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McFarlane NR, Gui J, Oláh J, Harvey JN. Gaseous inhibition of the transsulfuration pathway by cystathionine β-synthase. Phys Chem Chem Phys 2024. [PMID: 38832404 DOI: 10.1039/d4cp01321b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
The transsulfuration pathway plays a key role in mammals for maintaining the balance between cysteine and homocysteine, whose concentrations are critical in several biochemical processes. Human cystathionine β-synthase is a heme-containing, pyridoxal 5'-phosphate (PLP)-dependent enzyme found in this pathway. The heme group does not participate directly in catalysis, but has a regulatory function, whereby CO or NO binding inhibits the PLP-dependent reactions. In this study, we explore the detailed structural changes responsible for inhibition using quantum chemical calculations to validate the experimentally observed bonding patterns associated with heme CO and NO binding and molecular dynamics simulations to explore the medium-range structural changes triggered by gas binding and propagating to the PLP active site, which is more than 20 Å distant from the heme group. Our results support a previously proposed mechanical signaling model, whereby the cysteine decoordination associated with gas ligand binding leads to breaking of a hydrogen bond with an arginine residue on a neighbouring helix. In turn, this leads to a shift in position of the helix, and hence also of the PLP cofactor, ultimately disrupting a key hydrogen bond that stabilizes the PLP in its catalytically active form.
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Affiliation(s)
- Neil R McFarlane
- Department of Chemistry, KU Leuven, Celestijnenlaan 200f-box 2404, B-3001 Leuven, Belgium.
| | - Jiangli Gui
- Department of Chemistry, KU Leuven, Celestijnenlaan 200f-box 2404, B-3001 Leuven, Belgium.
| | - Julianna Oláh
- Department of Inorganic and Analytical Chemistry Budapest University of Technology and Economics H-1111 Budapest, Műegyeten rakpart 3, Hungary.
| | - Jeremy N Harvey
- Department of Chemistry, KU Leuven, Celestijnenlaan 200f-box 2404, B-3001 Leuven, Belgium.
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2
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Roman JV, Mascarenhas R, Ceric K, Ballou DP, Banerjee R. Disease-causing cystathionine β-synthase linker mutations impair allosteric regulation. J Biol Chem 2023; 299:105449. [PMID: 37949228 PMCID: PMC10746528 DOI: 10.1016/j.jbc.2023.105449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 10/27/2023] [Accepted: 10/30/2023] [Indexed: 11/12/2023] Open
Abstract
Cystathionine β-synthase (CBS) catalyzes the committing step in the transsulfuration pathway, which is important for clearing homocysteine and furnishing cysteine. The transsulfuration pathway also generates H2S, a signaling molecule. CBS is a modular protein with a heme and pyridoxal phosphate-binding catalytic core, which is separated by a linker region from the C-terminal regulatory domain that binds S-adenosylmethionine (AdoMet), an allosteric activator. Recent cryo-EM structures reveal that CBS exists in a fibrillar form and undergoes a dramatic architectural rearrangement between the basal and AdoMet-bound states. CBS is the single most common locus of mutations associated with homocystinuria, and, in this study, we have characterized three clinical variants (K384E/N and M391I), which reside in the linker region. The native fibrillar form is destabilized in the variants, and differences in their limited proteolytic fingerprints also reveal conformational alterations. The crystal structure of the truncated K384N variant, lacking the regulatory domain, reveals that the overall fold of the catalytic core is unperturbed. M391I CBS exhibits a modest (1.4-fold) decrease while the K384E/N variants exhibit a significant (∼8-fold) decrease in basal activity, which is either unresponsive to or inhibited by AdoMet. Pre-steady state kinetic analyses reveal that the K384E/N substitutions exhibit pleiotropic effects and that the differences between them are expressed in the second half reaction, that is, homocysteine binding and reaction with the aminoacrylate intermediate. Together, these studies point to an important role for the linker in stabilizing the higher-order oligomeric structure of CBS and enabling AdoMet-dependent regulation.
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Affiliation(s)
- Joseph V Roman
- Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Romila Mascarenhas
- Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Karanfil Ceric
- Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - David P Ballou
- Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Ruma Banerjee
- Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan, USA.
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3
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Rathod DC, Vaidya SM, Hopp MT, Kühl T, Imhof D. Shapes and Patterns of Heme-Binding Motifs in Mammalian Heme-Binding Proteins. Biomolecules 2023; 13:1031. [PMID: 37509066 PMCID: PMC10377097 DOI: 10.3390/biom13071031] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 06/16/2023] [Accepted: 06/20/2023] [Indexed: 07/30/2023] Open
Abstract
Heme is a double-edged sword. On the one hand, it has a pivotal role as a prosthetic group of hemoproteins in many biological processes ranging from oxygen transport and storage to miRNA processing. On the other hand, heme can transiently associate with proteins, thereby regulating biochemical pathways. During hemolysis, excess heme, which is released into the plasma, can bind to proteins and regulate their activity and function. The role of heme in these processes is under-investigated, with one problem being the lack of knowledge concerning recognition mechanisms for the initial association of heme with the target protein and the formation of the resulting complex. A specific heme-binding sequence motif is a prerequisite for such complex formation. Although numerous short signature sequences indicating a particular protein function are known, a comprehensive analysis of the heme-binding motifs (HBMs) which have been identified in proteins, concerning specific patterns and structural peculiarities, is missing. In this report, we focus on the evaluation of known mammalian heme-regulated proteins concerning specific recognition and structural patterns in their HBMs. The Cys-Pro dipeptide motifs are particularly emphasized because of their more frequent occurrence. This analysis presents a comparative insight into the sequence and structural anomalies observed during transient heme binding, and consequently, in the regulation of the relevant protein.
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Affiliation(s)
- Dhruv C Rathod
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, D-53121 Bonn, Germany
| | - Sonali M Vaidya
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, D-53121 Bonn, Germany
| | - Marie-T Hopp
- Department of Chemistry, Institute for Integrated Natural Sciences, University of Koblenz, D-56070 Koblenz, Germany
| | - Toni Kühl
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, D-53121 Bonn, Germany
| | - Diana Imhof
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, D-53121 Bonn, Germany
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4
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Cornwell A, Badiei A. From Gasotransmitter to Immunomodulator: The Emerging Role of Hydrogen Sulfide in Macrophage Biology. Antioxidants (Basel) 2023; 12:antiox12040935. [PMID: 37107310 PMCID: PMC10135606 DOI: 10.3390/antiox12040935] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/11/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
Hydrogen sulfide (H2S) has been increasingly recognized as a crucial inflammatory mediator in immune cells, particularly macrophages, due to its direct and indirect effects on cellular signaling, redox homeostasis, and energy metabolism. The intricate regulation of endogenous H2S production and metabolism involves the coordination of transsulfuration pathway (TSP) enzymes and sulfide oxidizing enzymes, with TSP's role at the intersection of the methionine pathway and glutathione synthesis reactions. Additionally, H2S oxidation mediated by sulfide quinone oxidoreductase (SQR) in mammalian cells may partially control cellular concentrations of this gasotransmitter to induce signaling. H2S is hypothesized to signal through the posttranslational modification known as persulfidation, with recent research highlighting the significance of reactive polysulfides, a derivative of sulfide metabolism. Overall, sulfides have been identified as having promising therapeutic potential to alleviate proinflammatory macrophage phenotypes, which are linked to the exacerbation of disease outcomes in various inflammatory conditions. H2S is now acknowledged to have a significant influence on cellular energy metabolism by affecting the redox environment, gene expression, and transcription factor activity, resulting in changes to both mitochondrial and cytosolic energy metabolism processes. This review covers recent discoveries pertaining to the involvement of H2S in macrophage cellular energy metabolism and redox regulation, and the potential implications for the inflammatory response of these cells in the broader framework of inflammatory diseases.
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Affiliation(s)
- Alex Cornwell
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - Alireza Badiei
- Department of Veterinary Medicine, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
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5
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Insights into Domain Organization and Regulatory Mechanism of Cystathionine Beta-Synthase from Toxoplasma gondii. Int J Mol Sci 2022; 23:ijms23158169. [PMID: 35897745 PMCID: PMC9331509 DOI: 10.3390/ijms23158169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 07/20/2022] [Accepted: 07/20/2022] [Indexed: 11/25/2022] Open
Abstract
Cystathionine beta-synthase (CBS) is a key regulator of homocysteine metabolism. Although eukaryotic CBS have a similar domain architecture with a catalytic core and a C-terminal Bateman module, their regulation varies widely across phyla. In human CBS (HsCBS), the C-terminus has an autoinhibitory effect by acting as a cap that avoids the entry of substrates into the catalytic site. The binding of the allosteric modulator AdoMet to this region alleviates this cap, allowing the protein to progress from a basal toward an activated state. The same activation is obtained by artificial removal or heat-denaturation of the Bateman module. Recently, we reported the crystal structure of CBS from Toxoplasma gondii (TgCBS) showing that the enzyme assembles into basket-like dimers similar to the basal conformers of HsCBS. These findings would suggest a similar lid function for the Bateman module which, as in HsCBS, should relax in the absence of the C-terminal module. However, herein we demonstrate that, in contrast with HsCBS, removal of the Bateman module in TgCBS through deletion mutagenesis, limited proteolysis, or thermal denaturation has no effects on its activity, oligomerization, and thermal stability. This opposite behavior we have now found in TgCBS provides evidence of a novel type of CBS regulation.
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6
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Therapy Follows Diagnosis: Old and New Approaches for the Treatment of Acute Porphyrias, What We Know and What We Should Know. Diagnostics (Basel) 2022; 12:diagnostics12071618. [PMID: 35885523 PMCID: PMC9325038 DOI: 10.3390/diagnostics12071618] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 06/29/2022] [Accepted: 06/30/2022] [Indexed: 12/18/2022] Open
Abstract
Heme, iron protoporphyrin IX, is one of life’s most central molecules. Hence, availability of the enzymatic machinery necessary for its synthesis is crucial for every cell. Consequently, inborn errors of porphyrin metabolism that compromise normal synthesis, namely the family of porphyrias, undermine normal cellular metabolism given that heme has functions in catalytic centers, signal transduction and functional regulation and its synthesis is fully integrated into the center of intermediary metabolism. Very often, diagnosis of porphyrias is difficult and therefore delayed. Therapy can be as complicated. Over the last 50 years, several strategies have been developed: because of its integration with other parts of intermediary metabolism, the infusion of glucose (glucose effect) was one of the first attempts to counterbalance the dysregulation of porphyrin synthesis in porphyrias. Since heme synthesis is impaired, infusional replacement of heme was the next important therapeutic step. Recently, siRNA technology has been introduced in order to downregulate 5-ALA-synthase 1, which contributes to the patho-physiology of these diseases. Moreover, other novel therapies using enzyme protein replacement, mRNA techniques or proteostasis regulators are being developed.
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7
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Bhatt A, Mukhopadhyaya A, Ali ME. α-Helix in Cystathionine β-Synthase Enzyme Acts as an Electron Reservoir. J Phys Chem B 2022; 126:4754-4760. [PMID: 35687358 DOI: 10.1021/acs.jpcb.2c01657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The modulation of electron density at the Pyridoxal 5'-phosphate (PLP) catalytic center, because of charge transfer across the α-helix/PLP interface, is the determining factor for the enzymatic activities in the human Cystathionine β-Synthase (hCBS) enzyme. Applying density functional theory calculations, in conjunction with the real space density analysis, we investigated the charge density delocalization across the entire heme-α-helix-PLP electron communication channels. The electron delocalization due to hydrogen bonds at the heme/α-helix and α-helix/PLP interfaces are found to be extended over a very long range, as a result of redistribution of electron densities of the cofactors. Moreover, the internal hydrogen bonds of α-helix that are crucial for its secondary structure also participate in the electron redistribution through the structured hydrogen-bond network. α-Helix is found to accumulate the electron density at the ground state from both of the cofactors and behaves as an electron reservoir for catalytic reaction at the electrophilic center of PLP.
