1
|
Antony P, Baby B, Ali A, Vijayan R, Al Jasmi F. Interaction of Glutathione with MMACHC Arginine-Rich Pocket Variants Associated with Cobalamin C Disease: Insights from Molecular Modeling. Biomedicines 2023; 11:3217. [PMID: 38137438 PMCID: PMC10740964 DOI: 10.3390/biomedicines11123217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 11/20/2023] [Accepted: 11/28/2023] [Indexed: 12/24/2023] Open
Abstract
Methylmalonic aciduria and homocystinuria type C protein (MMACHC) is required by the body to metabolize cobalamin (Cbl). Due to its complex structure and cofactor forms, Cbl passes through an extensive series of absorptive and processing steps before being delivered to mitochondrial methyl malonyl-CoA mutase and cytosolic methionine synthase. Depending on the cofactor attached, MMACHC performs either flavin-dependent reductive decyanation or glutathione (GSH)-dependent dealkylation. The alkyl groups of Cbl have to be removed in the presence of GSH to produce intermediates that can later be converted into active cofactor forms. Pathogenic mutations in the GSH binding site, such as R161Q, R161G, R206P, R206W, and R206Q, have been reported to cause Cbl diseases. The impact of these variations on MMACHC's structure and how it affects GSH and Cbl binding at the molecular level is poorly understood. To better understand the molecular basis of this interaction, mutant structures involving the MMACHC-MeCbl-GSH complex were generated using in silico site-directed point mutations and explored using molecular dynamics (MD) simulations. The results revealed that mutations in the key arginine residues disrupt GSH binding by breaking the interactions and reducing the free energy of binding of GSH. Specifically, variations at position 206 appeared to produce weaker GSH binding. The lowered binding affinity for GSH in the variant structures could impact metabolic pathways involving Cbl and its trafficking.
Collapse
Affiliation(s)
- Priya Antony
- Department of Biology, College of Science, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
| | - Bincy Baby
- Department of Biology, College of Science, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
| | - Amanat Ali
- Department of Genetics and Genomics, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
| | - Ranjit Vijayan
- Department of Biology, College of Science, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
- The Big Data Analytics Center, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
- Zayed Center for Health Sciences, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
| | - Fatma Al Jasmi
- Department of Genetics and Genomics, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
- Department of Pediatrics, Tawam Hospital, Al Ain P.O. Box 15258, United Arab Emirates
| |
Collapse
|
2
|
Gil-Martínez J, Bernardo-Seisdedos G, Mato JM, Millet O. The use of pharmacological chaperones in rare diseases caused by reduced protein stability. Proteomics 2022; 22:e2200222. [PMID: 36205620 DOI: 10.1002/pmic.202200222] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/26/2022] [Accepted: 09/29/2022] [Indexed: 11/05/2022]
Abstract
Rare diseases are most often caused by inherited genetic disorders that, after translation, will result in a protein with altered function. Decreased protein stability is the most frequent mechanism associated with a congenital pathogenic missense mutation and it implies the destabilization of the folded conformation in favour of unfolded or misfolded states. In the cellular context and when experimental data is available, a mutant protein with altered thermodynamic stability often also results in impaired homeostasis, with the deleterious accumulation of protein aggregates, metabolites and/or metabolic by-products. In the last decades, a significant effort has enabled the characterization of rare diseases associated to protein stability defects and triggered the development of innovative therapeutic intervention lines, say, the use of pharmacological chaperones to correct the intracellular impaired homeostasis. Here, we review the current knowledge on rare diseases caused by reduced protein stability, paying special attention to the thermodynamic aspects of the protein destabilization, also focusing on some examples where pharmacological chaperones are being tested.
Collapse
Affiliation(s)
- Jon Gil-Martínez
- Precision Medicine and Metabolism Laboratory, CIC bioGUNE, Basque Research and Technology Alliance (BRTA), Bizkaia, Spain
| | | | - José M Mato
- Precision Medicine and Metabolism Laboratory, CIC bioGUNE, Basque Research and Technology Alliance (BRTA), Bizkaia, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
| | - Oscar Millet
- Precision Medicine and Metabolism Laboratory, CIC bioGUNE, Basque Research and Technology Alliance (BRTA), Bizkaia, Spain.,ATLAS Molecular Pharma, Bizkaia, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
| |
Collapse
|
3
|
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.
Collapse
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.
| |
Collapse
|
4
|
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.
Collapse
|
5
|
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: 7] [Impact Index Per Article: 3.5] [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.
Collapse
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
| |
Collapse
|
6
|
Waheed N, Fayyaz Z, Imran A. Spectrum of clinical manifestation of methylmalonic acidemia and homocystinuria in a family of six siblings: novel combination of transcobalamin receptor defect (CD320) and cblC deficiency (MMACHC). EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2021. [DOI: 10.1186/s43042-021-00197-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Methylmalonic acidemia with homocystinuria is caused by a rare inborn error of vitamin B12 (cobalamin) metabolism. There are four complementation classes of cobalamin defects cblC, cblD, cblF, and cblJ that are responsible for combined methylmalonic acidemia and homocystinuria.
Case presentation
We report a case of a Pakistani family composed of six children diagnosed with methylmalonic acidemia and homocystinuria (MMA + HCU). Mutation analysis of siblings revealed a variable combination of c.394C>T mutation in the MMACHC gene and c.262_264del in CD320 gene. All siblings had variable age of onset, initial symptomatology, the severity of disease, and response to treatment. The maximum age of presentation was 6.5 years and the minimum age was at birth. The spectrum of symptoms ranged from a subtle learning disability to global developmental delay within the same family. None of them had a seizure disorder, megaloblastic anemia, visual disturbance, and vascular events.CD320 defect itself is very rare, and only 12 cases have been reported so far. We report six cases, four of them had homozygous MMACHC variant c.394C>T and the other two had heterozygous MMACHC mutations in c.394C>T and c.262_264del in CD 320 genes. To date, neither such case has been reported in the literature or this compound heterozygous mutation.
Conclusion
Our case report emphasizes that the diagnosis of inherited metabolic disorder in a child obviates the need to screen all siblings for the same disorder.
Collapse
|
7
|
Wingert V, Mukherjee S, Esser AJ, Behringer S, Tanimowo S, Klenzendorf M, Derevenkov IA, Makarov SV, Jacobsen DW, Spiekerkoetter U, Hannibal L. Thiolatocobalamins repair the activity of pathogenic variants of the human cobalamin processing enzyme CblC. Biochimie 2020; 183:108-125. [PMID: 33190793 DOI: 10.1016/j.biochi.2020.10.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/08/2020] [Accepted: 10/19/2020] [Indexed: 01/08/2023]
Abstract
Thiolatocobalamins are a class of cobalamins comprised of naturally occurring and synthetic ligands. Glutathionylcobalamin (GSCbl) occurs naturally in mammalian cells, and also as an intermediate in the glutathione-dependent dealkylation of methylcobalamin (MeCbl) to form cob(I)alamin by pure recombinant CblC from C. elegans. Glutathione-driven deglutathionylation of GSCbl was demonstrated both in mammalian as well as in C. elegans CblC. Dethiolation is orders of magnitude faster than dealkylation of Co-C bonded cobalamins, which motivated us to investigate two synthetic thiolatocobalamins as substrates to repair the enzymatic activity of pathogenic CblC variants in humans. We report the synthesis and kinetic characterization of cysteaminylcobalamin (CyaCbl) and 2-mercaptopropionylglycinocobalamin (MpgCbl). Both CyaCbl and MpgCbl were obtained in high purity (90-95%) and yield (78-85%). UV-visible spectral properties agreed with those reported for other thiolatocobalamins with absorbance maxima observed at 372 nm and 532 nm. Both CyaCbl and MpgCbl bound to wild type human recombinant CblC inducing spectral blue-shifts characteristic of the respective base-on to base-off transitions. Addition of excess glutathione (GSH) resulted in rapid elimination of the β-ligand to give aquacobalamin (H2OCbl) as the reaction product under aerobic conditions. Further, CyaCbl and MpgCbl underwent spontaneous dethiolation thereby repairing the loss of activity of pathogenic variants of human CblC, namely R161G and R161Q. We posit that thiolatocobalamins could be exploited therapeutically for the treatment of inborn errors of metabolism that impair processing of dietary and supplemental cobalamin forms. While these disorders are targets for newborn screening in some countries, there is currently no effective treatment available to patients.
