS Any type of MSUD can show heterogeneous clinical manifestations in different ethnic groups. Comprehensive molecular investigations would be necessary for differential diagnosis.
Collapse
Affiliation(s)
- Monica Zeynalzadeh
- Medical Genetics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.,Department of Genetics, University of North Carolina, Chapel Hill, NC, USA
| | - Alireza Tafazoli
- Medical Genetics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Azadeh Aarabi
- Division of Human Genetics, Immunology Research Center, Avicenna Research Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Morteza Moghaddassian
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, Faculty of Applied Science and Engineering, University of Toronto, Ontario, Canada
| | - Farah Ashrafzadeh
- Department of Pediatric Neurology, Qaem Medical Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Massoud Houshmand
- Department of Medical Genetics, National Institute for Genetic Engineering and Biotechnology, Tehran, Iran
| | - Negin Taghehchian
- Division of Human Genetics, Immunology Research Center, Avicenna Research Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammad Reza Abbaszadegan
- Medical Genetics Research Center and Division of Human Genetics, Immunology Research Center, Avicenna Research Institute, Mashhad University of Medical Sciences, Mashhad 9196773117, Iran
| |
Collapse
|
3
|
Abiri M, Karamzadeh R, Karimipoor M, Ghadami S, Alaei MR, Bagheri SD, Bagherian H, Setoodeh A, Noori-Daloii MR, Sirous Zeinali. Identification of six novel mutations in Iranian patients with maple syrup urine disease and their in silico analysis. Mutat Res 2016; 786:34-40. [PMID: 26901124 DOI: 10.1016/j.mrfmmm.2016.01.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 01/12/2016] [Accepted: 01/22/2016] [Indexed: 01/09/2023]
Abstract
Maple syrup urine disease (MSUD) is a rare inborn error of branched-chain amino acid metabolism. The disease prevalence is higher in populations with elevated rate of consanguineous marriages such as Iran. Different types of disease causing mutations have been previously reported in BCKDHA, BCKDHB, DBT and DLD genes known to be responsible for MSUD phenotype. In this study, two sets of multiplex polymorphic STR (Short Tandem Repeat) markers linked to the above genes were used to aid in homozygosity mapping in order to find probable pathogenic change(s) in the studied families. The families who showed homozygote haplotype for the BCKDHA gene were subsequently sequenced. Our findings showed that exons 2, 4 and 6 contain most of the mutations which are novel. The changes include two single nucleotide deletion (i.e. c. 143delT and c.702delT), one gross deletion covering the whole exon four c.(375+1_376-1)_(8849+1_885-1), two splice site changes (c.1167+1G>T, c. 288+1G>A), and one point mutation (c.731G>A). Computational approaches were used to analyze these two novel mutations in terms of their impact on protein structure. Computational structural modeling indicated that these mutations might affect structural stability and multimeric assembly of branched-chain α-keto acid dehydrogenase complex (BCKDC).
Collapse
Affiliation(s)
- Maryam Abiri
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Department of Molecular Medicine, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Razieh Karamzadeh
- Department of Molecular Systems Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran; Department of Biophysics, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | - Morteza Karimipoor
- Department of Molecular Medicine, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Shirin Ghadami
- Department of Molecular Medicine, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Mohammad Reza Alaei
- Pediatric Endocrinology and Metabolism, Mofid Children's Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Samira Dabagh Bagheri
- Dr. Zeinali's Medical Genetics Laboratory, Kawsar Human Genetics Research Center, Tehran, Iran
| | - Hamideh Bagherian
- Dr. Zeinali's Medical Genetics Laboratory, Kawsar Human Genetics Research Center, Tehran, Iran
| | - Aria Setoodeh
- Department of Pediatrics, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Sirous Zeinali
- Department of Molecular Medicine, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran; Dr. Zeinali's Medical Genetics Laboratory, Kawsar Human Genetics Research Center, Tehran, Iran.