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Affiliation(s)
- Aashish Bhatt
- Institute of Nano Science and Technology, Sector-81, Mohali, Punjab-140306, India
| | - Aritra Mukhopadhyaya
- Institute of Nano Science and Technology, Sector-81, Mohali, Punjab-140306, India
| | - Md Ehesan Ali
- Institute of Nano Science and Technology, Sector-81, Mohali, Punjab-140306, India
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8
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Tran JU, Brown BL. Structural Basis for Allostery in PLP-dependent Enzymes. Front Mol Biosci 2022; 9:884281. [PMID: 35547395 PMCID: PMC9081730 DOI: 10.3389/fmolb.2022.884281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 03/25/2022] [Indexed: 11/13/2022] Open
Abstract
Pyridoxal 5′-phosphate (PLP)-dependent enzymes are found ubiquitously in nature and are involved in a variety of biological pathways, from natural product synthesis to amino acid and glucose metabolism. The first structure of a PLP-dependent enzyme was reported over 40 years ago, and since that time, there is a steady wealth of structural and functional information revealed for a wide array of these enzymes. A functional mechanism that is gaining more appreciation due to its relevance in drug design is that of protein allostery, where binding of a protein or ligand at a distal site influences the structure, organization, and function at the active site. Here, we present a review of current structure-based mechanisms of allostery for select members of each PLP-dependent enzyme family. Knowledge of these mechanisms may have a larger potential for identifying key similarities and differences among enzyme families that can eventually be exploited for therapeutic development.
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Affiliation(s)
- Jenny U Tran
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Breann L Brown
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, United States.,Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN, United States
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9
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Sardh E, Harper P. RNAi therapy with givosiran significantly reduces attack rates in acute intermittent porphyria. J Intern Med 2022; 291:593-610. [PMID: 35067977 DOI: 10.1111/joim.13443] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Acute hepatic porphyria (AHP) is a group of inherited metabolic disorders that affect hepatic heme biosynthesis. They are associated with attacks of neurovisceral manifestations that can be life threatening and constitute what is considered an acute porphyria attack. Until recently, the sole specific treatment for acute porphyria attacks consisted of the intravenous administration of hemin. Although attacks are often sporadic, some patients develop recurrent acute attacks, with devastating effects on quality of life. Liver transplantation has historically been the sole curative treatment option. The clinical manifestations of AHP are attributed to the accumulation of the heme precursor 5-aminolevulinic acid (ALA) and porphobilinogen (PBG). Advances in molecular engineering have provided new therapeutic possibilities for modifying the heme synthetic pathway. We reviewed the background and current status of AHP treatment using liver-directed small interfering RNA targeting ALAS1. The therapeutic aim was to normalize the levels of ALAS1, which is highly upregulated during acute porphyria attacks. Givosiran is now an approved drug for use in adults and adolescents aged 12 years and older. The results of clinical trials have shown that givosiran treatment leads to a rapid and sustained reduction of ALAS1 mRNA, decreased heme precursor levels, and a decreased rate of acute attacks compared with placebo. The clinical trials (phases I, II, and III) were all randomized and placebo controlled. Many patients enrolled in the initial clinical trials have continued treatment in open label extension and extended/compassionate-use programs in countries where givosiran is not yet commercially available.
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Affiliation(s)
- Eliane Sardh
- Department of Molecular Medicine and Surgery, Centre for Inherited Metabolic Diseases, Porphyria Centre Sweden, Department of Endocrinology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Pauline Harper
- Department of Medical Biochemistry and Biophysics, Centre for inherited Metabolic Diseases, Porphyria Centre Sweden., Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
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10
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Daneshian L, Renggli I, Hanaway R, Offermann LR, Schlachter CR, Hernandez Arriaza R, Henry S, Prakash R, Wybouw N, Dermauw W, Shimizu LS, Van Leeuwen T, Makris TM, Grbic V, Grbic M, Chruszcz M. Structural and functional characterization of β-cyanoalanine synthase from Tetranychus urticae. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2022; 142:103722. [PMID: 35063675 DOI: 10.1016/j.ibmb.2022.103722] [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: 11/11/2021] [Revised: 01/12/2022] [Accepted: 01/14/2022] [Indexed: 06/14/2023]
Abstract
Tetranychus urticae is a polyphagous spider mite that can feed on more than 1100 plant species including cyanogenic plants. The herbivore genome contains a horizontally acquired gene tetur10g01570 (TuCAS) that was previously shown to participate in cyanide detoxification. To understand the structure and determine the function of TuCAS in T. urticae, crystal structures of the protein with lysine conjugated pyridoxal phosphate (PLP) were determined. These structures reveal extensive TuCAS homology with the β-substituted alanine synthase family, and they show that this enzyme utilizes a similar chemical mechanism involving a stable α-aminoacrylate intermediate in β-cyanoalanine and cysteine synthesis. We demonstrate that TuCAS is more efficient in the synthesis of β-cyanoalanine, which is a product of the detoxification reaction between cysteine and cyanide, than in the biosynthesis of cysteine. Also, the enzyme carries additional enzymatic activities that were not previously described. We show that TuCAS can detoxify cyanide using O-acetyl-L-serine as a substrate, leading to the direct formation of β-cyanoalanine. Moreover, it catalyzes the reaction between the TuCAS-bound α-aminoacrylate intermediate and aromatic compounds with a thiol group. In addition, we have tested several compounds as TuCAS inhibitors. Overall, this study identifies additional functions for TuCAS and provides new molecular insight into the xenobiotic metabolism of T. urticae.
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Affiliation(s)
- Leily Daneshian
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, 29208, USA
| | - Isabella Renggli
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, 29208, USA
| | - Ryan Hanaway
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, 29208, USA
| | - Lesa R Offermann
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, 29208, USA
| | - Caleb R Schlachter
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, 29208, USA
| | | | - Shannon Henry
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, 29208, USA
| | - Rahul Prakash
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, 29208, USA
| | - Nicky Wybouw
- Terrestrial Ecology Unit, Department of Biology, Ghent University, Ghent, 9000, Belgium
| | - Wannes Dermauw
- Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Plant Sciences Unit, Merelbeke, 9820, Belgium; Department of Plants and Crops, Ghent University, Ghent, 9000, Belgium
| | - Linda S Shimizu
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, 29208, USA
| | | | - Thomas M Makris
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, 29208, USA; Department of Molecular and Structural Biochemistry, NC State University, Raleigh, NC, 27607, USA
| | - Vojislava Grbic
- Department of Biology, Western University, London, Ontario, N6A 5B7, Canada
| | - Miodrag Grbic
- Department of Biology, Western University, London, Ontario, N6A 5B7, Canada; University of La Rioja, Logrono, Spain
| | - Maksymilian Chruszcz
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, 29208, USA.
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11
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Kruger WD. How to fix a broken protein: restoring function to mutant human cystathionine β-synthase. Hum Genet 2021; 141:1299-1308. [PMID: 34636997 DOI: 10.1007/s00439-021-02386-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/05/2021] [Indexed: 12/17/2022]
Abstract
Inborn errors of metabolism (IEM) comprise a large class of recessive genetic diseases involving disorders of cellular metabolism that tend to be caused by missense mutations in which a single incorrect amino acid is substituted in the polypeptide chain. Cystathionine beta-synthase (CBS) deficiency is an example of an IEM that causes large elevations of blood total homocysteine levels, resulting in phenotypes in several tissues. Current treatment strategies involve dietary restriction and vitamin therapy, but these are only partially effective and do not work in all patients. Over 85% of the described mutations in CBS-deficient patients are missense mutations in which the mutant protein fails to fold into an active conformation. The ability of CBS to achieve an active conformation is affected by a variety of intracellular protein networks including the chaperone system and the ubiquitin/proteasome system, collectively referred to as the proteostasis network. Proteostasis modulators are drugs that perturb various aspects of these networks. In this article, we will review the evidence that modulation of the intracellular protein folding environment can be used as a potential therapeutic strategy to treat CBS deficiency and discuss the pros and cons of such a strategy.
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Affiliation(s)
- Warren D Kruger
- Cancer Signaling and Epigenetics Program, Fox Chase Cancer Center, Philadelphia, PA, USA.
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12
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Vassiliou D, Sardh E. Homocysteine elevation in givosiran treatment: Suggested ALAS1 siRNA effect on cystathionine beta-synthase. J Intern Med 2021; 290:928-930. [PMID: 34184789 DOI: 10.1111/joim.13341] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Daphne Vassiliou
- Department of Endocrinology, Karolinska University Hospital, Solna, Sweden.,Department of Molecular Medicine and Surgery (MMK), Karolinska Institutet, Solna, Sweden.,Porphyria Centre Sweden, Centre for Inherited Metabolic Diseases (CMMS), Karolinska University Hospital, Solna, Sweden
| | - Eliane Sardh
- Department of Endocrinology, Karolinska University Hospital, Solna, Sweden.,Department of Molecular Medicine and Surgery (MMK), Karolinska Institutet, Solna, Sweden.,Porphyria Centre Sweden, Centre for Inherited Metabolic Diseases (CMMS), Karolinska University Hospital, Solna, Sweden
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13
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Wang T, Ashrafi A, Modareszadeh P, Deese AR, Chacon Castro MDC, Alemi PS, Zhang L. An Analysis of the Multifaceted Roles of Heme in the Pathogenesis of Cancer and Related Diseases. Cancers (Basel) 2021; 13:4142. [PMID: 34439295 PMCID: PMC8393563 DOI: 10.3390/cancers13164142] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 08/08/2021] [Accepted: 08/13/2021] [Indexed: 12/28/2022] Open
Abstract
Heme is an essential prosthetic group in proteins and enzymes involved in oxygen utilization and metabolism. Heme also plays versatile and fascinating roles in regulating fundamental biological processes, ranging from aerobic respiration to drug metabolism. Increasing experimental and epidemiological data have shown that altered heme homeostasis accelerates the development and progression of common diseases, including various cancers, diabetes, vascular diseases, and Alzheimer's disease. The effects of heme on the pathogenesis of these diseases may be mediated via its action on various cellular signaling and regulatory proteins, as well as its function in cellular bioenergetics, specifically, oxidative phosphorylation (OXPHOS). Elevated heme levels in cancer cells intensify OXPHOS, leading to higher ATP generation and fueling tumorigenic functions. In contrast, lowered heme levels in neurons may reduce OXPHOS, leading to defects in bioenergetics and causing neurological deficits. Further, heme has been shown to modulate the activities of diverse cellular proteins influencing disease pathogenesis. These include BTB and CNC homology 1 (BACH1), tumor suppressor P53 protein, progesterone receptor membrane component 1 protein (PGRMC1), cystathionine-β-synthase (CBS), soluble guanylate cyclase (sGC), and nitric oxide synthases (NOS). This review provides an in-depth analysis of heme function in influencing diverse molecular and cellular processes germane to disease pathogenesis and the modes by which heme modulates the activities of cellular proteins involved in the development of cancer and other common diseases.
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Affiliation(s)
| | | | | | | | | | | | - Li Zhang
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX 75080, USA; (T.W.); (A.A.); (P.M.); (A.R.D.); (M.D.C.C.C.); (P.S.A.)