Collapse
Affiliation(s)
- Victoria Wingert
- 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
| | - Srijan Mukherjee
- 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
| | - Anna J Esser
- 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
| | - Sidney Behringer
- 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
| | - Segun Tanimowo
- 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
| | - Melissa Klenzendorf
- 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; Faculty of Biology, University of Freiburg Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Ilia A Derevenkov
- Department of Food Chemistry, Ivanovo State University of Chemistry and Technology, Ivanovo, Russian Federation
| | - Sergei V Makarov
- Department of Food Chemistry, Ivanovo State University of Chemistry and Technology, Ivanovo, Russian Federation
| | - Donald W Jacobsen
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, USA
| | - Ute Spiekerkoetter
- Department of General Pediatrics, Adolescent Medicine and Neonatology, Faculty of Medicine, Medical Center - University of Freiburg, 79106, Freiburg, Germany
| | - 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.
| |
Collapse
|
8
|
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.
Collapse
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
| |
Collapse
|
9
|
Bun JS, Slack MD, Schemenauer DE, Johnson RJ. Comparative analysis of the human serine hydrolase OVCA2 to the model serine hydrolase homolog FSH1 from S. cerevisiae. PLoS One 2020; 15:e0230166. [PMID: 32182256 PMCID: PMC7077851 DOI: 10.1371/journal.pone.0230166] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 02/20/2020] [Indexed: 11/22/2022] Open
Abstract
Over 100 metabolic serine hydrolases are present in humans with confirmed functions in metabolism, immune response, and neurotransmission. Among potentially clinically-relevant but uncharacterized human serine hydrolases is OVCA2, a serine hydrolase that has been linked with a variety of cancer-related processes. Herein, we developed a heterologous expression system for OVCA2 and determined the comprehensive substrate specificity of OVCA2 against two ester substrate libraries. Based on this analysis, OVCA2 was confirmed as a serine hydrolase with a strong preference for long-chain alkyl ester substrates (>10-carbons) and high selectivity against a variety of short, branched, and substituted esters. Substitutional analysis was used to identify the catalytic residues of OVCA2 with a Ser117-His206-Asp179 classic catalytic triad. Comparison of the substrate specificity of OVCA2 to the model homologue FSH1 from Saccharomyces cerevisiae illustrated the tighter substrate selectivity of OVCA2, but their overlapping substrate preference for extended straight-chain alkyl esters. Conformation of the overlapping biochemical properties of OVCA2 and FSH1 was used to model structural information about OVCA2. Together our analysis provides detailed substrate specificity information about a previously, uncharacterized human serine hydrolase and begins to define the biological properties of OVCA2.
Collapse
Affiliation(s)
- Jessica S. Bun
- Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, United States of America
| | - Michael D. Slack
- Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, United States of America
| | - Daniel E. Schemenauer
- Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, United States of America
| | - R. Jeremy Johnson
- Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, United States of America
- * E-mail:
| |
Collapse
|
10
|
Huemer M, Baumgartner MR. The clinical presentation of cobalamin-related disorders: From acquired deficiencies to inborn errors of absorption and intracellular pathways. J Inherit Metab Dis 2019; 42:686-705. [PMID: 30761552 DOI: 10.1002/jimd.12012] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Revised: 09/25/2018] [Accepted: 09/27/2018] [Indexed: 12/11/2022]
Abstract
This review gives an overview of clinical characteristics, treatment and outcome of nutritional and acquired cobalamin (Cbl; synonym: vitamin B12) deficiencies, inborn errors of Cbl absorption and intracellular trafficking, as well as methylenetetrahydrofolate dehydrogenase (MTHFD1) and methylene tetrahydrofolate reductase (MTHFR) deficiencies, which impair Cbl-dependent remethylation. Acquired and inborn Cbl-related disorders and MTHFR deficiency cause multisystem, often severe disease. Failure to thrive, neurocognitive or psychiatric symptoms, eye disease, bone marrow alterations, microangiopathy and thromboembolic events are characteristic. The recently identified MTHFD1 defect additionally presents with severe immune deficiency. Deficient Cbl-dependent enzymes cause reduced methylation capacity and metabolite toxicity. Further net-effects of perturbed Cbl function or reduced Cbl supply causing oxidative stress, altered cytokine regulation or immune functions are discussed.
Collapse
Affiliation(s)
- Martina Huemer
- Division of Metabolism and Children's Research Center, University Children's Hospital Zürich, Zürich, Switzerland
- Department of Paediatrics, Landeskrankenhaus Bregenz, Bregenz, Austria
| | - Matthias R Baumgartner
- Division of Metabolism and Children's Research Center, University Children's Hospital Zürich, Zürich, Switzerland
| |
Collapse
|
11
|
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.
Collapse
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
| |
Collapse
|
12
|
Wang SJ, Yan CZ, Wen B, Zhao YY. Clinical feature and outcome of late-onset cobalamin C disease patients with neuropsychiatric presentations: a Chinese case series. Neuropsychiatr Dis Treat 2019; 15:549-555. [PMID: 30863077 PMCID: PMC6391119 DOI: 10.2147/ndt.s196924] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
OBJECTIVE The Cobalamin C (cblC) disease is an inborn error of cobalamin metabolism. Late-onset cblC disease was diagnosed in patients having overt symptoms after 4 years of age. The late-onset cblC disease patients were rare and easily misdiagnosed. This study analyzed the clinical presentations, gene mutations, and treatments of Chinese patients with late-onset cblC disease. METHODS The clinical data of 26 Han Chinese patients diagnosed with late-onset cblC disease were retrospectively analyzed. All patients underwent serum homocysteine level exam, urine concentrations of organic acids measurement, neuroimaging scans, gene analysis, and treatments evaluations. RESULTS The mean age at disease onset and diagnosis was 17.8±7.0 years. The most frequent neuropsychiatric disturbances were lower limb weakness (50%), psychiatric disturbances (46.2%), and gait instability (42.3%). The mean methylmalonic acid level in urine was 107.4±56.6 μmol/L, and mean serum total homocysteine was 105.4±41.0 μmol/L. The most common abnormal radioimaging changes were observed in the spinal cord (88%) and brain (32%). Scoliosis was detected in 85.7% of patients. The methylmalonic aciduria and homocystinuria type C protein gene analysis showed that c.482G>A (57.7%) and c.609G>A (34.6%) mutations were the most frequent genotypes. After treatments with hydroxycobalamin, betaine, folic acid, L-carnitine, and compound vitamin B, the clinical features and biochemical parameters of patients with late-onset cblC disease were found to be alleviated. CONCLUSION In our late-onset cblC disease cases, lower limb weakness, psychiatric disturbances, and gait instability were the most frequent manifestations. Patients responded well to the drug treatments with hydrocobalamin and betaine. When juvenile or adult patients with hyperhomocysteinemia present with neurological symptoms, cblC disease needs to be considered.
Collapse
Affiliation(s)
- Sheng-Jun Wang
- Department of Neurology, Qilu Hospital, Shandong University, Jinan, China,
| | - Chuan-Zhu Yan
- Department of Neurology, Qilu Hospital, Shandong University, Jinan, China,
| | - Bing Wen
- Department of Neurology, Qilu Hospital, Shandong University, Jinan, China,
| | - Yu-Ying Zhao
- Department of Neurology, Qilu Hospital, Shandong University, Jinan, China,
| |
Collapse
|
13
|
Almannai M, Marom R, Divin K, Scaglia F, Sutton VR, Craigen WJ, Lee B, Burrage LC, Graham BH. Milder clinical and biochemical phenotypes associated with the c.482G>A (p.Arg161Gln) pathogenic variant in cobalamin C disease: Implications for management and screening. Mol Genet Metab 2017; 122:60-66. [PMID: 28693988 PMCID: PMC5612879 DOI: 10.1016/j.ymgme.2017.06.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 06/24/2017] [Accepted: 06/25/2017] [Indexed: 02/08/2023]
Abstract
INTRODUCTION Cobalamin C disease is a multisystemic disease with variable manifestations and age of onset. Genotype-phenotype correlations are well-recognized in this disorder. Here, we present a large cohort of individuals with cobalamin C disease, several of whom are heterozygous for the c.482G>A pathogenic variant (p.Arg161Gln). We compared clinical characteristics of individuals with this pathogenic variant to those who do not have this variant. To our knowledge, this study represents the largest single cohort of individuals with the c.482G>A (p.Arg161Gln) pathogenic variant. METHODS A retrospective chart review of 27 individuals from 21 families with cobalamin C disease who are followed at our facility was conducted. RESULTS 13 individuals (48%) are compound heterozygous with the c.482G>A (p.Arg161Gln) on one allele and a second pathogenic variant on the other allele. Individuals with the c.482G>A (p.Arg161Gln) pathogenic variant had later onset of symptoms and easier metabolic control. Moreover, they had milder biochemical abnormalities at presentation which likely contributed to the observation that 4 individuals (31%) in this group were missed by newborn screening. CONCLUSION The c.482G>A (p.Arg161Gln) pathogenic variant is associated with milder disease. These individuals may not receive a timely diagnosis as they may not be identified on newborn screening or because of unrecognized, late onset symptoms. Despite the milder presentation, significant complications can occur, especially if treatment is delayed.