| |
Collapse
|
4
|
Schröder-Tittmann K, Meyer D, Arens J, Wechsler C, Tietzel M, Golbik R, Tittmann K. Alternating Sites Reactivity Is a Common Feature of Thiamin Diphosphate-Dependent Enzymes As Evidenced by Isothermal Titration Calorimetry Studies of Substrate Binding. Biochemistry 2013; 52:2505-7. [DOI: 10.1021/bi301591e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kathrin Schröder-Tittmann
- Göttingen Center for
Molecular Biosciences, Georg-August-University Göttingen, Ernst-Caspari-Haus, Justus-von-Liebig-Weg 11, 37077 Göttingen,
Germany
| | - Danilo Meyer
- Göttingen Center for
Molecular Biosciences, Georg-August-University Göttingen, Ernst-Caspari-Haus, Justus-von-Liebig-Weg 11, 37077 Göttingen,
Germany
| | - Johannes Arens
- Göttingen Center for
Molecular Biosciences, Georg-August-University Göttingen, Ernst-Caspari-Haus, Justus-von-Liebig-Weg 11, 37077 Göttingen,
Germany
| | - Cindy Wechsler
- Göttingen Center for
Molecular Biosciences, Georg-August-University Göttingen, Ernst-Caspari-Haus, Justus-von-Liebig-Weg 11, 37077 Göttingen,
Germany
| | - Michael Tietzel
- Göttingen Center for
Molecular Biosciences, Georg-August-University Göttingen, Ernst-Caspari-Haus, Justus-von-Liebig-Weg 11, 37077 Göttingen,
Germany
| | - Ralph Golbik
- Martin-Luther University Halle-Wittenberg, 06120 Halle/Salle, Germany
| | - Kai Tittmann
- Göttingen Center for
Molecular Biosciences, Georg-August-University Göttingen, Ernst-Caspari-Haus, Justus-von-Liebig-Weg 11, 37077 Göttingen,
Germany
| |
Collapse
|
5
|
Nemeria NS, Arjunan P, Chandrasekhar K, Mossad M, Tittmann K, Furey W, Jordan F. Communication between thiamin cofactors in the Escherichia coli pyruvate dehydrogenase complex E1 component active centers: evidence for a "direct pathway" between the 4'-aminopyrimidine N1' atoms. J Biol Chem 2010; 285:11197-209. [PMID: 20106967 DOI: 10.1074/jbc.m109.069179] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Kinetic, spectroscopic, and structural analysis tested the hypothesis that a chain of residues connecting the 4'-aminopyrimidine N1' atoms of thiamin diphosphates (ThDPs) in the two active centers of the Escherichia coli pyruvate dehydrogenase complex E1 component provides a signal transduction pathway. Substitution of the three acidic residues (Glu(571), Glu(235), and Glu(237)) and Arg(606) resulted in impaired binding of the second ThDP, once the first active center was filled, suggesting a pathway for communication between the two ThDPs. 1) Steady-state kinetic and fluorescence quenching studies revealed that upon E571A, E235A, E237A, and R606A substitutions, ThDP binding in the second active center was affected. 2) Analysis of the kinetics of thiazolium C2 hydrogen/deuterium exchange of enzyme-bound ThDP suggests half-of-the-sites reactivity for the E1 component, with fast (activated site) and slow exchanging sites (dormant site). The E235A and E571A variants gave no evidence for the slow exchanging site, indicating that only one of two active sites is filled with ThDP. 3) Titration of the E235A and E237A variants with methyl acetylphosphonate monitored by circular dichroism suggested that only half of the active sites were filled with a covalent predecarboxylation intermediate analog. 4) Crystal structures of E235A and E571A in complex with ThDP revealed the structural basis for the spectroscopic and kinetic observations and showed that either substitution affects cofactor binding, despite the fact that Glu(235) makes no direct contact with the cofactor. The role of the conserved Glu(571) residue in both catalysis and cofactor orientation is revealed by the combined results for the first time.