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14
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Structural perspectives on H 2S homeostasis. Curr Opin Struct Biol 2021; 71:27-35. [PMID: 34214926 DOI: 10.1016/j.sbi.2021.05.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 05/05/2021] [Accepted: 05/23/2021] [Indexed: 11/21/2022]
Abstract
The enzymes involved in H2S homeostasis regulate its production from sulfur-containing amino acids and its oxidation to thiosulfate and sulfate. Two gatekeepers in this homeostatic circuit are cystathionine beta-synthase, which commits homocysteine to cysteine, and sulfide quinone oxidoreductase, which commits H2S to oxidation via a mitochondrial pathway. Inborn errors at either locus affect sulfur metabolism, increasing homocysteine-derived H2S synthesis in the case of CBS deficiency and reducing complex IV activity in the case of SQOR deficiency. In this review, we focus on structural perspectives on the reaction mechanisms and regulation of these two enzymes, which are key to understanding H2S homeostasis in health and its dysregulation and potential targeting in disease.
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15
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Structural insight into the unique conformation of cystathionine β-synthase from Toxoplasma gondii. Comput Struct Biotechnol J 2021; 19:3542-3555. [PMID: 34194677 PMCID: PMC8225704 DOI: 10.1016/j.csbj.2021.05.052] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 05/31/2021] [Accepted: 05/31/2021] [Indexed: 11/23/2022] Open
Abstract
Cysteine plays a major role in the redox homeostasis and antioxidative defense mechanisms of many parasites of the phylum Apicomplexa. Of relevance to human health is Toxoplasma gondii, the causative agent of toxoplasmosis. A major route of cysteine biosynthesis in this parasite is the reverse transsulfuration pathway involving two key enzymes cystathionine β-synthase (CBS) and cystathionine γ-lyase (CGL). CBS from T. gondii (TgCBS) catalyzes the pyridoxal-5́-phosphate-dependent condensation of homocysteine with either serine or O-acetylserine to produce cystathionine. The enzyme can perform alternative reactions that use homocysteine and cysteine as substrates leading to the endogenous biosynthesis of hydrogen sulfide, another key element in maintaining the intracellular redox equilibrium. In contrast with human CBS, TgCBS lacks the N-terminal heme binding domain and is not responsive to S-adenosylmethionine. Herein, we describe the structure of a TgCBS construct that lacks amino acid residues 466-491 and shows the same activity of the native protein. TgCBS Δ466-491 was determined alone and in complex with reaction intermediates. A complementary molecular dynamics analysis revealed a unique domain organization, similar to the pathogenic mutant D444N of human CBS. Our data provides one missing piece in the structural diversity of CBSs by revealing the so far unknown three-dimensional arrangement of the CBS-type of Apicomplexa. This domain distribution is also detected in yeast and bacteria like Pseudomonas aeruginosa. These results pave the way for understanding the mechanisms by which TgCBS regulates the intracellular redox of the parasite, and have far-reaching consequences for the functional understanding of CBSs with similar domain distribution.
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16
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Benchoam D, Cuevasanta E, Julió Plana L, Capece L, Banerjee R, Alvarez B. Heme-Thiolate Perturbation in Cystathionine β-Synthase by Mercury Compounds. ACS OMEGA 2021; 6:2192-2205. [PMID: 33521459 PMCID: PMC7841933 DOI: 10.1021/acsomega.0c05475] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 12/22/2020] [Indexed: 05/11/2023]
Abstract
Cystathionine β-synthase (CBS) is an enzyme involved in sulfur metabolism that catalyzes the pyridoxal phosphate-dependent condensation of homocysteine with serine or cysteine to form cystathionine and water or hydrogen sulfide (H2S), respectively. CBS possesses a b-type heme coordinated by histidine and cysteine. Fe(III)-CBS is inert toward exogenous ligands, while Fe(II)-CBS is reactive. Both Fe(III)- and Fe(II)-CBS are sensitive to mercury compounds. In this study, we describe the kinetics of the reactions with mercuric chloride (HgCl2) and p-chloromercuribenzoic acid. These reactions were multiphasic and resulted in five-coordinate CBS lacking thiolate ligation, with six-coordinate species as intermediates. Computational QM/MM studies supported the feasibility of formation of species in which the thiolate is proximal to both the iron ion and the mercury compound. The reactions of Fe(II)-CBS were faster than those of Fe(III)-CBS. The observed rate constants of the first phase increased hyperbolically with concentration of the mercury compounds, with limiting values of 0.3-0.4 s-1 for Fe(III)-CBS and 40 ± 4 s-1 for Fe(II)-CBS. The data were interpreted in terms of alternative models of conformational selection or induced fit. Exposure of Fe(III)-CBS to HgCl2 led to heme release and activity loss. Our study reveals the complexity of the interactions between mercury compounds and CBS.
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Affiliation(s)
- Dayana Benchoam
- Laboratorio
de Enzimología, Instituto de Química Biológica,
Facultad de Ciencias, Universidad de la
República, Montevideo, 11400 Uruguay
- Centro
de Investigaciones Biomédicas (CEINBIO), Universidad de la República, Montevideo, 11800 Uruguay
| | - Ernesto Cuevasanta
- Laboratorio
de Enzimología, Instituto de Química Biológica,
Facultad de Ciencias, Universidad de la
República, Montevideo, 11400 Uruguay
- Centro
de Investigaciones Biomédicas (CEINBIO), Universidad de la República, Montevideo, 11800 Uruguay
- Unidad
de Bioquímica Analítica, Centro de Investigaciones Nucleares,
Facultad de Ciencias, Universidad de la
República, Montevideo, 11400 Uruguay
| | - Laia Julió Plana
- Departamento
de Química Inorgánica, Analítica y Química
Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires/Instituto de Química
Física de los Materiales, Medio Ambiente y Energía (INQUIMAE-CONICET), C1428EGA Buenos
Aires, Argentina
| | - Luciana Capece
- Departamento
de Química Inorgánica, Analítica y Química
Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires/Instituto de Química
Física de los Materiales, Medio Ambiente y Energía (INQUIMAE-CONICET), C1428EGA Buenos
Aires, Argentina
| | - Ruma Banerjee
- Department
of Biological Chemistry, University of Michigan
Medical School, Ann Arbor, Michigan 48109, United States
| | - Beatriz Alvarez
- Laboratorio
de Enzimología, Instituto de Química Biológica,
Facultad de Ciencias, Universidad de la
República, Montevideo, 11400 Uruguay
- Centro
de Investigaciones Biomédicas (CEINBIO), Universidad de la República, Montevideo, 11800 Uruguay
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17
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Lv H, Xu J, Bo T, Wang W. Characterization of Cystathionine β-Synthase TtCbs1 and Cysteine Synthase TtCsa1 Involved in Cysteine Biosynthesis in Tetrahymena thermophila. J Eukaryot Microbiol 2020; 68:e12834. [PMID: 33190347 DOI: 10.1111/jeu.12834] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 10/21/2020] [Accepted: 11/07/2020] [Indexed: 12/19/2022]
Abstract
Cysteine is implicated in important biological processes. It is synthesized through two different pathways. Cystathionine β-synthase and cystathionine γ-lyase participate in the reverse transsulfuration pathway, while serine acetyltransferase and cysteine synthase function in the de novo pathway. Two evolutionarily related pyridoxal 5'-phosphate-dependent enzymes, cystathionine β-synthase TtCBS1 (TTHERM_00558300) and cysteine synthase TtCSA1 (TTHERM_00239430), were identified from a freshwater protozoan Tetrahymena thermophila. TtCbs1 contained the N-terminal heme binding domain, catalytic domain, and C-terminal regulatory domain, whereas TtCsa1 consisted of two α/β domains. The catalytic core of the two enzymes is similar. TtCBS1 and TtCSA1 showed high expression levels in the vegetative growth stage and decreased during the sexual developmental stage. TtCbs1 and TtCsa1 were localized in the cytoplasm throughout different developmental stages. His-TtCbs1 and His-TtCsa1 were expressed and purified in vitro. TtCbs1 catalyzed the canonical reaction with the highest velocity and possessed serine sulfhydrylase activity. TtCsa1 showed cysteine synthase activity with high Km for O-acetylserine and low Km for sulfide and also had serine sulfhydrylase activity toward serine. Both TtCbs1 and TtCsa1 catalyzed hydrogen sulfide producing. TtCBS1 knockdown and TtCSA1 knockout mutants affected cysteine and glutathione synthesis. TtCbs1 and TtCsa1 are involved in cysteine synthesis through two different pathways in T. thermophila.
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Affiliation(s)
- Hongrui Lv
- School of Life Science, Shanxi University, Taiyuan, 030006, China.,Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006, China
| | - Jing Xu
- School of Life Science, Shanxi University, Taiyuan, 030006, China.,Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006, China
| | - Tao Bo
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006, China
| | - Wei Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006, China
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18
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Rahman MA, Glasgow JN, Nadeem S, Reddy VP, Sevalkar RR, Lancaster JR, Steyn AJC. The Role of Host-Generated H 2S in Microbial Pathogenesis: New Perspectives on Tuberculosis. Front Cell Infect Microbiol 2020; 10:586923. [PMID: 33330130 PMCID: PMC7711268 DOI: 10.3389/fcimb.2020.586923] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 10/13/2020] [Indexed: 12/14/2022] Open
Abstract
For centuries, hydrogen sulfide (H2S) was considered primarily as a poisonous gas and environmental hazard. However, with the discovery of prokaryotic and eukaryotic enzymes for H2S production, breakdown, and utilization, H2S has emerged as an important signaling molecule in a wide range of physiological and pathological processes. Hence, H2S is considered a gasotransmitter along with nitric oxide (•NO) and carbon monoxide (CO). Surprisingly, despite having overlapping functions with •NO and CO, the role of host H2S in microbial pathogenesis is understudied and represents a gap in our knowledge. Given the numerous reports that followed the discovery of •NO and CO and their respective roles in microbial pathogenesis, we anticipate a rapid increase in studies that further define the importance of H2S in microbial pathogenesis, which may lead to new virulence paradigms. Therefore, this review provides an overview of sulfide chemistry, enzymatic production of H2S, and the importance of H2S in metabolism and immunity in response to microbial pathogens. We then describe our current understanding of the role of host-derived H2S in tuberculosis (TB) disease, including its influences on host immunity and bioenergetics, and on Mycobacterium tuberculosis (Mtb) growth and survival. Finally, this review discusses the utility of H2S-donor compounds, inhibitors of H2S-producing enzymes, and their potential clinical significance.
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Affiliation(s)
| | - Joel N Glasgow
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Sajid Nadeem
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Vineel P Reddy
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ritesh R Sevalkar
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jack R Lancaster
- Department of Pharmacology and Chemical Biology, Vascular Medicine Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Adrie J C Steyn
- Africa Health Research Institute, Durban, South Africa.,Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States.,Centers for AIDS Research and Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, United States
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19
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Conter C, Fruncillo S, Fernández-Rodríguez C, Martínez-Cruz LA, Dominici P, Astegno A. Cystathionine β-synthase is involved in cysteine biosynthesis and H 2S generation in Toxoplasma gondii. Sci Rep 2020; 10:14657. [PMID: 32887901 PMCID: PMC7474069 DOI: 10.1038/s41598-020-71469-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 08/11/2020] [Indexed: 11/09/2022] Open
Abstract
Cystathionine β-synthase (CBS) catalyzes the condensation of serine and homocysteine to water and cystathionine, which is then hydrolyzed to cysteine, α-ketobutyrate and ammonia by cystathionine γ-lyase (CGL) in the reverse transsulfuration pathway. The protozoan parasite Toxoplasma gondii, the causative agent of toxoplasmosis, includes both CBS and CGL enzymes. We have recently reported that the putative T. gondii CGL gene encodes a functional enzyme. Herein, we cloned and biochemically characterized cDNA encoding CBS from T. gondii (TgCBS), which represents a first example of protozoan CBS that does not bind heme but possesses two C-terminal CBS domains. We demonstrated that TgCBS can use both serine and O-acetylserine to produce cystathionine, converting these substrates to an aminoacrylate intermediate as part of a PLP-catalyzed β-replacement reaction. Besides a role in cysteine biosynthesis, TgCBS can also efficiently produce hydrogen sulfide, preferentially via condensation of cysteine and homocysteine. Unlike the human counterpart and similar to CBS enzymes from lower organisms, the TgCBS activity is not stimulated by S-adenosylmethionine. This study establishes the presence of an intact functional reverse transsulfuration pathway in T. gondii and demonstrates the crucial role of TgCBS in biogenesis of H2S.