Collapse
Affiliation(s)
- Mohammed Almannai
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Department of Molecular and Human Genetics, Texas Children's Hospital, Houston, TX, USA
| | - Ronit Marom
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Department of Molecular and Human Genetics, Texas Children's Hospital, Houston, TX, USA
| | - Kristian Divin
- Department of Molecular and Human Genetics, Texas Children's Hospital, Houston, TX, USA
| | - Fernando Scaglia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Department of Molecular and Human Genetics, Texas Children's Hospital, Houston, TX, USA
| | - V Reid Sutton
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Department of Molecular and Human Genetics, Texas Children's Hospital, Houston, TX, USA
| | - William J Craigen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Department of Molecular and Human Genetics, Texas Children's Hospital, Houston, TX, USA
| | - Brendan Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Department of Molecular and Human Genetics, Texas Children's Hospital, Houston, TX, USA
| | - Lindsay C Burrage
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Department of Molecular and Human Genetics, Texas Children's Hospital, Houston, TX, USA.
| | - Brett H Graham
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Department of Molecular and Human Genetics, Texas Children's Hospital, Houston, TX, USA.
| |
Collapse
|
14
|
Alvarez R, Casas J, López DJ, Ibarguren M, Suari-Rivera A, Terés S, Guardiola-Serrano F, Lossos A, Busquets X, Kakhlon O, Escribá PV. Triacylglycerol mimetics regulate membrane interactions of glycogen branching enzyme: implications for therapy. J Lipid Res 2017. [PMID: 28630259 DOI: 10.1194/jlr.m075531] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Adult polyglucosan body disease (APBD) is a neurological disorder characterized by adult-onset neurogenic bladder, spasticity, weakness, and sensory loss. The disease is caused by aberrant glycogen branching enzyme (GBE) (GBE1Y329S) yielding less branched, globular, and soluble glycogen, which tends to aggregate. We explore here whether, despite being a soluble enzyme, GBE1 activity is regulated by protein-membrane interactions. Because soluble proteins can contact a wide variety of cell membranes, we investigated the interactions of purified WT and GBE1Y329S proteins with different types of model membranes (liposomes). Interestingly, both triheptanoin and some triacylglycerol mimetics (TGMs) we have designed (TGM0 and TGM5) markedly enhance GBE1Y329S activity, possibly enough for reversing APBD symptoms. We show that the GBE1Y329S mutation exposes a hydrophobic amino acid stretch, which can either stabilize and enhance or alternatively, reduce the enzyme activity via alteration of protein-membrane interactions. Additionally, we found that WT, but not Y329S, GBE1 activity is modulated by Ca2+ and phosphatidylserine, probably associated with GBE1-mediated regulation of energy consumption and storage. The thermal stabilization and increase in GBE1Y329S activity induced by TGM5 and its omega-3 oil structure suggest that this molecule has a considerable therapeutic potential for treating APBD.
Collapse
Affiliation(s)
- Rafael Alvarez
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| | - Jesús Casas
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| | - David J López
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| | - Maitane Ibarguren
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| | - Ariadna Suari-Rivera
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| | - Silvia Terés
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| | - Francisca Guardiola-Serrano
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| | - Alexander Lossos
- Department of Neurology, Hadassah-Hebrew University Medical Center, E-91120 Jerusalem, Israel
| | - Xavier Busquets
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| | - Or Kakhlon
- Department of Neurology, Hadassah-Hebrew University Medical Center, E-91120 Jerusalem, Israel.
| | - Pablo V Escribá
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain.
| |
Collapse
|
15
|
Richard E, Brasil S, Leal F, Navarrete R, Vega A, Ecay MJ, Desviat LR, Pérez-Cerda C, Ugarte M, Merinero B, Pérez B. Isolated and Combined Remethylation Disorders. JOURNAL OF INBORN ERRORS OF METABOLISM AND SCREENING 2017. [DOI: 10.1177/2326409816685732] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Eva Richard
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO UAM-CSIC, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
- IdiPAZ, Madrid, Spain
| | - Sandra Brasil
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO UAM-CSIC, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
- IdiPAZ, Madrid, Spain
| | - Fátima Leal
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO UAM-CSIC, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
- IdiPAZ, Madrid, Spain
| | - Rosa Navarrete
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO UAM-CSIC, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
- IdiPAZ, Madrid, Spain
| | - Ana Vega
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO UAM-CSIC, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
- IdiPAZ, Madrid, Spain
| | - María Jesús Ecay
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO UAM-CSIC, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
- IdiPAZ, Madrid, Spain
| | - Lourdes R. Desviat
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO UAM-CSIC, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
- IdiPAZ, Madrid, Spain
| | - Celia Pérez-Cerda
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO UAM-CSIC, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
- IdiPAZ, Madrid, Spain
| | - Magdalena Ugarte
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO UAM-CSIC, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
- IdiPAZ, Madrid, Spain
| | - Begoña Merinero
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO UAM-CSIC, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
- IdiPAZ, Madrid, Spain
| | - Belén Pérez
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO UAM-CSIC, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
- IdiPAZ, Madrid, Spain
| |
Collapse
|
16
|
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: 169] [Impact Index Per Article: 24.1] [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.
Collapse
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.
| |
Collapse
|
17
|
The unusual substrate specificity of a virulence associated serine hydrolase from the highly toxic bacterium, Francisella tularensis. Biochem Biophys Rep 2016; 7:415-422. [PMID: 28955933 PMCID: PMC5613637 DOI: 10.1016/j.bbrep.2016.07.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 07/06/2016] [Accepted: 07/08/2016] [Indexed: 12/26/2022] Open
Abstract
Francisella tularensis is the causative agent of the highly, infectious disease, tularemia. Amongst the genes identified as essential to the virulence of F. tularensis was the proposed serine hydrolase FTT0941c. Herein, we purified FTT0941c to homogeneity and then characterized the folded stability, enzymatic activity, and substrate specificity of FTT0941c. Based on phylogenetic analysis, FTT0941c was classified within a divergent Francisella subbranch of the bacterial hormone sensitive lipase (HSL) superfamily, but with the conserved sequence motifs of a bacterial serine hydrolase. FTT0941c showed broad hydrolase activity against diverse libraries of ester substrates, including significant hydrolytic activity across alkyl ester substrates from 2 to 8 carbons in length. Among a diverse library of fluorogenic substrates, FTT0941c preferred α-cyclohexyl ester substrates, matching with the substrate specificity of structural homologues and the broad open architecture of its modeled binding pocket. By substitutional analysis, FTT0941c was confirmed to have a classic catalytic triad of Ser115, His278, and Asp248 and to remain thermally stable even after substitution. Its overall substrate specificity profile, divergent phylogenetic homology, and preliminary pathway analysis suggested potential biological functions for FTT0941c in diverse metabolic degradation pathways in F. tularensis. FTT0941c is an unstudied virulence associated hydrolase from F. tularensis (74). Classified as a bacterial HSL enzyme within a unique subclade of Francisella (85). Broad substrate specificity for alkyl, unsaturated, tertiary, and cyclic esters (79). Distinct substrate selectivity for α-cyclohexyl esters (54). Proposed metabolic role in cyclohexyl and benzoate ester hydrolysis pathways (76).