Collapse
Affiliation(s)
- Natalia S Nemeria
- Department of Chemistry, Rutgers University, Newark, New Jersey 07102, USA
| | | | | | | | | | | | | |
Collapse
|
6
|
Kale S, Jordan F. Conformational ensemble modulates cooperativity in the rate-determining catalytic step in the E1 component of the Escherichia coli pyruvate dehydrogenase multienzyme complex. J Biol Chem 2009; 284:33122-9. [PMID: 19801660 DOI: 10.1074/jbc.m109.065508] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cooperativity is extensively used by enzymes, particularly those acting at key metabolic branch points, to "fine tune" catalysis. Thus, cooperativity and enzyme catalysis are intimately linked, yet their linkage is poorly understood. Here we show that negative cooperativity in the rate-determining step in the E1 component of the Escherichia coli pyruvate dehydrogenase multienzyme complex is an outcome of redistribution of a "rate-promoting" conformational pre-equilibrium. An array of biophysical and biochemical studies indicates that non-catalytic but conserved residues directly regulate the redistribution. Furthermore, factors such as ligands and temperature, individually or in concert, also strongly influence the redistribution. As a consequence, these factors also exert their influence on catalysis by profoundly influencing the pre-equilibrium facilitated dynamics of communication between multienzyme components. Our observations suggest a mode of cooperativity in the E1 component that is consistent with the dynamical hypothesis shown to satisfactorily explain cooperativity in many well studied enzymes. The results point to the likely existence of multiple modes of communication between subunits when the entire class of thiamin diphosphate-dependent enzymes is considered.
Collapse
Affiliation(s)
- Sachin Kale
- Department of Chemistry, Rutgers University, Newark, New Jersey 07102, USA
| | | |
Collapse
|
7
|
Kato M, Wynn RM, Chuang JL, Tso SC, Machius M, Li J, Chuang DT. Structural basis for inactivation of the human pyruvate dehydrogenase complex by phosphorylation: role of disordered phosphorylation loops. Structure 2009; 16:1849-59. [PMID: 19081061 DOI: 10.1016/j.str.2008.10.010] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2008] [Revised: 10/26/2008] [Accepted: 10/27/2008] [Indexed: 11/15/2022]
Abstract
We report the crystal structures of the phosporylated pyruvate dehydrogenase (E1p) component of the human pyruvate dehydrogenase complex (PDC). The complete phosphorylation at Ser264-alpha (site 1) of a variant E1p protein was achieved using robust pyruvate dehydrogenase kinase 4 free of the PDC core. We show that unlike its unmodified counterpart, the presence of a phosphoryl group at Ser264-alpha prevents the cofactor thiamine diphosphate-induced ordering of the two loops carrying the three phosphorylation sites. The disordering of these phosphorylation loops is caused by a previously unrecognized steric clash between the phosphoryl group at site 1 and a nearby Ser266-alpha, which nullifies a hydrogen-bonding network essential for maintaining the loop conformations. The disordered phosphorylation loops impede the binding of lipoyl domains of the PDC core to E1p, negating the reductive acetylation step. This results in the disruption of the substrate channeling in the PDC, leading to the inactivation of this catalytic machine.
Collapse
Affiliation(s)
- Masato Kato
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9038, USA
| | | | | | | | | | | | | |
Collapse
|
8
|
Pei XY, Titman CM, Frank RA, Leeper FJ, Luisi BF. Snapshots of catalysis in the E1 subunit of the pyruvate dehydrogenase multienzyme complex. Structure 2008; 16:1860-72. [PMID: 19081062 PMCID: PMC2663715 DOI: 10.1016/j.str.2008.10.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Revised: 09/10/2008] [Accepted: 10/01/2008] [Indexed: 11/15/2022]
Abstract
The pyruvate dehydrogenase multienzyme assembly (PDH) generates acetyl coenzyme A and reducing equivalents from pyruvate in a multiple-step process that is a nexus of central metabolism. We report crystal structures of the Geobacillus stearothermophilus PDH E1p subunit with ligands that mimic the prereaction complex and the postdecarboxylation product. The structures implicate residues that help to orient substrates, nurture intermediates, and organize surface loops so that they can engage a mobile lipoyl domain that receives the acetyl group and shuttles it to the next active site. The structural and enzymatic data suggest that H128beta performs a dual role: first, as electrostatic catalyst of the reaction of pyruvate with the thiamine cofactor; and second, as a proton donor in the second reaction of acetyl group with the lipoate. We also identify I206alpha as a key residue in mediating the conformation of active-site loops. We propose that a simple conformational flip of the H271alpha side chain assists transfer of the acetyl group from thiamine cofactor to lipoyl domain in synchrony with reduction of the dithiolane ring.