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Affiliation(s)
- Carolina Conter
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Verona, Italy
| | - Silvia Fruncillo
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Verona, Italy.,Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Carmen Fernández-Rodríguez
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160, Derio, Spain
| | - Luis Alfonso Martínez-Cruz
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160, Derio, Spain
| | - Paola Dominici
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Verona, Italy
| | - Alessandra Astegno
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Verona, Italy.
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20
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Portillo F, Vázquez J, Pajares MA. Protein-protein interactions involving enzymes of the mammalian methionine and homocysteine metabolism. Biochimie 2020; 173:33-47. [DOI: 10.1016/j.biochi.2020.02.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 02/20/2020] [Indexed: 12/16/2022]
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21
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Bublil EM, Majtan T. Classical homocystinuria: From cystathionine beta-synthase deficiency to novel enzyme therapies. Biochimie 2020; 173:48-56. [DOI: 10.1016/j.biochi.2019.12.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 12/13/2019] [Indexed: 01/23/2023]
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22
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Zuhra K, Augsburger F, Majtan T, Szabo C. Cystathionine-β-Synthase: Molecular Regulation and Pharmacological Inhibition. Biomolecules 2020; 10:E697. [PMID: 32365821 PMCID: PMC7277093 DOI: 10.3390/biom10050697] [Citation(s) in RCA: 102] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 04/24/2020] [Accepted: 04/27/2020] [Indexed: 12/11/2022] Open
Abstract
Cystathionine-β-synthase (CBS), the first (and rate-limiting) enzyme in the transsulfuration pathway, is an important mammalian enzyme in health and disease. Its biochemical functions under physiological conditions include the metabolism of homocysteine (a cytotoxic molecule and cardiovascular risk factor) and the generation of hydrogen sulfide (H2S), a gaseous biological mediator with multiple regulatory roles in the vascular, nervous, and immune system. CBS is up-regulated in several diseases, including Down syndrome and many forms of cancer; in these conditions, the preclinical data indicate that inhibition or inactivation of CBS exerts beneficial effects. This article overviews the current information on the expression, tissue distribution, physiological roles, and biochemistry of CBS, followed by a comprehensive overview of direct and indirect approaches to inhibit the enzyme. Among the small-molecule CBS inhibitors, the review highlights the specificity and selectivity problems related to many of the commonly used "CBS inhibitors" (e.g., aminooxyacetic acid) and provides a comprehensive review of their pharmacological actions under physiological conditions and in various disease models.
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Affiliation(s)
- Karim Zuhra
- Chair of Pharmacology, Section of Medicine, University of Fribourg, 1702 Fribourg, Switzerland; (K.Z.); (F.A.)
| | - Fiona Augsburger
- Chair of Pharmacology, Section of Medicine, University of Fribourg, 1702 Fribourg, Switzerland; (K.Z.); (F.A.)
| | - Tomas Majtan
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA;
| | - Csaba Szabo
- Chair of Pharmacology, Section of Medicine, University of Fribourg, 1702 Fribourg, Switzerland; (K.Z.); (F.A.)
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23
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Devi S, Tarique KF, Ali MF, Abdul Rehman SA, Gourinath S. Identification and characterization of Helicobacter pylori O-acetylserine-dependent cystathionine β-synthase, a distinct member of the PLP-II family. Mol Microbiol 2019; 112:718-739. [PMID: 31132312 DOI: 10.1111/mmi.14315] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/22/2019] [Indexed: 02/02/2023]
Abstract
O-acetylserine sulfhydrylase (OASS) and cystathionine β-synthase (CBS) are members of the PLP-II family, and involved in L-cysteine production. OASS produces L-cysteine via a de novo pathway while CBS participates in the reverse transsulfuration pathway. O-acetylserine-dependent CBS (OCBS) was previously identified as a new member of the PLP-II family, which are predominantly seen in bacteria. The bacterium Helicobacter pylori possess only one OASS (hp0107) gene and we showed that the protein coded by this gene actually functions as an OCBS and utilizes L-homocysteine and O-acetylserine (OAS) to produce cystathionine. HpOCBS did not show CBS activity with the substrate L-serine and required OAS exclusively. The HpOCBS structure in complex with methionine showed a closed cleft state, explaining the initial mode of substrate binding. Sequence and structural analyses showed differences between the active sites of OCBS and CBS, and explain their different substrate preferences. We identified three hydrophobic residues near the active site of OCBS, corresponding to one serine and two tyrosine residues in CBSs. Mutational studies were performed on HpOCBS and Saccharomyces cerevisiae CBS. A ScCBS double mutant (Y158F/Y226V) did not display activity with L-serine, indicating indispensability of these polar residues for selecting substrate L-serine, however, did show activity with OAS.
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Affiliation(s)
- Suneeta Devi
- Structural Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Khaja Faisal Tarique
- Structural Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.,Public Health Research Institute, Rutgers, Newark, NJ, USA
| | - Mohammad Farhan Ali
- Structural Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Syed Arif Abdul Rehman
- Structural Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.,MRC Protein Phosphorylation & Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, UK
| | - Samudrala Gourinath
- Structural Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
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24
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Pajares MA, Pérez-Sala D. Mammalian Sulfur Amino Acid Metabolism: A Nexus Between Redox Regulation, Nutrition, Epigenetics, and Detoxification. Antioxid Redox Signal 2018; 29:408-452. [PMID: 29186975 DOI: 10.1089/ars.2017.7237] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
SIGNIFICANCE Transsulfuration allows conversion of methionine into cysteine using homocysteine (Hcy) as an intermediate. This pathway produces S-adenosylmethionine (AdoMet), a key metabolite for cell function, and provides 50% of the cysteine needed for hepatic glutathione synthesis. The route requires the intake of essential nutrients (e.g., methionine and vitamins) and is regulated by their availability. Transsulfuration presents multiple interconnections with epigenetics, adenosine triphosphate (ATP), and glutathione synthesis, polyol and pentose phosphate pathways, and detoxification that rely mostly in the exchange of substrates or products. Major hepatic diseases, rare diseases, and sensorineural disorders, among others that concur with oxidative stress, present impaired transsulfuration. Recent Advances: In contrast to the classical view, a nuclear branch of the pathway, potentiated under oxidative stress, is emerging. Several transsulfuration proteins regulate gene expression, suggesting moonlighting activities. In addition, abnormalities in Hcy metabolism link nutrition and hearing loss. CRITICAL ISSUES Knowledge about the crossregulation between pathways is mostly limited to the hepatic availability/removal of substrates and inhibitors. However, advances regarding protein-protein interactions involving oncogenes, identification of several post-translational modifications (PTMs), and putative moonlighting activities expand the potential impact of transsulfuration beyond methylations and Hcy. FUTURE DIRECTIONS Increasing the knowledge on transsulfuration outside the liver, understanding the protein-protein interaction networks involving these enzymes, the functional role of their PTMs, or the mechanisms controlling their nucleocytoplasmic shuttling may provide further insights into the pathophysiological implications of this pathway, allowing design of new therapeutic interventions. Antioxid. Redox Signal. 29, 408-452.
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Affiliation(s)
- María A Pajares
- 1 Department of Chemical and Physical Biology, Centro de Investigaciones Biológicas (CSIC) , Madrid, Spain .,2 Molecular Hepatology Group, Instituto de Investigación Sanitaria La Paz (IdiPAZ) , Madrid, Spain
| | - Dolores Pérez-Sala
- 1 Department of Chemical and Physical Biology, Centro de Investigaciones Biológicas (CSIC) , Madrid, Spain
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25
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Bao X, Wu J, Kim S, LoRusso P, Li J. Pharmacometabolomics Reveals Irinotecan Mechanism of Action in Cancer Patients. J Clin Pharmacol 2018; 59:20-34. [PMID: 30052267 DOI: 10.1002/jcph.1275] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 05/31/2018] [Indexed: 12/25/2022]
Abstract
The purpose of this study was to identify early circulating metabolite changes implicated in the mechanism of action of irinotecan, a DNA topoisomerase I inhibitor, in cancer patients. A liquid chromatography-tandem mass spectrometry-based targeted metabolomic platform capable of measuring 254 endogenous metabolites was applied to profile circulating metabolites in plasma samples collected pre- and post-irinotecan treatment from 13 cancer patients. To gain further mechanistic insights, metabolic profiling was also performed for the culture medium of human primary hepatocytes (HepatoCells) and 2 cancer cell lines on exposure to SN-38 (an active metabolite of irinotecan). Intracellular reactive oxygen species (ROS) was detected by dihydroethidium assay. Irinotecan induced a global metabolic change in patient plasma, as represented by elevations of circulating purine/pyrimidine nucleobases, acylcarnitines, and specific amino acid metabolites. The plasma metabolic signature was well replicated in HepatoCells medium on SN-38 exposure, whereas in cancer cell medium SN-38 induced accumulation of pyrimidine/purine nucleosides and nucleobases while having no impact on acylcarnitines and amino acid metabolites. SN-38 induced ROS in HepatoCells, but not in cancer cells. Distinct metabolite signatures of SN-38 exposure in HepatoCells medium and cancer cell medium revealed different mechanisms of drug action on hepatocytes and cancer cells. Elevations in circulating purine/pyrimidine nucleobases may stem from nucleotide degradation following irinotecan-induced DNA double-strand breaks. Accumulations of circulating acylcarnitines and specific amino acid metabolites may reflect, at least in part, irinotecan-induced mitochondrial dysfunction and oxidative stress in the liver. The plasma metabolic signature of irinotecan exposure provides early insights into irinotecan mechanism of action in patients.
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Affiliation(s)
- Xun Bao
- Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI, USA
| | - Jianmei Wu
- Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI, USA
| | - Seongho Kim
- Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI, USA
| | - Patricia LoRusso
- Yale Cancer Center, Yale University School of Medicine, New Haven, CT, USA
| | - Jing Li
- Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI, USA
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26
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Gupta S, Kelow S, Wang L, Andrake MD, Dunbrack RL, Kruger WD. Mouse modeling and structural analysis of the p.G307S mutation in human cystathionine β-synthase ( CBS) reveal effects on CBS activity but not stability. J Biol Chem 2018; 293:13921-13931. [PMID: 30030379 DOI: 10.1074/jbc.ra118.002164] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 07/18/2018] [Indexed: 11/06/2022] Open
Abstract
Mutations in the cystathionine β-synthase (CBS) gene are the cause of classical homocystinuria, the most common inborn error in sulfur metabolism. The p.G307S mutation is the most frequent cause of CBS deficiency in Ireland, which has the highest prevalence of CBS deficiency in Europe. Individuals homozygous for this mutation tend to be severely affected and are pyridoxine nonresponsive, but the molecular basis for the strong effects of this mutation is unclear. Here, we characterized a transgenic mouse model lacking endogenous Cbs and expressing human p.G307S CBS protein from a zinc-inducible metallothionein promoter (Tg-G307S Cbs-/-). Unlike mice expressing other mutant CBS alleles, the Tg-G307S transgene could not efficiently rescue neonatal lethality of Cbs-/- in a C57BL/6J background. In a C3H/HeJ background, zinc-induced Tg-G307S Cbs-/- mice expressed high levels of p.G307S CBS in the liver, and this protein variant forms multimers, similarly to mice expressing WT human CBS. However, the p.G307S enzyme had no detectable residual activity. Moreover, treating mice with proteasome inhibitors failed to significantly increase CBS-specific activity. These findings indicated that the G307S substitution likely affects catalytic function as opposed to causing a folding defect. Using molecular dynamics simulation techniques, we found that the G307S substitution likely impairs catalytic function by limiting the ability of the tyrosine at position 308 to assume the proper conformational state(s) required for the formation of the pyridoxal-cystathionine intermediate. These results indicate that the p.G307S CBS is stable but enzymatically inert and therefore unlikely to respond to chaperone-based therapy.