Collapse
|
18
|
Diez-Fernandez C, Wellauer O, Gemperle C, Rüfenacht V, Fingerhut R, Häberle J. Kinetic mutations in argininosuccinate synthetase deficiency: characterisation and in vitro correction by substrate supplementation. J Med Genet 2016; 53:710-9. [PMID: 27287393 DOI: 10.1136/jmedgenet-2016-103937] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 05/19/2016] [Indexed: 12/30/2022]
Abstract
BACKGROUND Citrullinemia type 1 is an autosomal-recessive urea cycle disorder caused by mutations in the ASS1 gene and characterised by increased plasma citrulline concentrations. Of the ∼90 argininosuccinate synthetase (ASS) missense mutations reported, 21 map near the substrate (aspartate or citrulline) binding site, and thus are potential kinetic mutations whose decreased activities could be amenable to substrate supplementation. This article aims at characterising these 21 ASS mutations to prove their disease-causing role and to test substrate supplementation as a novel therapeutic approach. METHODS We used an Escherichia coli expression system to study all potentially kinetic ASS mutations. All mutant enzymes were nickel-affinity purified, their activity and kinetic parameters were measured using tandem mass spectrometry and their thermal stability using differential scanning fluorimetry. Structural rationalisation of the effects of these mutations was performed. RESULTS Of the characterised mutants, 13 were totally inactive while 8 exhibited decreased affinity for aspartate and citrulline. The activity of these eight kinetic mutations could be rescued to ∼10-99% of the wild-type using high l-aspartate concentrations. CONCLUSIONS Substrate supplementation raised in vitro the activity of eight citrullinemia type 1 mutations with reduced affinity for aspartate. As a direct translation of these results to the clinics, we propose to further evaluate the use of oxaloacetate, a nitrogen-free aspartate precursor and already available medical food (anti-ageing and brain stimulating, not considered as a drug by the US Food and Drug Administration), in patients with citrullinemia type 1 with decreased aspartate affinity. Although only patients with kinetic mutations would benefit, oxaloacetate could offer a safe novel treatment.
Collapse
Affiliation(s)
- Carmen Diez-Fernandez
- Division of Metabolism, University Children's Hospital and Children's Research Center, Zurich, Switzerland
| | - Olivia Wellauer
- Division of Metabolism, University Children's Hospital and Children's Research Center, Zurich, Switzerland
| | - Corinne Gemperle
- Division of Metabolism, University Children's Hospital and Children's Research Center, Zurich, Switzerland
| | - Véronique Rüfenacht
- Division of Metabolism, University Children's Hospital and Children's Research Center, Zurich, Switzerland
| | - Ralph Fingerhut
- Neonatal Screening Laboratory, University Children's Hospital and Children's Research Center, Zurich, Switzerland
| | - Johannes Häberle
- Division of Metabolism, University Children's Hospital and Children's Research Center, Zurich, Switzerland
| |
Collapse
|
19
|
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.
Collapse
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
| |
Collapse
|
20
|
Forny P, Froese DS, Suormala T, Yue WW, Baumgartner MR. Functional characterization and categorization of missense mutations that cause methylmalonyl-CoA mutase (MUT) deficiency. Hum Mutat 2015; 35:1449-58. [PMID: 25125334 PMCID: PMC4441004 DOI: 10.1002/humu.22633] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 07/27/2014] [Indexed: 12/29/2022]
Abstract
Methylmalonyl-CoA mutase (MUT) is an essential enzyme in propionate catabolism that requires adenosylcobalamin as a cofactor. Almost 250 inherited mutations in the MUT gene are known to cause the devastating disorder methylmalonic aciduria; however, the mechanism of dysfunction of these mutations, more than half of which are missense changes, has not been thoroughly investigated. Here, we examined 23 patient missense mutations covering a spectrum of exonic/structural regions, clinical phenotypes, and ethnic populations in order to determine their influence on protein stability, using two recombinant expression systems and a thermostability assay, and enzymatic function by measuring MUT activity and affinity for its cofactor and substrate. Our data stratify MUT missense mutations into categories of biochemical defects, including (1) reduced protein level due to misfolding, (2) increased thermolability, (3) impaired enzyme activity, and (4) reduced cofactor response in substrate turnover. We further demonstrate the stabilization of wild-type and thermolabile mutants by chemical chaperones in vitro and in bacterial cells. This in-depth mutation study illustrates the tools available for MUT enzyme characterization, guides future categorization of further missense mutations, and supports the development of alternative, chaperone-based therapy for patients not responding to current treatment.
Collapse
Affiliation(s)
- Patrick Forny
- Division for Metabolic Disorders and Children's Research Center, University Children's Hospital, Zurich, Switzerland; Zurich Center for Integrative Human Physiology, University of Zurich, Switzerland
| | | | | | | | | |
Collapse
|
21
|
Gherasim C, Ruetz M, Li Z, Hudolin S, Banerjee R. Pathogenic mutations differentially affect the catalytic activities of the human B12-processing chaperone CblC and increase futile redox cycling. J Biol Chem 2015; 290:11393-402. [PMID: 25809485 DOI: 10.1074/jbc.m115.637132] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Indexed: 11/06/2022] Open
Abstract
Human CblC catalyzes the elimination of the upper axial ligand in cobalamin or B12 derivatives entering the cell from circulation. This processing step is critical for assimilation of dietary cobalamin into the active cofactor forms that support the B12-dependent enzymes, methionine synthase and methylmalonyl-CoA mutase. Using a modified nitroreductase scaffold tailored to bind cobalamin and glutathione, CblC exhibits versatility in the mechanism by which it removes cyano versus alkyl ligands in cobalamin. In this study, we have characterized the effects of two pathogenic missense mutations at the same residue, R161G and R161Q, which are associated with early and late onset of the CblC disorder, respectively. We find that the R161Q and R161G CblC mutants display lower protein stability and decreased dealkylation but not decyanation activity, suggesting that cyanocobalamin might be therapeutically useful for patients carrying mutations at Arg-161. The mutant proteins also exhibit impaired glutathione binding. In the presence of physiologically relevant glutathione concentrations, stabilization of the cob(II)alamin derivative is observed, which occurs at the expense of increased oxidation of glutathione. Futile redox cycling, which is suppressed in wild-type human CblC, explains the reported increase in oxidative stress levels associated with the CblC disorder.
Collapse
Affiliation(s)
- Carmen Gherasim
- From the Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600
| | - Markus Ruetz
- From the Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600
| | - Zhu Li
- From the Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600
| | - Stephanie Hudolin
- From the Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600
| | - Ruma Banerjee
- From the Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600
| |
Collapse
|
22
|
Rahmandar MH, Bawcom A, Romano ME, Hamid R. Cobalamin C deficiency in an adolescent with altered mental status and anorexia. Pediatrics 2014; 134:e1709-14. [PMID: 25367534 PMCID: PMC4533284 DOI: 10.1542/peds.2013-2711] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Although cobalamin (cbl) C deficiency is the most common inherited disorder of vitamin B12 metabolism, the late-onset form of the disease can be difficult to recognize because it has a broad phenotypic spectrum. In this report, we describe an adolescent female exposed to unknown illicit substances and sexual abuse who presented with psychosis, anorexia, seizures, and ataxia. The patient's diagnosis was delayed until a metabolic workup was initiated, revealing hyperhomocysteinemia, low normal plasma methionine, and methylmalonic aciduria. Ultimately, cblC deficiency was confirmed when molecular testing showed compound heterozygosity for mutations (c.271dupA and c.482G>A) in the MMACHC gene. This diagnosis led to appropriate treatment with hydroxocobalamin, betaine, and folate, which resulted in improvement of her clinical symptoms and laboratory values. This patient demonstrates a previously unrecognized presentation of late-onset cblC deficiency. Although neuropsychiatric symptoms are common in late-onset disease, seizures and cerebellar involvement are not. Furthermore, anorexia has not been previously described in these patients. This case emphasizes that inborn errors of metabolism should be part of the differential diagnosis for a teenager presenting with altered mental status, especially when the diagnosis is challenging or neurologic symptoms are unexplained. Correct diagnosis of this condition is important because treatment is available and can result in clinical improvement.(1.)