Collapse
Affiliation(s)
- Xue Yuan Pei
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
| | - Christopher M. Titman
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
| | - René A.W. Frank
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
| | - Finian J. Leeper
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Ben F. Luisi
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
| |
Collapse
|
9
|
Wynn RM, Kato M, Chuang JL, Tso SC, Li J, Chuang DT. Pyruvate dehydrogenase kinase-4 structures reveal a metastable open conformation fostering robust core-free basal activity. J Biol Chem 2008; 283:25305-25315. [PMID: 18658136 PMCID: PMC2533096 DOI: 10.1074/jbc.m802249200] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2008] [Revised: 07/23/2008] [Indexed: 02/04/2023] Open
Abstract
Human pyruvate dehydrogenase complex (PDC) is down-regulated by pyruvate dehydrogenase kinase (PDK) isoforms 1-4. PDK4 is overexpressed in skeletal muscle in type 2 diabetes, resulting in impaired glucose utilization. Here we show that human PDK4 has robust core-free basal activity, which is considerably higher than activity levels of other PDK isoforms stimulated by the PDC core. PDK4 binds the L3 lipoyl domain, but its activity is not significantly stimulated by any individual lipoyl domains or the core of PDC. The 2.0-A crystal structures of the PDK4 dimer with bound ADP reveal an open conformation with a wider active-site cleft, compared with that in the closed conformation epitomized by the PDK2-ADP structure. The open conformation in PDK4 shows partially ordered C-terminal cross-tails, in which the conserved DW (Asp(394)-Trp(395)) motif from one subunit anchors to the N-terminal domain of the other subunit. The open conformation fosters a reduced binding affinity for ADP, facilitating the efficient removal of product inhibition by this nucleotide. Alteration or deletion of the DW-motif disrupts the C-terminal cross-tail anchor, resulting in the closed conformation and the nearly complete inactivation of PDK4. Fluorescence quenching and enzyme activity data suggest that compounds AZD7545 and dichloroacetate lock PDK4 in the open and the closed conformational states, respectively. We propose that PDK4 with bound ADP exists in equilibrium between the open and the closed conformations. The favored metastable open conformation is responsible for the robust basal activity of PDK4 in the absence of the PDC core.
Collapse
Affiliation(s)
- R Max Wynn
- Department of Biochemistry, Dallas, Texas 75390-9038; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9038
| | - Masato Kato
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9038
| | | | - Shih-Chia Tso
- Department of Biochemistry, Dallas, Texas 75390-9038
| | - Jun Li
- Department of Biochemistry, Dallas, Texas 75390-9038
| | - David T Chuang
- Department of Biochemistry, Dallas, Texas 75390-9038; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9038.
| |
Collapse
|
10
|
Islam MM, Wallin R, Wynn RM, Conway M, Fujii H, Mobley JA, Chuang DT, Hutson SM. A novel branched-chain amino acid metabolon. Protein-protein interactions in a supramolecular complex. J Biol Chem 2007; 282:11893-903. [PMID: 17314104 DOI: 10.1074/jbc.m700198200] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The catabolic pathways of branched-chain amino acids have two common steps. The first step is deamination catalyzed by the vitamin B(6)-dependent branched-chain aminotransferase isozymes (BCATs) to produce branched-chain alpha-keto acids (BCKAs). The second step is oxidative decarboxylation of the BCKAs mediated by the branched-chain alpha-keto acid dehydrogenase enzyme complex (BCKD complex). The BCKD complex is organized around a cubic core consisting of 24 lipoate-bearing dihydrolipoyl transacylase (E2) subunits, associated with the branched-chain alpha-keto acid decarboxylase/dehydrogenase (E1), dihydrolipoamide dehydrogenase (E3), BCKD kinase, and BCKD phosphatase. In this study, we provide evidence that human mitochondrial BCAT (hBCATm) associates with the E1 decarboxylase component of the rat or human BCKD complex with a K(D) of 2.8 microM. NADH dissociates the complex. The E2 and E3 components do not interact with hBCATm. In the presence of hBCATm, k(cat) values for E1-catalyzed decarboxylation of the BCKAs are enhanced 12-fold. Mutations of hBCATm proteins in the catalytically important CXXC center or E1 proteins in the phosphorylation loop residues prevent complex formation, indicating that these regions are important for the interaction between hBCATm and E1. Our results provide evidence for substrate channeling between hBCATm and BCKD complex and formation of a metabolic unit (termed branched-chain amino acid metabolon) that can be influenced by the redox state in mitochondria.
Collapse
Affiliation(s)
- Mohammad Mainul Islam
- Department of Biochemistry, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA
| | | | | | | | | | | | | | | |
Collapse
|