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Affiliation(s)
- Sapna Gupta
- From the Cancer Biology Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111 and
| | - Simon Kelow
- the Department of Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Liqun Wang
- From the Cancer Biology Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111 and
| | - Mark D Andrake
- From the Cancer Biology Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111 and
| | - Roland L Dunbrack
- From the Cancer Biology Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111 and
| | - Warren D Kruger
- From the Cancer Biology Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111 and
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27
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Tu Y, Kreinbring CA, Hill M, Liu C, Petsko GA, McCune CD, Berkowitz DB, Liu D, Ringe D. Crystal Structures of Cystathionine β-Synthase from Saccharomyces cerevisiae: One Enzymatic Step at a Time. Biochemistry 2018; 57:3134-3145. [PMID: 29630349 DOI: 10.1021/acs.biochem.8b00092] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Cystathionine β-synthase (CBS) is a key regulator of sulfur amino acid metabolism, taking homocysteine from the methionine cycle to the biosynthesis of cysteine via the trans-sulfuration pathway. CBS is also a predominant source of H2S biogenesis. Roles for CBS have been reported for neuronal death pursuant to cerebral ischemia, promoting ovarian tumor growth, and maintaining drug-resistant phenotype by controlling redox behavior and regulating mitochondrial bioenergetics. The trans-sulfuration pathway is well-conserved in eukaryotes, but the analogous enzymes have different enzymatic behavior in different organisms. CBSs from the higher organisms contain a heme in an N-terminal domain. Though the presence of the heme, whose functions in CBSs have yet to be elucidated, is biochemically interesting, it hampers UV-vis absorption spectroscopy investigations of pyridoxal 5'-phosphate (PLP) species. CBS from Saccharomyces cerevisiae (yCBS) naturally lacks the heme-containing N-terminal domain, which makes it an ideal model for spectroscopic studies of the enzymological reaction catalyzed and allows structural studies of the basic yCBS catalytic core (yCBS-cc). Here we present the crystal structure of yCBS-cc, solved to 1.5 Å. Crystal structures of yCBS-cc in complex with enzymatic reaction intermediates have been captured, providing a structural basis for residues involved in catalysis. Finally, the structure of the yCBS-cc cofactor complex generated by incubation with an inhibitor shows apparent off-pathway chemistry not normally seen with CBS.
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Affiliation(s)
- Yupeng Tu
- Department of Biochemistry , Brandeis University , Waltham , Massachusetts 02454 , United States
| | - Cheryl A Kreinbring
- Department of Biochemistry , Brandeis University , Waltham , Massachusetts 02454 , United States
| | - Megan Hill
- Department of Biology , Brandeis University , Waltham , Massachusetts 02454 , United States
| | - Cynthia Liu
- Department of Biochemistry , Brandeis University , Waltham , Massachusetts 02454 , United States
| | - Gregory A Petsko
- Department of Neurology and Neuroscience , Weill Cornell Medical College , New York , New York 10021 , United States
| | - Christopher D McCune
- Department of Biochemistry , University of Nebraska , Lincoln , Nebraska 68588 , United States
| | - David B Berkowitz
- Department of Biochemistry , University of Nebraska , Lincoln , Nebraska 68588 , United States
| | - Dali Liu
- Department of Chemistry and Biochemistry , Loyola University Chicago , Chicago , Illinois 60660 , United States
| | - Dagmar Ringe
- Department of Biochemistry , Brandeis University , Waltham , Massachusetts 02454 , United States.,Department of Chemistry , Brandeis University , Waltham , Massachusetts 02454 , United States.,Rosenstiel Basic Medical Sciences Research Center , Brandeis University , Waltham , Massachusetts 02454 , United States
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28
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Niu W, Wang J, Qian J, Wang M, Wu P, Chen F, Yan S. Allosteric control of human cystathionine β-synthase activity by a redox active disulfide bond. J Biol Chem 2018; 293:2523-2533. [PMID: 29298893 PMCID: PMC5818181 DOI: 10.1074/jbc.ra117.000103] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 12/27/2017] [Indexed: 01/10/2023] Open
Abstract
Cystathionine β-synthase (CBS) is the central enzyme in the trans-sulfuration pathway that converts homocysteine to cysteine. It is also one of the three major enzymes involved in the biogenesis of H2S. CBS is a complex protein with a modular three-domain architecture, the central domain of which contains a 272CXXC275 motif whose function has yet to be determined. In the present study, we demonstrated that the CXXC motif exists in oxidized and reduced states in the recombinant enzyme by mass spectroscopic analysis and a thiol labeling assay. The activity of reduced CBS is ∼2-3-fold greater than that of the oxidized enzyme, and substitution of either cysteine in CXXC motif leads to a loss of redox sensitivity. The Cys272-Cys275 disulfide bond in CBS has a midpoint potential of -314 mV at pH 7.4. Additionally, the CXXC motif also exists in oxidized and reduced states in HEK293 cells under oxidative and reductive conditions, and stressing these cells with DTT results in more reduced enzyme and a concomitant increase in H2S production in live HEK293 cells as determined using a H2S fluorescent probe. By contrast, incubation of cells with aminooxyacetic acid, an inhibitor of CBS and cystathionine γ-lyase, eliminated the increase of H2S production after the cells were exposed to DTT. These findings indicate that CBS is post-translationally regulated by a redox-active disulfide bond in the CXXC motif. The results also demonstrate that CBS-derived H2S production is increased in cells under reductive stress conditions.
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Affiliation(s)
- Weining Niu
- From the School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, China
| | - Jun Wang
- From the School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, China
| | - Jing Qian
- From the School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, China
| | - Mengying Wang
- From the School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, China
| | - Ping Wu
- From the School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, China
| | - Fei Chen
- From the School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, China
| | - Shasha Yan
- From the School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, China
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29
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Filipovic MR, Zivanovic J, Alvarez B, Banerjee R. Chemical Biology of H 2S Signaling through Persulfidation. Chem Rev 2018; 118:1253-1337. [PMID: 29112440 PMCID: PMC6029264 DOI: 10.1021/acs.chemrev.7b00205] [Citation(s) in RCA: 580] [Impact Index Per Article: 96.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Signaling by H2S is proposed to occur via persulfidation, a posttranslational modification of cysteine residues (RSH) to persulfides (RSSH). Persulfidation provides a framework for understanding the physiological and pharmacological effects of H2S. Due to the inherent instability of persulfides, their chemistry is understudied. In this review, we discuss the biologically relevant chemistry of H2S and the enzymatic routes for its production and oxidation. We cover the chemical biology of persulfides and the chemical probes for detecting them. We conclude by discussing the roles ascribed to protein persulfidation in cell signaling pathways.
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Affiliation(s)
- Milos R. Filipovic
- Univeristy of Bordeaux, IBGC, UMR 5095, F-33077 Bordeaux, France
- CNRS, IBGC, UMR 5095, F-33077 Bordeaux, France
| | - Jasmina Zivanovic
- Univeristy of Bordeaux, IBGC, UMR 5095, F-33077 Bordeaux, France
- CNRS, IBGC, UMR 5095, F-33077 Bordeaux, France
| | - Beatriz Alvarez
- Laboratorio de Enzimología, Facultad de Ciencias and Center for Free Radical and Biomedical Research, Universidad de la Republica, 11400 Montevideo, Uruguay
| | - Ruma Banerjee
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109-0600, United States
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30
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Majtan T, Pey AL, Gimenez-Mascarell P, Martínez-Cruz LA, Szabo C, Kožich V, Kraus JP. Potential Pharmacological Chaperones for Cystathionine Beta-Synthase-Deficient Homocystinuria. Handb Exp Pharmacol 2018; 245:345-383. [PMID: 29119254 DOI: 10.1007/164_2017_72] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Classical homocystinuria (HCU) is the most common loss-of-function inborn error of sulfur amino acid metabolism. HCU is caused by a deficiency in enzymatic degradation of homocysteine, a toxic intermediate of methionine transformation to cysteine, chiefly due to missense mutations in the cystathionine beta-synthase (CBS) gene. As with many other inherited disorders, the pathogenic mutations do not target key catalytic residues, but rather introduce structural perturbations leading to an enhanced tendency of the mutant CBS to misfold and either to form nonfunctional aggregates or to undergo proteasome-dependent degradation. Correction of CBS misfolding would represent an alternative therapeutic approach for HCU. In this review, we summarize the complex nature of CBS, its multi-domain architecture, the interplay between the three cofactors required for CBS function [heme, pyridoxal-5'-phosphate (PLP), and S-adenosylmethionine (SAM)], as well as the intricate allosteric regulatory mechanism only recently understood, thanks to advances in CBS crystallography. While roughly half of the patients respond to treatment with a PLP precursor pyridoxine, many studies suggested usefulness of small chemicals, such as chemical and pharmacological chaperones or proteasome inhibitors, rescuing mutant CBS activity in cellular and animal models of HCU. Non-specific chemical chaperones and proteasome inhibitors assist in mutant CBS folding process and/or prevent its rapid degradation, thus resulting in increased steady-state levels of the enzyme and CBS activity. Recent interest in the field and available structural information will hopefully yield CBS-specific compounds, by using high-throughput screening and computational modeling of novel ligands, improving folding, stability, and activity of CBS mutants.
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Affiliation(s)
- Tomas Majtan
- Department of Pediatrics, School of Medicine, University of Colorado, Aurora, CO, USA.
| | - Angel L Pey
- Department of Physical Chemistry, University of Granada, Granada, Spain
| | - Paula Gimenez-Mascarell
- Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC bioGUNE), Technology Park of Bizkaia, Derio, Spain
| | - Luis Alfonso Martínez-Cruz
- Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC bioGUNE), Technology Park of Bizkaia, Derio, Spain
| | - Csaba Szabo
- Department of Anesthesiology, University of Texas Medical Branch, Galveston, TX, USA
| | - Viktor Kožich
- Department of Pediatrics and Adolescent Medicine, Charles University-First Faculty of Medicine and General University Hospital in Prague, Prague 2, Czech Republic
| | - Jan P Kraus
- Department of Pediatrics, School of Medicine, University of Colorado, Aurora, CO, USA
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31
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Giménez-Mascarell P, Majtan T, Oyenarte I, Ereño-Orbea J, Majtan J, Klaudiny J, Kraus JP, Martínez-Cruz LA. Crystal structure of cystathionine β-synthase from honeybee Apis mellifera. J Struct Biol 2017; 202:82-93. [PMID: 29275181 DOI: 10.1016/j.jsb.2017.12.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 11/28/2017] [Accepted: 12/19/2017] [Indexed: 11/26/2022]
Abstract
Cystathionine β-synthase (CBS), the key enzyme in the transsulfuration pathway, links methionine metabolism to the biosynthesis of cellular redox controlling molecules. CBS catalyzes the pyridoxal-5'-phosphate-dependent condensation of serine and homocysteine to form cystathionine, which is subsequently converted into cysteine. Besides maintaining cellular sulfur amino acid homeostasis, CBS also catalyzes multiple hydrogen sulfide-generating reactions using cysteine and homocysteine as substrates. In mammals, CBS is activated by S-adenosylmethionine (AdoMet), where it can adopt two different conformations (basal and activated), but exists as a unique highly active species in fruit fly Drosophila melanogaster. Here we present the crystal structure of CBS from honeybey Apis mellifera, which shows a constitutively active dimeric species and let explain why the enzyme is not allosterically regulated by AdoMet. In addition, comparison of available CBS structures unveils a substrate-induced closure of the catalytic cavity, which in humans is affected by the AdoMet-dependent regulation and likely impaired by the homocystinuria causing mutation T191M.