Collapse
Affiliation(s)
| | - Amanda Bawcom
- Division of Medical Genetics and Genomic Medicine, and
| | - Mary E. Romano
- Division of Adolescent and Young Adult Health, Department of Pediatrics, Monroe Carell Jr Children’s Hospital at Vanderbilt University, Nashville, Tennessee
| | - Rizwan Hamid
- Division of Medical Genetics and Genomic Medicine, and
| |
Collapse
|
23
|
Hu L, Diez-Fernandez C, Rüfenacht V, Hismi BÖ, Ünal Ö, Soyucen E, Çoker M, Bayraktar BT, Gunduz M, Kiykim E, Olgac A, Pérez-Tur J, Rubio V, Häberle J. Recurrence of carbamoyl phosphate synthetase 1 (CPS1) deficiency in Turkish patients: characterization of a founder mutation by use of recombinant CPS1 from insect cells expression. Mol Genet Metab 2014; 113:267-73. [PMID: 25410056 DOI: 10.1016/j.ymgme.2014.09.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 09/30/2014] [Accepted: 09/30/2014] [Indexed: 12/26/2022]
Abstract
Carbamoyl phosphate synthetase 1 (CPS1) deficiency due to CPS1 mutations is a rare autosomal-recessive urea cycle disorder causing hyperammonemia that can lead to death or severe neurological impairment. CPS1 catalyzes carbamoyl phosphate formation from ammonia, bicarbonate and two molecules of ATP, and requires the allosteric activator N-acetyl-L-glutamate. Clinical mutations occur in the entire CPS1 coding region, but mainly in single families, with little recurrence. We characterized here the only currently known recurrent CPS1 mutation, p.Val1013del, found in eleven unrelated patients of Turkish descent using recombinant His-tagged wild type or mutant CPS1 expressed in baculovirus/insect cell system. The global CPS1 reaction and the ATPase and ATP synthesis partial reactions that reflect, respectively, the bicarbonate and the carbamate phosphorylation steps, were assayed. We found that CPS1 wild type and V1013del mutant showed comparable expression levels and purity but the mutant CPS1 exhibited no significant residual activities. In the CPS1 structural model, V1013 belongs to a highly hydrophobic β-strand at the middle of the central β-sheet of the A subdomain of the carbamate phosphorylation domain and is close to the predicted carbamate tunnel that links both phosphorylation sites. Haplotype studies suggested that p.Val1013del is a founder mutation. In conclusion, the mutation p.V1013del inactivates CPS1 but does not render the enzyme grossly unstable or insoluble. Recurrence of this particular mutation in Turkish patients is likely due to a founder effect, which is consistent with the frequent consanguinity observed in the affected population.
Collapse
Affiliation(s)
- Liyan Hu
- Division of Metabolism, University Children's Hospital, 8032 Zurich, Switzerland; Children's Research Center, 8032 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, Switzerland
| | - Carmen Diez-Fernandez
- Division of Metabolism, University Children's Hospital, 8032 Zurich, Switzerland; Children's Research Center, 8032 Zurich, Switzerland; Instituto de Biomedicina de Valencia (IBV-CSIC), Valencia, Spain
| | - Véronique Rüfenacht
- Division of Metabolism, University Children's Hospital, 8032 Zurich, Switzerland; Children's Research Center, 8032 Zurich, Switzerland
| | - Burcu Öztürk Hismi
- Department of Pediatric Metabolic Diseases, Ihsan Dogramaci Children's Hospital, Hacettepe University, Ankara, Turkey; Gaziantep Children's Hospital, Gaziantep, Turkey
| | - Özlem Ünal
- Department of Pediatric Metabolic Diseases, Ihsan Dogramaci Children's Hospital, Hacettepe University, Ankara, Turkey; Erzurum Regional Training and Research Hospital, Erzurum, Turkey
| | - Erdogan Soyucen
- Department of Pediatric Metabolic Disease, Medical School, Akdeniz University, Antalya, Turkey
| | - Mahmut Çoker
- Department of Pediatric Metabolic Disease, Medical School, Ege University, Bornova, Izmir, Turkey
| | - Bilge Tanyeri Bayraktar
- Division of Neonatology, Department of Pediatrics, Bezmialem Vakif University, Istanbul, Turkey
| | - Mehmet Gunduz
- Ankara Cocuk Sagligi ve Hastaliklari, Cocuk Beslenme & Metabolizma Unitesi, Diskapi, Ankara, Turkey
| | - Ertugrul Kiykim
- Department of Pediatric Metabolic Diseases, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, Turkey
| | - Asburce Olgac
- Division of Metabolism and Nutrition, Gazi University Hospital, Ankara, Turkey
| | - Jordi Pérez-Tur
- Instituto de Biomedicina de Valencia (IBV-CSIC), Valencia, Spain; Centro de Investigación Biomédica en Red para Enfermedades Neurodegenerativas (CIBERNED-ISCIII), Valencia, Spain; Instituto de Investigación Sanitaria La Fe, Valencia, Spain
| | - Vicente Rubio
- Instituto de Biomedicina de Valencia (IBV-CSIC), Valencia, Spain; Group 739, Centro de Investigación Biomédica en Red para Enfermedades Raras (CIBERER-ISCIII), Valencia, Spain
| | - Johannes Häberle
- Division of Metabolism, University Children's Hospital, 8032 Zurich, Switzerland; Children's Research Center, 8032 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, Switzerland.
| |
Collapse
|
24
|
McCorvie TJ, Kopec J, Hyung SJ, Fitzpatrick F, Feng X, Termine D, Strain-Damerell C, Vollmar M, Fleming J, Janz JM, Bulawa C, Yue WW. Inter-domain communication of human cystathionine β-synthase: structural basis of S-adenosyl-L-methionine activation. J Biol Chem 2014; 289:36018-30. [PMID: 25336647 PMCID: PMC4276868 DOI: 10.1074/jbc.m114.610782] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Cystathionine β-synthase (CBS) is a key enzyme in sulfur metabolism, and its inherited deficiency causes homocystinuria. Mammalian CBS is modulated by the binding of S-adenosyl-l-methionine (AdoMet) to its regulatory domain, which activates its catalytic domain. To investigate the underlying mechanism, we performed x-ray crystallography, mutagenesis, and mass spectrometry (MS) on human CBS. The 1.7 Å structure of a AdoMet-bound CBS regulatory domain shows one AdoMet molecule per monomer, at the interface between two constituent modules (CBS-1, CBS-2). AdoMet binding is accompanied by a reorientation between the two modules, relative to the AdoMet-free basal state, to form interactions with AdoMet via residues verified by mutagenesis to be important for AdoMet binding (Phe443, Asp444, Gln445, and Asp538) and for AdoMet-driven inter-domain communication (Phe443, Asp538). The observed structural change is further supported by ion mobility MS, showing that as-purified CBS exists in two conformational populations, which converged to one in the presence of AdoMet. We therefore propose that AdoMet-induced conformational change alters the interface and arrangement between the catalytic and regulatory domains within the CBS oligomer, thereby increasing the accessibility of the enzyme active site for catalysis.
Collapse
Affiliation(s)
- Thomas J McCorvie
- From the Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Jolanta Kopec
- From the Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Suk-Joon Hyung
- Worldwide Research and Development, Pfizer Inc., Groton, Connecticut 06340, and
| | - Fiona Fitzpatrick
- From the Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Xidong Feng
- Worldwide Research and Development, Pfizer Inc., Groton, Connecticut 06340, and
| | - Daniel Termine
- the Pfizer Rare Disease Research Unit, Worldwide Research and Development, Pfizer Inc., Cambridge, Massachusetts 02140
| | - Claire Strain-Damerell
- From the Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Melanie Vollmar
- From the Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - James Fleming
- the Pfizer Rare Disease Research Unit, Worldwide Research and Development, Pfizer Inc., Cambridge, Massachusetts 02140
| | - Jay M Janz
- the Pfizer Rare Disease Research Unit, Worldwide Research and Development, Pfizer Inc., Cambridge, Massachusetts 02140
| | - Christine Bulawa
- the Pfizer Rare Disease Research Unit, Worldwide Research and Development, Pfizer Inc., Cambridge, Massachusetts 02140
| | - Wyatt W Yue
- From the Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ, United Kingdom,
| |
Collapse
|
25
|
Ciglia E, Vergin J, Reimann S, Smits SHJ, Schmitt L, Groth G, Gohlke H. Resolving hot spots in the C-terminal dimerization domain that determine the stability of the molecular chaperone Hsp90. PLoS One 2014; 9:e96031. [PMID: 24760083 PMCID: PMC3997499 DOI: 10.1371/journal.pone.0096031] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 04/02/2014] [Indexed: 12/24/2022] Open
Abstract
Human heat shock protein of 90 kDa (hHsp90) is a homodimer that has an essential role in facilitating malignant transformation at the molecular level. Inhibiting hHsp90 function is a validated approach for treating different types of tumors. Inhibiting the dimerization of hHsp90 via its C-terminal domain (CTD) should provide a novel way to therapeutically interfere with hHsp90 function. Here, we predicted hot spot residues that cluster in the CTD dimerization interface by a structural decomposition of the effective energy of binding computed by the MM-GBSA approach and confirmed these predictions using in silico alanine scanning with DrugScore(PPI). Mutation of these residues to alanine caused a significant decrease in the melting temperature according to differential scanning fluorimetry experiments, indicating a reduced stability of the mutant hHsp90 complexes. Size exclusion chromatography and multi-angle light scattering studies demonstrate that the reduced stability of the mutant hHsp90 correlates with a lower complex stoichiometry due to the disruption of the dimerization interface. These results suggest that the identified hot spot residues can be used as a pharmacophoric template for identifying and designing small-molecule inhibitors of hHsp90 dimerization.