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Affiliation(s)
- Paula Giménez-Mascarell
- Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC Biogune), Technology Park of Bizkaia, 48160 Derio, Bizkaia, Spain
| | - Tomas Majtan
- Department of Pediatrics, School of Medicine, University of Colorado, Aurora, CO 80045, USA
| | - Iker Oyenarte
- Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC Biogune), Technology Park of Bizkaia, 48160 Derio, Bizkaia, Spain
| | - June Ereño-Orbea
- Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC Biogune), Technology Park of Bizkaia, 48160 Derio, Bizkaia, Spain
| | - Juraj Majtan
- Laboratory of Apidology and Apitherapy, Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava 84551, Slovakia
| | - Jaroslav Klaudiny
- Department of Glycobiology, Institute of Chemistry, Slovak Academy of Sciences, Bratislava 84538, Slovakia
| | - Jan P Kraus
- Department of Pediatrics, School of Medicine, University of Colorado, Aurora, CO 80045, USA
| | - Luis Alfonso Martínez-Cruz
- Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC Biogune), Technology Park of Bizkaia, 48160 Derio, Bizkaia, Spain.
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32
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Devi S, Abdul Rehman SA, Tarique KF, Gourinath S. Structural characterization and functional analysis of cystathionine β-synthase: an enzyme involved in the reverse transsulfuration pathway of Bacillus anthracis. FEBS J 2017; 284:3862-3880. [PMID: 28921884 DOI: 10.1111/febs.14273] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 08/31/2017] [Accepted: 09/13/2017] [Indexed: 01/29/2023]
Abstract
The reverse transsulfuration pathway has been reported to produce cysteine from homocysteine in eukaryotes ranging from protozoans to mammals while bacteria and plants produce cysteine via a de novo pathway. Interestingly, the bacterium Bacillus anthracis includes enzymes of the reverse transsulfuration pathway viz. cystathionine β-synthase [BaCBS, previously annotated to be an O-acetylserine sulfhydrylase (OASS)] and cystathionine γ-lyase. Here, we report the structure of BaCBS at a resolution of 2.2 Å. The enzyme was found to show CBS activity only with activated serine (O-acetylserine) and not with serine, and was also observed to display OASS activity but not serine sulfhydrylase activity. BaCBS was also found to produce hydrogen sulfide (H2 S) upon reaction of cysteine and homocysteine. A mutational study revealed Glu 220, conserved in CBS, to be necessary for generating H2 S. Structurally, BaCBS display a considerably more open active site than has been found for any other CBS or OASS, which was attributed to the presence of a helix at the junction of the C- and N-terminal domains. The root-mean-square deviation (RMSD) between the backbone Cα carbon atoms of BaCBS and those of other CBSs and OASSs were calculated to be greater than 3.0 Å. The pyridoxal 5'-phosphate at the active site was not traced, and appeared to be highly flexible due to the active site being wide open. Phylogenetic analysis revealed the presence of an O-acetylserine-dependent CBS in the bacterial domain and making separate clade from CBS and OASS indicating its evolution for specific function. DATABASE Structural data are available in the PDB under the accession number 5XW3.
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Affiliation(s)
- Suneeta Devi
- Structural Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Syed A Abdul Rehman
- Structural Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.,MRC Protein Phosphorylation & Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, UK
| | - Khaja F Tarique
- Structural Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.,Public Health Research Institute, Rutgers, Newark, NJ, USA
| | - Samudrala Gourinath
- Structural Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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33
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Majtan T, Park I, Carrillo RS, Bublil EM, Kraus JP. Engineering and Characterization of an Enzyme Replacement Therapy for Classical Homocystinuria. Biomacromolecules 2017; 18:1747-1761. [DOI: 10.1021/acs.biomac.7b00154] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Tomas Majtan
- Department
of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado 80045, United States
| | - Insun Park
- Department
of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado 80045, United States
| | - Richard S. Carrillo
- Department
of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado 80045, United States
| | - Erez M. Bublil
- Orphan
Technologies Ltd., Rapperswil, CH-8640, Switzerland
| | - Jan P. Kraus
- Department
of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado 80045, United States
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34
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Catalytic promiscuity and heme-dependent redox regulation of H 2S synthesis. Curr Opin Chem Biol 2017; 37:115-121. [PMID: 28282633 DOI: 10.1016/j.cbpa.2017.02.021] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 02/19/2017] [Accepted: 02/20/2017] [Indexed: 02/06/2023]
Abstract
The view of enzymes as punctilious catalysts has been shifting as examples of their promiscuous behavior increase. However, unlike a number of cases where the physiological relevance of breached substrate specificity is questionable, the very synthesis of H2S relies on substrate and reaction promiscuity, which presents the enzymes with a multitude of substrate and reaction choices. The transsulfuration pathway, a major source of H2S, is inherently substrate-ambiguous. A heme-regulated switch embedded in the first enzyme in the pathway can help avert the stochastic production of cysteine versus H2S and control switching between metabolic tracks to meet cellular needs. This review discusses the dominant role of enzyme promiscuity in pathways that double as sulfur catabolic and H2S synthetic tracks.
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35
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McCune C, Chan SJ, Beio ML, Shen W, Chung WJ, Szczesniak LM, Chai C, Koh SQ, Wong PTH, Berkowitz DB. "Zipped Synthesis" by Cross-Metathesis Provides a Cystathionine β-Synthase Inhibitor that Attenuates Cellular H2S Levels and Reduces Neuronal Infarction in a Rat Ischemic Stroke Model. ACS CENTRAL SCIENCE 2016; 2:242-52. [PMID: 27163055 PMCID: PMC4850510 DOI: 10.1021/acscentsci.6b00019] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Indexed: 05/08/2023]
Abstract
The gaseous neuromodulator H2S is associated with neuronal cell death pursuant to cerebral ischemia. As cystathionine β-synthase (CBS) is the primary mediator of H2S biogenesis in the brain, it has emerged as a potential target for the treatment of stroke. Herein, a "zipped" approach by alkene cross-metathesis into CBS inhibitor candidate synthesis is demonstrated. The inhibitors are modeled after the pseudo-C 2-symmetric CBS product (l,l)-cystathionine. The "zipped" concept means only half of the inhibitor needs be constructed; the two halves are then fused by olefin cross-metathesis. Inhibitor design is also mechanism-based, exploiting the favorable kinetics associated with hydrazine-imine interchange as opposed to the usual imine-imine interchange. It is demonstrated that the most potent "zipped" inhibitor 6S reduces H2S production in SH-SY5Y cells overexpressing CBS, thereby reducing cell death. Most importantly, CBS inhibitor 6S dramatically reduces infarct volume (1 h post-stroke treatment; ∼70% reduction) in a rat transient middle cerebral artery occlusion model for ischemia.
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Affiliation(s)
- Christopher
D. McCune
- Department
of Chemistry, University of Nebraska, Lincoln, Nebraska 68588, United States
| | - Su Jing Chan
- Department
of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597
| | - Matthew L. Beio
- Department
of Chemistry, University of Nebraska, Lincoln, Nebraska 68588, United States
| | - Weijun Shen
- Department
of Chemistry, University of Nebraska, Lincoln, Nebraska 68588, United States
| | - Woo Jin Chung
- Department
of Chemistry, University of Nebraska, Lincoln, Nebraska 68588, United States
| | - Laura M. Szczesniak
- Department
of Chemistry, University of Nebraska, Lincoln, Nebraska 68588, United States
| | - Chou Chai
- Neurodegeneration
Research Laboratory, National Neuroscience
Institute, Singapore 308433
| | - Shu Qing Koh
- Department
of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597
| | - Peter T.-H. Wong
- Department
of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597
- (P.T.-H.W.) E-mail:
| | - David B. Berkowitz
- Department
of Chemistry, University of Nebraska, Lincoln, Nebraska 68588, United States
- (D.B.D.) E-mail:
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36
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Carballal S, Cuevasanta E, Yadav PK, Gherasim C, Ballou DP, Alvarez B, Banerjee R. Kinetics of Nitrite Reduction and Peroxynitrite Formation by Ferrous Heme in Human Cystathionine β-Synthase. J Biol Chem 2016; 291:8004-13. [PMID: 26867575 DOI: 10.1074/jbc.m116.718734] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Indexed: 01/01/2023] Open
Abstract
Cystathionine β-synthase (CBS) is a pyridoxal phosphate-dependent enzyme that catalyzes the condensation of homocysteine with serine or with cysteine to form cystathionine and either water or hydrogen sulfide, respectively. Human CBS possesses a noncatalytic heme cofactor with cysteine and histidine as ligands, which in its oxidized state is relatively unreactive. Ferric CBS (Fe(III)-CBS) can be reduced by strong chemical and biochemical reductants to Fe(II)-CBS, which can bind carbon monoxide (CO) or nitric oxide (NO(•)), leading to inactive enzyme. Alternatively, Fe(II)-CBS can be reoxidized by O2to Fe(III)-CBS, forming superoxide radical anion (O2 (̇̄)). In this study, we describe the kinetics of nitrite (NO2 (-)) reduction by Fe(II)-CBS to form Fe(II)NO(•)-CBS. The second order rate constant for the reaction of Fe(II)-CBS with nitrite was obtained at low dithionite concentrations. Reoxidation of Fe(II)NO(•)-CBS by O2showed complex kinetic behavior and led to peroxynitrite (ONOO(-)) formation, which was detected using the fluorescent probe, coumarin boronic acid. Thus, in addition to being a potential source of superoxide radical, CBS constitutes a previously unrecognized source of NO(•)and peroxynitrite.
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Affiliation(s)
- Sebastián Carballal
- From the Departamento de Bioquímica, Facultad de Medicina, Center for Free Radical and Biomedical Research, and
| | - Ernesto Cuevasanta
- Center for Free Radical and Biomedical Research, and Laboratorio de Enzimología, Facultad de Ciencias, Universidad de la República, Montevideo 11800, Uruguay and
| | - Pramod K Yadav
- the Department of Biological Chemistry, Medical Center, University of Michigan, Ann Arbor, Michigan 48109-0600
| | - Carmen Gherasim
- the Department of Biological Chemistry, Medical Center, University of Michigan, Ann Arbor, Michigan 48109-0600
| | - David P Ballou
- the Department of Biological Chemistry, Medical Center, University of Michigan, Ann Arbor, Michigan 48109-0600
| | - Beatriz Alvarez
- Center for Free Radical and Biomedical Research, and Laboratorio de Enzimología, Facultad de Ciencias, Universidad de la República, Montevideo 11800, Uruguay and
| | - Ruma Banerjee
- the Department of Biological Chemistry, Medical Center, University of Michigan, Ann Arbor, Michigan 48109-0600
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37
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Aoto S, Yura K. Case study on the evolution of hetero-oligomer interfaces based on the differences in paralogous proteins. Biophys Physicobiol 2015; 12:103-16. [PMID: 27493859 PMCID: PMC4736837 DOI: 10.2142/biophysico.12.0_103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 11/09/2015] [Indexed: 12/31/2022] Open
Abstract
We addressed the evolutionary trace of hetero-oligomer interfaces by comparing the structures of paralogous proteins; one of them is a monomer or homo-oligomer and the other is a hetero-oligomer. We found different trends in amino acid conservation pattern and hydrophobicity between homo-oligomer and hetero-oligomer. The degree of amino acid conservation in the interface of homo-oligomer has no obvious difference from that in the surface, whereas the degree of conservation is much higher in the interface of hetero-oligomer. The interface of homo-oligomer has a few very conserved residue positions, whereas the residue conservation in the interface of hetero-oligomer tends to be higher. In addition, the interface of hetero-oligomer has a tendency of being more hydrophobic compared with the one in homo-oligomer. We conjecture that these differences are related to the inherent symmetry in homo-oligomers that cannot exist in hetero-oligomers. Paucity of the structural data precludes statistical tests of these tendencies, yet the trend can be applied to the prediction of the interface of hetero-oligomer. We obtained putative interfaces of the subunits in CPSF (cleavage and polyadenylation specificity factor), one of the human pre-mRNA 3′-processing complexes. The locations of predicted interface residues were consistent with the known experimental data.
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Affiliation(s)
- Saki Aoto
- Graduate School of Humanities and Sciences, Ochanomizu University, Bunkyo, Tokyo 112-8610, Japan
| | - Kei Yura
- Graduate School of Humanities and Sciences, Ochanomizu University, Bunkyo, Tokyo 112-8610, Japan; Centre for Informational Biology, Ochanomizu University, Bunkyo, Tokyo 112-8610, Japan; National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
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38
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Shimizu T, Huang D, Yan F, Stranava M, Bartosova M, Fojtíková V, Martínková M. Gaseous O2, NO, and CO in signal transduction: structure and function relationships of heme-based gas sensors and heme-redox sensors. Chem Rev 2015; 115:6491-533. [PMID: 26021768 DOI: 10.1021/acs.chemrev.5b00018] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Toru Shimizu
- †Department of Cell Biology and Genetics and Key Laboratory of Molecular Biology in High Cancer Incidence Coastal Chaoshan Area of Guangdong Higher Education Institutes, Shantou University Medical College, Shantou, Guangdong 515041, China
- ‡Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague 2 128 43, Czech Republic
- §Research Center for Compact Chemical System, National Institute of Advanced Industrial Science and Technology (AIST), Sendai 983-8551, Japan
| | - Dongyang Huang
- †Department of Cell Biology and Genetics and Key Laboratory of Molecular Biology in High Cancer Incidence Coastal Chaoshan Area of Guangdong Higher Education Institutes, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Fang Yan
- †Department of Cell Biology and Genetics and Key Laboratory of Molecular Biology in High Cancer Incidence Coastal Chaoshan Area of Guangdong Higher Education Institutes, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Martin Stranava
- ‡Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague 2 128 43, Czech Republic
| | - Martina Bartosova
- ‡Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague 2 128 43, Czech Republic
| | - Veronika Fojtíková
- ‡Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague 2 128 43, Czech Republic
| | - Markéta Martínková
- ‡Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague 2 128 43, Czech Republic
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39
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Smith AT, Pazicni S, Marvin KA, Stevens DJ, Paulsen KM, Burstyn JN. Functional divergence of heme-thiolate proteins: a classification based on spectroscopic attributes. Chem Rev 2015; 115:2532-58. [PMID: 25763468 DOI: 10.1021/cr500056m] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Aaron T Smith
- †Department of Molecular Biosciences, Northwestern University, 2205 Tech Drive, Evanston, Illinois 60208, United States
| | - Samuel Pazicni
- ‡Department of Chemistry, University of New Hampshire, 23 Academic Way, Durham, New Hampshire 03824, United States
| | - Katherine A Marvin
- §Department of Chemistry, Hendrix College, 1600 Washington Avenue, Conway, Arkansas 72032, United States
| | - Daniel J Stevens
- ∥Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Katherine M Paulsen
- ∥Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Judith N Burstyn
- ∥Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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40
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Niu WN, Yadav PK, Adamec J, Banerjee R. S-glutathionylation enhances human cystathionine β-synthase activity under oxidative stress conditions. Antioxid Redox Signal 2015; 22:350-61. [PMID: 24893130 PMCID: PMC4307034 DOI: 10.1089/ars.2014.5891] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
AIMS Cystathionine β-synthase (CBS) catalyzes the first and rate-limiting step in the two-step trans-sulfuration pathway that converts homocysteine to cysteine. It is also one of three major enzymes responsible for the biogenesis of H2S, a signaling molecule. We have previously demonstrated that CBS is activated in cells challenged by oxidative stress, but the underlying molecular mechanism of this regulation has remained unclear. RESULTS Here, we demonstrate that S-glutathionylation of CBS enhances its activity ∼2-fold in vitro. Loss of this post-translational modification in the presence of dithiothreitol results in reversal to basal activity. Cys346 was identified as the site for S-glutathionylation by a combination of mass spectrometric, mutagenesis, and activity analyses. To test the physiological relevance of S-glutathionylation-dependent regulation of CBS, HEK293 cells were oxidatively challenged with peroxide, which is known to enhance the trans-sulfuration flux. Under these conditions, CBS glutathionylation levels increased and were correlated with a ∼3-fold increase in CBS activity. INNOVATION Collectively, our results reveal a novel post-translational modification of CBS, that is, glutathionylation, which functions as an allosteric activator under oxidative stress conditions permitting enhanced synthesis of both cysteine and H2S. CONCLUSIONS Our study elucidates a molecular mechanism for increased cysteine and therefore glutathione, synthesis via glutathionylation of CBS. They also demonstrate the potential for increased H2S production under oxidative stress conditions, particularly in tissues where CBS is a major source of H2S.
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Affiliation(s)
- Wei-Ning Niu
- 1 The Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University , Xi'an, China
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41
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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.
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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,
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42
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Structural insight into the molecular mechanism of allosteric activation of human cystathionine β-synthase by S-adenosylmethionine. Proc Natl Acad Sci U S A 2014; 111:E3845-52. [PMID: 25197074 DOI: 10.1073/pnas.1414545111] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cystathionine β-synthase (CBS) is a heme-dependent and pyridoxal-5'-phosphate-dependent protein that controls the flux of sulfur from methionine to cysteine, a precursor of glutathione, taurine, and H2S. Deficiency of CBS activity causes homocystinuria, the most frequent disorder of sulfur amino acid metabolism. In contrast to CBSs from lower organisms, human CBS (hCBS) is allosterically activated by S-adenosylmethionine (AdoMet), which binds to the regulatory domain and triggers a conformational change that allows the protein to progress from the basal toward the activated state. The structural basis of the underlying molecular mechanism has remained elusive so far. Here, we present the structure of hCBS with bound AdoMet, revealing the activated conformation of the human enzyme. Binding of AdoMet triggers a conformational change in the Bateman module of the regulatory domain that favors its association with a Bateman module of the complementary subunit to form an antiparallel CBS module. Such an arrangement is very similar to that found in the constitutively activated insect CBS. In the presence of AdoMet, the autoinhibition exerted by the regulatory region is eliminated, allowing for improved access of substrates to the catalytic pocket. Based on the availability of both the basal and the activated structures, we discuss the mechanism of hCBS activation by AdoMet and the properties of the AdoMet binding site, as well as the responsiveness of the enzyme to its allosteric regulator. The structure described herein paves the way for the rational design of compounds modulating hCBS activity and thus transsulfuration, redox status, and H2S biogenesis.
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43
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Mendes MIS, Santos AS, Smith DEC, Lino PR, Colaço HG, de Almeida IT, Vicente JB, Salomons GS, Rivera I, Blom HJ, Leandro P. Insights into the regulatory domain of cystathionine Beta-synthase: characterization of six variant proteins. Hum Mutat 2014; 35:1195-202. [PMID: 25044645 DOI: 10.1002/humu.22616] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 06/30/2014] [Indexed: 11/07/2022]
Abstract
Cystathionine beta-synthase (CBS) catalyzes the formation of cystathionine from homocysteine and serine. CBS is allosterically activated by S-adenosylmethionine (SAM), which binds to its C-terminal regulatory domain. Mutations in this domain lead to variants with high residual activity but lacking SAM activation. We characterized six C-terminal CBS variants (p.P427L, p.D444N, p.V449G, p.S500L, p.K523Sfs*18, and p.L540Q). To understand the effect of C-terminal mutations on the functional/structural properties of CBS, we performed dynamic light scattering, differential scanning fluorimetry, limited proteolysis, enzymatic characterization, and determination of SAM-binding affinity. Kinetic data confirm that the enzymatic function of these variants is not impaired. Although lacking SAM activation, the p.P427L and p.S500L were able to bind SAM at a lower extent than the wild type (WT), confirming that SAM binding and activation can be two independent events. At the structural level, the C-terminal variants presented various effects, either showing catalytic core instability and increased susceptibility toward aggregation or presenting with similar or higher stability than the WT. Our study highlights as the common feature to the C-terminal variants an impaired binding of SAM and no increase in enzymatic activity with physiological concentrations of the activator, suggesting the loss of regulation by SAM as a potential pathogenic mechanism.
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Affiliation(s)
- Marisa I S Mendes
- Metabolism and Genetics Group, Research Institute for Medicines, Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal; Metabolic Unit, Department of Clinical Chemistry, VU University Medical Centre, Amsterdam, The Netherlands
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44
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Pey AL, Majtan T, Kraus JP. The role of surface electrostatics on the stability, function and regulation of human cystathionine β-synthase, a complex multidomain and oligomeric protein. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:1453-62. [PMID: 24780582 DOI: 10.1016/j.bbapap.2014.04.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 04/06/2014] [Accepted: 04/21/2014] [Indexed: 11/25/2022]
Abstract
Human cystathionine β-synthase (hCBS) is a key enzyme of sulfur amino acid metabolism, controlling the commitment of homocysteine to the transsulfuration pathway and antioxidant defense. Mutations in hCBS cause inherited homocystinuria (HCU), a rare inborn error of metabolism characterized by accumulation of toxic homocysteine in blood and urine. hCBS is a complex multidomain and oligomeric protein whose activity and stability are independently regulated by the binding of S-adenosyl-methionine (SAM) to two different types of sites at its C-terminal regulatory domain. Here we study the role of surface electrostatics on the complex regulation and stability of hCBS using biophysical and biochemical procedures. We show that the kinetic stability of the catalytic and regulatory domains is significantly affected by the modulation of surface electrostatics through noticeable structural and energetic changes along their denaturation pathways. We also show that surface electrostatics strongly affect SAM binding properties to those sites responsible for either enzyme activation or kinetic stabilization. Our results provide new insight into the regulation of hCBS activity and stability in vivo with implications for understanding HCU as a conformational disease. We also lend experimental support to the role of electrostatic interactions in the recently proposed binding modes of SAM leading to hCBS activation and kinetic stabilization.