Collapse
Affiliation(s)
- Emanuele Ciglia
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-University, Düsseldorf, Germany
| | - Janina Vergin
- Institute for Biochemical Plant Physiology, Heinrich-Heine-University, Düsseldorf, Germany
| | - Sven Reimann
- Institute of Biochemistry, Heinrich-Heine-University, Düsseldorf, Germany
| | - Sander H. J. Smits
- Institute of Biochemistry, Heinrich-Heine-University, Düsseldorf, Germany
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich-Heine-University, Düsseldorf, Germany
| | - Georg Groth
- Institute for Biochemical Plant Physiology, Heinrich-Heine-University, Düsseldorf, Germany
| | - Holger Gohlke
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-University, Düsseldorf, Germany
| |
Collapse
|
26
|
Moreno-Garcia MA, Rosenblatt DS, Jerome-Majewska LA. Vitamin B(12) metabolism during pregnancy and in embryonic mouse models. Nutrients 2013; 5:3531-50. [PMID: 24025485 PMCID: PMC3798919 DOI: 10.3390/nu5093531] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 08/10/2013] [Accepted: 08/23/2013] [Indexed: 11/16/2022] Open
Abstract
Vitamin B(12) (cobalamin, Cbl) is required for cellular metabolism. It is an essential coenzyme in mammals for two reactions: the conversion of homocysteine to methionine by the enzyme methionine synthase and the conversion of methylmalonyl-CoA to succinyl-CoA by the enzyme methylmalonyl-CoA mutase. Symptoms of Cbl deficiency are hematological, neurological and cognitive, including megaloblastic anaemia, tingling and numbness of the extremities, gait abnormalities, visual disturbances, memory loss and dementia. During pregnancy Cbl is essential, presumably because of its role in DNA synthesis and methionine synthesis; however, there are conflicting studies regarding an association between early pregnancy loss and Cbl deficiency. We here review the literature about the requirement for Cbl during pregnancy, and summarized what is known of the expression pattern and function of genes required for Cbl metabolism in embryonic mouse models.
Collapse
Affiliation(s)
- Maira A. Moreno-Garcia
- Department of Human Genetics, McGill University, 1205 Avenue Docteur Penfield, N5/13,Montreal, Quebec, Canada H3A 1B1; E-Mails: (M.A.M.-G.); (D.S.R.)
| | - David S. Rosenblatt
- Department of Human Genetics, McGill University, 1205 Avenue Docteur Penfield, N5/13,Montreal, Quebec, Canada H3A 1B1; E-Mails: (M.A.M.-G.); (D.S.R.)
- Department of Pediatrics, McGill University, Montreal, Quebec, Canada H3H 1P3
| | - Loydie A. Jerome-Majewska
- Department of Human Genetics, McGill University, 1205 Avenue Docteur Penfield, N5/13,Montreal, Quebec, Canada H3A 1B1; E-Mails: (M.A.M.-G.); (D.S.R.)
- Department of Pediatrics, McGill University, Montreal, Quebec, Canada H3H 1P3
- McGill University Health Centre, 4060 Ste. Catherine West, PT 420, Montreal, Quebec, Canada H3Z 2Z3
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-514-412-4400 (ext. 23279); Fax: +1-514-412-4331
| |
Collapse
|
27
|
Hannibal L, DiBello PM, Jacobsen DW. Proteomics of vitamin B12 processing. Clin Chem Lab Med 2013; 51:477-88. [PMID: 23241609 DOI: 10.1515/cclm-2012-0568] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 10/23/2012] [Indexed: 12/18/2022]
Abstract
The causes of cobalamin (B12, Cbl) deficiency are multifactorial. Whether nutritional due to poor dietary intake, or functional due to impairments in absorption or intracellular processing and trafficking events, the major symptoms of Cbl deficiency include megaloblastic anemia, neurological deterioration and in extreme cases, failure to thrive and death. The common biomarkers of Cbl deficiency (hyperhomocysteinemia and methylmalonic acidemia) are extremely valuable diagnostic indicators of the condition, but little is known about the changes that occur at the protein level. A mechanistic explanation bridging the physiological changes associated with functional B12 deficiency with its intracellular processers and carriers is lacking. In this article, we will cover the effects of B12 deficiency in a cblC-disrupted background (also referred to as MMACHC) as a model of functional Cbl deficiency. As will be shown, major protein changes involve the cytoskeleton, the neurological system as well as signaling and detoxification pathways. Supplementation of cultured MMACHC-mutant cells with hydroxocobalamin (HOCbl) failed to restore these variants to the normal phenotype, suggesting that a defective Cbl processing pathway produces irreversible changes at the protein level.
Collapse
Affiliation(s)
- Luciana Hannibal
- Department of Pathobiology (NC2 – 104), Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
| | | | | |
Collapse
|
28
|
Jeong J, Park J, Lee DY, Kim J. C-terminal truncation of a bovine B(12) trafficking chaperone enhances the sensitivity of the glutathione-regulated thermostability. BMB Rep 2013; 46:169-74. [PMID: 23527861 PMCID: PMC4133868 DOI: 10.5483/bmbrep.2013.46.3.158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human B12 trafficking chaperone hCblC is well conserved in mammals and non-mammalian eukaryotes. However, the C-terminal ∼40 amino acids of hCblC vary significantly and are predicted to be deleted by alternative splicing of the encoding gene. In this study, we examined the thermostability of the bovine CblC truncated at the C-terminal variable region (t-bCblC) and its regulation by glutathione. t-bCblC is highly thermolabile (Tm = ∼42℃) similar to the full-length protein (f-bCblC). However, t-bCblC is stabilized to a greater extent than f-bCblC by binding of reduced glutathione (GSH) with increased sensitivity to GSH. In addition, binding of oxidized glutathione (GSSG) destabilizes t-bCblC to a greater extent and with increased sensitivity as compared to f-bCblC. These results indicate that t-bCblC is a more sensitive form to be regulated by glutathione than the full-length form of the protein. [BMB Reports 2013; 46(3): 169-174]
Collapse
Affiliation(s)
- Jinju Jeong
- School of Biotechnology, Yeungnam University, Gyeongsan 712-749, Korea
| | | | | | | |
Collapse
|
29
|
Ellis EE, Adkins CT, Galovska NM, Lavis LD, Johnson RJ. Decoupled roles for the atypical, bifurcated binding pocket of the ybfF hydrolase. Chembiochem 2013; 14:1134-44. [PMID: 23670977 DOI: 10.1002/cbic.201300085] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Indexed: 11/08/2022]
Abstract
Serine hydrolases have diverse intracellular substrates, biological functions, and structural plasticity, and are thus important for biocatalyst design. Amongst serine hydrolases, the recently described ybfF enzyme family are promising novel biocatalysts with an unusual bifurcated substrate-binding cleft and the ability to recognize commercially relevant substrates. We characterized in detail the substrate selectivity of a novel ybfF enzyme from Vibrio cholerae (Vc-ybfF) by using a 21-member library of fluorogenic ester substrates. We assigned the roles of the two substrate-binding clefts in controlling the substrate selectivity and folded stability of Vc-ybfF by comprehensive substitution analysis. The overall substrate preference of Vc-ybfF was for short polar chains, but it retained significant activity with a range of cyclic and extended esters. This broad substrate specificity combined with the substitutional analysis demonstrates that the larger binding cleft controls the substrate specificity of Vc-ybfF. Key selectivity residues (Tyr116, Arg120, Tyr209) are also located at the larger binding pocket and control the substrate specificity profile. In the structure of ybfF the narrower binding cleft contains water molecules prepositioned for hydrolysis, but based on substitution this cleft showed only minimal contribution to catalysis. Instead, the residues surrounding the narrow binding cleft and at the entrance to the binding pocket contributed significantly to the folded stability of Vc-ybfF. The relative contributions of each cleft of the binding pocket to the catalytic activity and folded stability of Vc-ybfF provide a valuable map for designing future biocatalysts based on the ybfF scaffold.