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Affiliation(s)
- Angel L Pey
- Department of Physical Chemistry, Faculty of Sciences, University of Granada, Av. Fuentenueva s/n, 18071 Granada, Spain.
| | - Tomas Majtan
- Department of Pediatrics, University of Colorado, School of Medicine, Aurora, CO 80045, USA
| | - Jan P Kraus
- Department of Pediatrics, University of Colorado, School of Medicine, Aurora, CO 80045, USA
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45
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Ereño-Orbea J, Majtan T, Oyenarte I, Kraus JP, Martínez-Cruz LA. Purification, crystallization and preliminary crystallographic analysis of the catalytic core of cystathionine β-synthase from Saccharomyces cerevisiae. Acta Crystallogr F Struct Biol Commun 2014; 70:320-5. [PMID: 24598918 PMCID: PMC3944693 DOI: 10.1107/s2053230x14001502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2013] [Accepted: 01/21/2014] [Indexed: 11/10/2022] Open
Abstract
Cystathionine β-synthase (CBS; EC 4.2.1.22) catalyzes the condensation of homocysteine and serine to form cystathionine, with the release of water. In humans, deficiency in CBS activity is the most common cause of hyperhomocysteinaemia and homocystinuria. More than 160 pathogenic mutations in the human CBS gene have been described to date. Here, the purification and preliminary crystallographic analysis of the catalytic core of CBS from Saccharomyces cerevisiae (ScCBS) is described which, in contrast to other eukaryotic CBSs, lacks the N-terminal haem-binding domain and is considered to be a useful model for investigation of the pyridoxal-5'-phosphate-mediated reactions of human CBS (hCBS). The purified protein yielded two different crystal forms belonging to space groups P41212 and P212121, with unit-cell parameters a = b = 72.390, c = 386.794 Å and a = 58.156, b = 89.988, c = 121.687 Å, respectively. Diffraction data were collected to 2.7 and 3.1 Å resolution, respectively, using synchrotron radiation. Preliminary analysis of the X-ray data suggests the presence of ScCBS homodimers in both types of crystals.
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Affiliation(s)
- June Ereño-Orbea
- Structural Biology Unit, CIC bioGUNE, Parque Tecnológico de Bizkaia, Edificio 800, 48160 Derio, Bizkaia , Spain
| | - Tomas Majtan
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Iker Oyenarte
- Structural Biology Unit, CIC bioGUNE, Parque Tecnológico de Bizkaia, Edificio 800, 48160 Derio, Bizkaia , Spain
| | - Jan P. Kraus
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Luis Alfonso Martínez-Cruz
- Structural Biology Unit, CIC bioGUNE, Parque Tecnológico de Bizkaia, Edificio 800, 48160 Derio, Bizkaia , Spain
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46
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Mendes MIS, Colaço HG, Smith DEC, Ramos RJJF, Pop A, van Dooren SJM, Tavares de Almeida I, Kluijtmans LAJ, Janssen MCH, Rivera I, Salomons GS, Leandro P, Blom HJ. Reduced response of Cystathionine Beta-Synthase (CBS) to S-Adenosylmethionine (SAM): Identification and functional analysis of CBS gene mutations in Homocystinuria patients. J Inherit Metab Dis 2014; 37:245-54. [PMID: 23974653 DOI: 10.1007/s10545-013-9647-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 07/29/2013] [Accepted: 07/30/2013] [Indexed: 11/29/2022]
Abstract
A reduced response of cystathionine beta-synthase (CBS) to its allosteric activator S-adenosylmethionine (SAM) has been reported to be a cause of CBS dysfunction in homocystinuria patients. In this work we performed a retrospective analysis of fibroblast data from 62 homocystinuria patients and found that 13 of them presented a disturbed SAM activation. Their genotypic background was identified and the corresponding CBS mutant proteins were produced in E. coli. Nine distinct mutations were detected in 22 independent alleles: the novel mutations p.K269del, p.P427L, p.S500L and p.L540Q; and the previously described mutations p.P49L, p.C165Rfs*2, p.I278T, p.R336H and p.D444N. Expression levels and residual enzyme activities, determined in the soluble fraction of E. coli lysates, strongly correlated with the localization of the affected amino acid residue. C-terminal mutations lead to activities in the range of the wild-type CBS and to oligomeric forms migrating faster than tetramers, suggesting an abnormal conformation that might be responsible for the lack of SAM activation. Mutations in the catalytic core were associated with low protein expression levels, decreased enzyme activities and a higher content of high molecular mass forms. Furthermore, the absence of SAM activation found in the patients' fibroblasts was confirmed for all but one of the characterized recombinant proteins (p.P49L). Our study experimentally supports a deficient regulation of CBS by SAM as a frequently found mechanism in CBS deficiency, which should be considered not only as a valuable diagnostic tool but also as a potential target for the development of new therapeutic approaches in classical homocystinuria.
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Affiliation(s)
- Marisa I S Mendes
- Metabolism and Genetics Group, Research Institute for Medicines and Pharmaceutical Sciences, Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal
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47
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Vicente JB, Colaço HG, Mendes MIS, Sarti P, Leandro P, Giuffrè A. NO* binds human cystathionine β-synthase quickly and tightly. J Biol Chem 2014; 289:8579-87. [PMID: 24515102 DOI: 10.1074/jbc.m113.507533] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The hexa-coordinate heme in the H2S-generating human enzyme cystathionine β-synthase (CBS) acts as a redox-sensitive regulator that impairs CBS activity upon binding of NO(•) or CO at the reduced iron. Despite the proposed physiological relevance of this inhibitory mechanism, unlike CO, NO(•) was reported to bind at the CBS heme with very low affinity (Kd = 30-281 μm). This discrepancy was herein reconciled by investigating the NO(•) reactivity of recombinant human CBS by static and stopped-flow UV-visible absorption spectroscopy. We found that NO(•) binds tightly to the ferrous CBS heme, with an apparent Kd ≤ 0.23 μm. In line with this result, at 25 °C, NO(•) binds quickly to CBS (k on ∼ 8 × 10(3) m(-1) s(-1)) and dissociates slowly from the enzyme (k off ∼ 0.003 s(-1)). The observed rate constants for NO(•) binding were found to be linearly dependent on [NO(•)] up to ∼ 800 μm NO(•), and >100-fold higher than those measured for CO, indicating that the reaction is not limited by the slow dissociation of Cys-52 from the heme iron, as reported for CO. For the first time the heme of human CBS is reported to bind NO(•) quickly and tightly, providing a mechanistic basis for the in vivo regulation of the enzyme by NO(•). The novel findings reported here shed new light on CBS regulation by NO(•) and its possible (patho)physiological relevance, enforcing the growing evidence for an interplay among the gasotransmitters NO(•), CO, and H2S in cell signaling.
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Affiliation(s)
- João B Vicente
- From the Metabolism and Genetics Group, Research Institute for Medicines and Pharmaceutical Sciences (iMed.UL), Faculty of Pharmacy, University of Lisbon, 1649-003 Lisbon, Portugal
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48
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Gherasim C, Yadav PK, Kabil O, Niu WN, Banerjee R. Nitrite reductase activity and inhibition of H₂S biogenesis by human cystathionine ß-synthase. PLoS One 2014; 9:e85544. [PMID: 24416422 PMCID: PMC3885727 DOI: 10.1371/journal.pone.0085544] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 12/04/2013] [Indexed: 12/18/2022] Open
Abstract
Nitrite was recognized as a potent vasodilator >130 years and has more recently emerged as an endogenous signaling molecule and modulator of gene expression. Understanding the molecular mechanisms that regulate nitrite metabolism is essential for its use as a potential diagnostic marker as well as therapeutic agent for cardiovascular diseases. In this study, we have identified human cystathionine ß-synthase (CBS) as a new player in nitrite reduction with implications for the nitrite-dependent control of H2S production. This novel activity of CBS exploits the catalytic property of its unusual heme cofactor to reduce nitrite and generate NO. Evidence for the possible physiological relevance of this reaction is provided by the formation of ferrous-nitrosyl (FeII-NO) CBS in the presence of NADPH, the human diflavin methionine synthase reductase (MSR) and nitrite. Formation of FeII-NO CBS via its nitrite reductase activity inhibits CBS, providing an avenue for regulating biogenesis of H2S and cysteine, the limiting reagent for synthesis of glutathione, a major antioxidant. Our results also suggest a possible role for CBS in intracellular NO biogenesis particularly under hypoxic conditions. The participation of a regulatory heme cofactor in CBS in nitrite reduction is unexpected and expands the repertoire of proteins that can liberate NO from the intracellular nitrite pool. Our results reveal a potential molecular mechanism for cross-talk between nitrite, NO and H2S biology.
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Affiliation(s)
- Carmen Gherasim
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Pramod K. Yadav
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Omer Kabil
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Wei-Ning Niu
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- School of Life Science, Northwestern Polytechnical University, Xi’an, China
| | - Ruma Banerjee
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- * E-mail:
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49
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Structural basis of regulation and oligomerization of human cystathionine β-synthase, the central enzyme of transsulfuration. Proc Natl Acad Sci U S A 2013; 110:E3790-9. [PMID: 24043838 DOI: 10.1073/pnas.1313683110] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cystathionine β-synthase (CBS) controls the flux of sulfur from methionine to cysteine, a precursor of glutathione, taurine, and H2S. CBS condenses serine and homocysteine to cystathionine with the help of three cofactors, heme, pyridoxal-5'-phosphate, and S-adenosyl-l-methionine. Inherited deficiency of CBS activity causes homocystinuria, the most frequent disorder of sulfur metabolism. We present the structure of the human enzyme, discuss the unique arrangement of the CBS domains in the C-terminal region, and propose how they interact with the catalytic core of the complementary subunit to regulate access to the catalytic site. This arrangement clearly contrasts with other proteins containing the CBS domain including the recent Drosophila melanogaster CBS structure. The absence of large conformational changes and the crystal structure of the partially activated pathogenic D444N mutant suggest that the rotation of CBS motifs and relaxation of loops delineating the entrance to the catalytic site represent the most likely molecular mechanism of CBS activation by S-adenosyl-l-methionine. Moreover, our data suggest how tetramers, the native quaternary structure of the mammalian CBS enzymes, are formed. Because of its central role in transsulfuration, redox status, and H2S biogenesis, CBS represents a very attractive therapeutic target. The availability of the structure will help us understand the pathogenicity of the numerous missense mutations causing inherited homocystinuria and will allow the rational design of compounds modulating CBS activity.
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50
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Casique L, Kabil O, Banerjee R, Martinez JC, De Lucca M. Characterization of two pathogenic mutations in cystathionine beta-synthase: different intracellular locations for wild-type and mutant proteins. Gene 2013; 531:117-24. [PMID: 23981774 DOI: 10.1016/j.gene.2013.08.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 06/26/2013] [Accepted: 08/07/2013] [Indexed: 10/26/2022]
Abstract
Cystathionine β-synthase (CBS) is a pyridoxal 5'-phosphate (PLP)-dependent enzyme that catalyzes the condensation of homocysteine with serine to generate cystathionine. Homocystinuria is an autosomal recessive disorder commonly caused by a deficiency of CBS activity. Here, we characterized a novel CBS mutation (c.260C>A (p.T87N)) and a previously reported variant (c.700G>A (p.D234N)) found in Venezuelan homocystinuric patients, one nonresponsive and one responsive to vitamin B6. Both mutant proteins were expressed in vitro in prokaryotic and eukaryotic cells, finding lower soluble expression in HEK-293 cells (19% T87N and 23% D234N) compared to wild-type CBS. Residual activities obtained for the mutant proteins were 3.5% T87N and 43% D234N. Gel exclusion chromatography demonstrated a tendency of the T87N mutant to aggregate while the distribution of the D234N mutant was similar to wild-type enzyme. Using immunofluorescence microscopy, an unexpected difference in intracellular localization was observed between the wild-type and mutant proteins. While the T87N mutant exhibited a punctate appearance, the wild-type protein was homogeneously distributed inside the cell. Interestingly, the D234N protein showed both distributions. This study demonstrates that the pathogenic CBS mutations generate unstable proteins that are unable (T87N) or partially unable (D234N) to assemble into a functional enzyme, implying that these mutations might be responsible for the homocystinuria phenotype.
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Affiliation(s)
- L Casique
- Departamento de Biología Celular, Universidad Simón Bolívar, Caracas 1081-A, Venezuela; Laboratorio de Estudio Molecular de Enfermedades Hereditarias, Fundación IDEA, Caracas 1080-A, Venezuela.
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