Collapse
Affiliation(s)
- Elizabeth E Ellis
- Department of Chemistry, Butler University, 4600 Sunset Ave, Indianapolis, IN 46208-3443, USA
| | | | | | | | | |
Collapse
|
30
|
Jorge-Finnigan A, Brasil S, Underhaug J, Ruíz-Sala P, Merinero B, Banerjee R, Desviat LR, Ugarte M, Martinez A, Pérez B. Pharmacological chaperones as a potential therapeutic option in methylmalonic aciduria cblB type. Hum Mol Genet 2013; 22:3680-9. [PMID: 23674520 DOI: 10.1093/hmg/ddt217] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Methylmalonic aciduria (MMA) cblB type is caused by mutations in the MMAB gene. This encodes the enzyme ATP:cob(I)alamin adenosyltransferase (ATR), which converts reduced cob(I)alamin to an active adenosylcobalamin cofactor. We recently reported the presence of destabilizing pathogenic mutations that retain some residual ATR activity. The aim of the present study was to seek pharmacological chaperones as a tailored therapy for stabilizing the ATR protein. High-throughput ligand screening of over 2000 compounds was performed; six were found to enhance the thermal stability of purified recombinant ATR. Further studies using a well-established bacterial system in which the recombinant ATR protein was expressed in the presence of these six compounds, showed them all to increase the stability of the wild-type ATR and the p.Ile96Thr mutant proteins. Compound V (N-{[(4-chlorophenyl)carbamothioyl]amino}-2-phenylacetamide) significantly increased this stability and did not act as an inhibitor of the purified protein. Importantly, compound V increased the activity of ATR in patient-derived fibroblasts harboring the destabilizing p.Ile96Thr mutation in a hemizygous state to within control range. When cobalamin was coadministrated with compound V, mutant ATR activity further improved. Oral administration of low doses of compound V to C57BL/6J mice for 12 days, led to increase in steady-state levels of ATR protein in liver and brain (disease-relevant organs). These results hold promise for the clinical use of pharmacological chaperones in MMA cblB type patients harboring chaperone-responsive mutations.
Collapse
Affiliation(s)
- Ana Jorge-Finnigan
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO, UAM-CSIC, Universidad Autónoma de Madrid, Campus de Cantoblanco, Madrid, Spain
| | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Deme JC, Miousse IR, Plesa M, Kim JC, Hancock MA, Mah W, Rosenblatt DS, Coulton JW. Structural features of recombinant MMADHC isoforms and their interactions with MMACHC, proteins of mammalian vitamin B12 metabolism. Mol Genet Metab 2012; 107:352-62. [PMID: 22832074 DOI: 10.1016/j.ymgme.2012.07.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 07/01/2012] [Indexed: 12/17/2022]
Abstract
The genes MMACHC and MMADHC encode critical proteins involved in the intracellular metabolism of cobalamin. Two clinical features, homocystinuria and methylmalonic aciduria, define inborn errors of these genes. Based on disease phenotypes, MMADHC acts at a branch point for cobalamin delivery, apparently exerting its function through interaction with MMACHC that demonstrates dealkylase and decyanase activities. Here we present biophysical analyses of MMADHC to identify structural features and to further characterize its interaction with MMACHC. Two recombinant tag-less isoforms of MMADHC (MMADHCΔ1-12 and MMADHCΔ1-61) were expressed and purified. Full length MMACHC and full length MMADHC were detected in whole cell lysates of human cells; by Western blotting, their molecular masses corresponded to purified recombinant proteins. By clear-native PAGE and by dynamic light scattering, recombinant MMADHCs were stable and monodisperse. Both species were monomeric, adopting extended conformations in solution. Circular dichroism and secondary structure predictions correlated with significant regions of disorder within the N-terminal domain of MMADHC. We found no evidence that MMADHC binds cobalamin. Phage panning against MMADHC predicted four binding regions on MMACHC, two of which overlap with predicted sites on MMACHC at which it may self-associate. Specific, concentration-dependent responses were observed for MMACHC binding to itself and to both MMADHC constructs. As estimated in the sub-micromolar range, the binding of MMACHC to itself was weaker compared to its interaction with either of the MMADHC isoforms. We propose that the function of MMADHC is exerted through its structured C-terminal domain via interactions with MMACHC.
Collapse
Affiliation(s)
- Justin C Deme
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | | | | | | | | | | | | | | |
Collapse
|
32
|
Hedge MK, Gehring AM, Adkins CT, Weston LA, Lavis LD, Johnson RJ. The structural basis for the narrow substrate specificity of an acetyl esterase from Thermotoga maritima. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1824:1024-30. [DOI: 10.1016/j.bbapap.2012.05.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Revised: 05/09/2012] [Accepted: 05/22/2012] [Indexed: 10/28/2022]
|
33
|
Froese DS, Krojer T, Wu X, Shrestha R, Kiyani W, von Delft F, Gravel RA, Oppermann U, Yue WW. Structure of MMACHC Reveals an Arginine-Rich Pocket and a Domain-Swapped Dimer for Its B12 Processing Function. Biochemistry 2012; 51:5083-90. [DOI: 10.1021/bi300150y] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | - Xuchu Wu
- Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, Canada
| | | | | | | | - Roy A. Gravel
- Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, Canada
| | | | | |
Collapse
|
34
|
Destabilization of a bovine B₁₂ trafficking chaperone protein by oxidized form of glutathione. Biochem Biophys Res Commun 2012; 420:547-51. [PMID: 22446328 DOI: 10.1016/j.bbrc.2012.03.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Accepted: 03/06/2012] [Indexed: 11/20/2022]
Abstract
The protein, bCblCpro, is a bovine B(12) trafficking chaperone involved in intracellular B(12) metabolism. bCblCpro is highly thermolabile (T(m)=∼42°C) and the reduced form of glutathione, GSH, has been found to stabilize bCblCpro as a positive regulator. In this study, we discovered that the oxidized form of glutathione, GSSG, destabilizes bCblCpro, which is derived from changes in the conformation of the protein upon GSSG binding. The binding affinity for GSSG was determined to be similar with the affinity for GSH. The AC(50)=2.8 ± 0.4 mM of GSSG for destabilization of bCblCpro was consistently similar with the AC(50)=2.1 ± 0.5 mM of GSH for stabilization of the protein. These results suggest that GSSG is a negative regulator of bCblCpro and that the molar ratio of [GSH]/[GSSG] in cells may determine the stability of the B(12) trafficking chaperone.
Collapse
|
35
|
Zhang J, Topp EM. Protein G, protein A and protein A-derived peptides inhibit the agitation induced aggregation of IgG. Mol Pharm 2012; 9:622-8. [PMID: 22304418 DOI: 10.1021/mp200548x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Controlling and preventing aggregation is critical to the development of safe and effective antibody drug products. The studies presented here test the hypothesis that protein A and protein G inhibit the agitation-induced aggregation of IgG. The hypothesis is motivated by the enhanced conformational stability of proteins upon ligand binding and the specific binding affinity of protein A and protein G to the Fc region of IgG. The aggregation of mixed human IgG from pooled human plasma was induced by agitation alone or in the presence of (i) protein A, (ii) protein G or (iii) a library of 24 peptides derived from the IgG-binding domain of protein A. Aggregation was assessed by UV spectroscopy, SDS-PAGE, high performance size-exclusion chromatography (HP-SEC), dynamic light scattering (DLS) and fluorescence spectroscopy. Additional information on IgG-ligand interactions was obtained using differential scanning fluorimetry (DSF) and competitive binding studies. The results demonstrate that protein A provides near-complete inhibition of agitation-induced aggregation, while protein G and two peptides from the peptide library show partial inhibition. The findings indicate that the IgG protein A-binding site is involved in the agitation-induced aggregation of IgG, and suggest a dominant role of colloidal interactions.
Collapse
Affiliation(s)
- Jun Zhang
- Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, Indiana 47901, USA
| | | |
Collapse
|
36
|
Carrillo-Carrasco N, Chandler RJ, Venditti CP. Combined methylmalonic acidemia and homocystinuria, cblC type. I. Clinical presentations, diagnosis and management. J Inherit Metab Dis 2012; 35:91-102. [PMID: 21748409 PMCID: PMC4219318 DOI: 10.1007/s10545-011-9364-y] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Revised: 05/27/2011] [Accepted: 06/09/2011] [Indexed: 11/25/2022]
Abstract
Combined methylmalonic acidemia and homocystinuria, cblC type, is an inborn error of intracellular cobalamin metabolism with a wide spectrum of clinical manifestations that is stated to be the most common inherited disorder of cobalamin metabolism. This metabolic disease is caused by mutations in the MMACHC gene and results in impaired intracellular synthesis of adenosylcobalamin and methylcobalamin, cofactors for the methylmalonyl-CoA mutase and methionine synthase enzymes. Elevated methylmalonic acid and homocysteine with decreased methionine production are the biochemical hallmarks of this disorder. Awareness of the diverse clinical presentations associated with cblC disease is necessary to provide a timely diagnosis, to guide management of affected individuals and to establish a framework for the future treatment of individuals detected through expanded newborn screening. This article reviews the biochemistry, clinical presentations, genotype-phenotype correlations, diagnosis and management of cblC disease.
Collapse
Affiliation(s)
- Nuria Carrillo-Carrasco
- Organic Acid Research Section, Genetics and Molecular Biology Branch, National Human Genome Research Institute, National Institutes of Health, Building 49, Room 4A18, Bethesda, MD 20892, USA
| | - Randy J. Chandler
- Organic Acid Research Section, Genetics and Molecular Biology Branch, National Human Genome Research Institute, National Institutes of Health, Building 49, Room 4A18, Bethesda, MD 20892, USA
- Institute for Biomedical Sciences, The George Washington University, Washington, DC, USA
| | - Charles P. Venditti
- Organic Acid Research Section, Genetics and Molecular Biology Branch, National Human Genome Research Institute, National Institutes of Health, Building 49, Room 4A18, Bethesda, MD 20892, USA
| |
Collapse
|
37
|
Glutathione and Vitamin B12 Cooperate in Stabilization of a B12 Trafficking Chaperone Protein. Protein J 2011; 31:158-65. [DOI: 10.1007/s10930-011-9385-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
|
38
|
Senisterra G, Chau I, Vedadi M. Thermal denaturation assays in chemical biology. Assay Drug Dev Technol 2011; 10:128-36. [PMID: 22066913 DOI: 10.1089/adt.2011.0390] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Thermal denaturation-based methods are becoming increasingly used to characterize protein stability and interactions. Recent technical advances have made these methods more suitable for high throughput screening. Reasonable throughput and the ability to perform these screens using commonly used instruments, such as RT-PCR machines or simple plate readers equipped with heating devices, facilitate these experiments in almost any laboratory. Introducing an aggregation-based monitoring approach as well as alternative fluorophores has allowed the screening of a wider range of proteins, including membrane proteins, against large chemical libraries. Thermal denaturation-based methods are independent of protein function, which is especially useful for the identification of orphan protein function. Here, we review applications of thermal denaturation-based methods in characterizing protein stability and ligand binding, and also provide information on protocol modifications that may further increase throughput.
Collapse
|
39
|
Glutathione increases the binding affinity of a bovine B₁₂ trafficking chaperone bCblC for vitamin B₁₂. Biochem Biophys Res Commun 2011; 412:360-5. [PMID: 21821010 DOI: 10.1016/j.bbrc.2011.07.103] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 07/22/2011] [Indexed: 11/20/2022]
Abstract
Intracellular B(12) metabolism involves a B(12) trafficking chaperone CblC that is well conserved in mammals including human. The protein CblC is known to bind cyanocobalamin (CNCbl, vitamin B(12)) inducing the base-off transition and convert it into an intermediate that can be used in enzyme cofactor synthesis. The binding affinity of human CblC for CNCbl was determined to be K(d)=≈6-16 μM, which is relatively low considering sub-micromolar B(12) concentrations (0.03-0.7 μM) in normal cells. In the current study, we discovered that the base-off transition of CNCbl upon binding to bCblC, a bovine homolog of human CblC, is facilitated in the presence of reduced form of glutathione (GSH). In addition, GSH dramatically increases the binding affinity for CNCbl lowering the K(d) from 27.1 ± 0.2-0.24 ± 0.09 μM. The effect of GSH is due to conformational change of bCblC upon binding with GSH, which was indicated by limited proteolysis and urea-induced equilibrium denaturation of the protein. The results of this study suggest that GSH positively modulates bCblC by increasing the binding affinity for CNCbl, which would enhance functional efficiency of the protein.
Collapse
|
40
|
Grünert SC, Fowler B, Superti-Furga A, Sass JO, Schwab KO. Hyperpyrexia resulting in encephalopathy in a 14-month-old patient with cblC disease. Brain Dev 2011; 33:432-6. [PMID: 20926213 DOI: 10.1016/j.braindev.2010.07.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Revised: 06/22/2010] [Accepted: 07/30/2010] [Indexed: 10/19/2022]
Abstract
Cobalamin C (cblC) defect, the most common inborn error of cobalamin metabolism, is a multisystem disorder usually presenting with progressive neurological, haematological and ophthalmological signs. We report on a cblC patient diagnosed in the newborn age who developed nearly normal during the first year of life. During an upper respiratory tract infection with severe hyperpyrexia at the age of 14months he developed an acute encephalopathic crisis resulting in severe mental retardation and marked internal and external cerebral atrophy. Hyperacute encephalopathic crises have not been observed so far in patients with cblC defect. It remains unclear, if this association is incidental or if the underlying metabolic defect may have predisposed the brain tissue to hyperpyrexia-induced damage.
Collapse
|
41
|
Plesa M, Kim J, Paquette SG, Gagnon H, Ng-Thow-Hing C, Gibbs BF, Hancock MA, Rosenblatt DS, Coulton JW. Interaction between MMACHC and MMADHC, two human proteins participating in intracellular vitamin B₁₂ metabolism. Mol Genet Metab 2011; 102:139-48. [PMID: 21071249 DOI: 10.1016/j.ymgme.2010.10.011] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Revised: 10/15/2010] [Accepted: 10/15/2010] [Indexed: 11/22/2022]
Abstract
The identification of eight genes involved in inherited cobalamin (Cbl) disorders has provided insight into the complexity of the vitamin B₁₂ trafficking pathway. Detailed knowledge about the structure, interaction, and physiological functions for many of the gene products, including the MMACHC and MMADHC proteins, is lacking. Having cloned, expressed, and purified MMACHC in Escherichia coli, we demonstrated its monodispersity by dynamic light scattering and measured its hydrodynamic radius, either alone or in complex with each of four vitamin B₁₂ derivatives. Using solution-phase intrinsic fluorescence and label-free, real-time surface plasmon resonance (SPR), MMACHC bound cyanocobalamin and hydroxycobalamin with similar low micromolar affinities (K(D) 6.4 and 9.8 μM, respectively); adenosylcobalamin and methylcobalamin also shared similar binding affinities for MMACHC (K(D) 1.7 and 1.4 μM, respectively). To predict specific regions of interaction between MMACHC and the proposed partner protein MMADHC, MMACHC was subjected to phage display. Five putative MMACHC-binding sites were identified. Finally, MMADHC was confirmed as a binding partner for MMACHC both in vitro (SPR) and in vivo (bacterial two-hybrid system).
Collapse
Affiliation(s)
- Maria Plesa
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Abstract
Vitamin B12 (cobalamin, Cbl) is an essential nutrient in human metabolism. Genetic diseases of vitamin B12 utilisation constitute an important fraction of inherited newborn disease. Functionally, B12 is the cofactor for methionine synthase and methylmalonyl CoA mutase. To function as a cofactor, B12 must be metabolised through a complex pathway that modifies its structure and takes it through subcellular compartments of the cell. Through the study of inherited disorders of vitamin B12 utilisation, the genes for eight complementation groups have been identified, leading to the determination of the general structure of vitamin B12 processing and providing methods for carrier testing, prenatal diagnosis and approaches to treatment.
Collapse
|