1
|
Leo G, Leone P, Ataie Kachoie E, Tolomeo M, Galluccio M, Indiveri C, Barile M, Capaldi S. Structural insights into the bifunctional enzyme human FAD synthase. Structure 2024; 32:953-965.e5. [PMID: 38688286 DOI: 10.1016/j.str.2024.04.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/20/2024] [Accepted: 04/03/2024] [Indexed: 05/02/2024]
Abstract
Human flavin adenine dinucleotide synthase (hFADS) is a bifunctional, multi-domain enzyme that exhibits both flavin mononucleotide adenylyltransferase and pyrophosphatase activities. Here we report the crystal structure of full-length hFADS2 and its C-terminal PAPS domain in complex with flavin adenine dinucleotide (FAD), and dissect the structural determinants underlying the contribution of each individual domain, within isoforms 1 and 2, to each of the two enzymatic activities. Structural and functional characterization performed on complete or truncated constructs confirmed that the C-terminal domain tightly binds FAD and catalyzes its synthesis, while the combination of the N-terminal molybdopterin-binding and KH domains is the minimal essential substructure required for the hydrolysis of FAD and other ADP-containing dinucleotides. hFADS2 associates in a stable C2-symmetric dimer, in which the packing of the KH domain of one protomer against the N-terminal domain of the other creates the adenosine-specific active site responsible for the hydrolytic activity.
Collapse
Affiliation(s)
- Giulia Leo
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Piero Leone
- Department of Biosciences, Biotechnology and Environment, University of Bari, via Orabona 4, 70126 Bari, Italy
| | - Elham Ataie Kachoie
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Maria Tolomeo
- Department of Biosciences, Biotechnology and Environment, University of Bari, via Orabona 4, 70126 Bari, Italy; Department of Biology, Ecology and Earth Sciences (DiBEST), Laboratory of Biochemistry, Molecular Biotechnology, and Molecular Biology, University of Calabria, via P. Bucci 4c, 6c, 87036 Arcavacata di Rende, Italy
| | - Michele Galluccio
- Department of Biology, Ecology and Earth Sciences (DiBEST), Laboratory of Biochemistry, Molecular Biotechnology, and Molecular Biology, University of Calabria, via P. Bucci 4c, 6c, 87036 Arcavacata di Rende, Italy
| | - Cesare Indiveri
- Department of Biology, Ecology and Earth Sciences (DiBEST), Laboratory of Biochemistry, Molecular Biotechnology, and Molecular Biology, University of Calabria, via P. Bucci 4c, 6c, 87036 Arcavacata di Rende, Italy; National Research Council (CNR), Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), via Amendola 122/O, 70126 Bari, Italy
| | - Maria Barile
- Department of Biosciences, Biotechnology and Environment, University of Bari, via Orabona 4, 70126 Bari, Italy.
| | - Stefano Capaldi
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy.
| |
Collapse
|
2
|
Alteration of Flavin Cofactor Homeostasis in Human Neuromuscular Pathologies. Methods Mol Biol 2021; 2280:275-295. [PMID: 33751442 DOI: 10.1007/978-1-0716-1286-6_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The aim of this short review chapter is to provide a brief summary of the relevance of riboflavin (Rf or vitamin B2) and its derived cofactors flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) for human neuromuscular bioenergetics.Therefore, as a completion of this book we would like to summarize what kind of human pathologies could derive from genetic disturbances of Rf transport, flavin cofactor synthesis and delivery to nascent apoflavoproteins, as well as by alteration of vitamin recycling during protein turnover.
Collapse
|
3
|
Leone P, Tolomeo M, Barile M. Continuous and Discontinuous Approaches to Study FAD Synthesis and Degradation Catalyzed by Purified Recombinant FAD Synthase or Cellular Fractions. Methods Mol Biol 2021; 2280:87-116. [PMID: 33751431 DOI: 10.1007/978-1-0716-1286-6_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Riboflavin, or vitamin B2, is the precursor of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), essential redox (and sometimes non-redox) cofactors of a large number of flavoenzymes involved in energetic metabolism, protein folding, apoptosis, chromatin remodeling, and a number of other cell regulatory processes.The cellular and subcellular steady-state concentrations of flavin cofactors, which are available for flavoprotein biogenesis and assembly, depend on carrier-mediated transport processes and on coordinated synthesizing/destroying enzymatic activities, catalyzed by enzymes whose catalytic and structural properties are still matter of investigation.Alteration of flavin homeostasis has been recently correlated to human pathological conditions, such as neuromuscular disorders and cancer, and therefore we propose here protocols useful to detect metabolic processes involved in FAD forming and destroying.Our protocols exploit the chemical-structural differences between riboflavin, FMN , and FAD , which are responsible for differences in the spectroscopic properties (mainly fluorescence) of the two cofactors (FMN and FAD); therefore, in our opinion, when applicable measurements of fluorescence changes in continuo represent the elective techniques to follow FAD synthesis and degradation. Thus, after procedures able to calibrate flavin concentrations (Subheading 3.1), we describe simple continuous and rapid procedures, based on the peculiar optical properties of free flavins, useful to determine the rate of cofactor metabolism catalyzed by either recombinant enzymes or natural enzymes present in cellular lysates/subfractions (Subheading 3.2).Fluorescence properties of free flavins can also be useful in analytical determinations of the three molecular flavin forms, based on HPLC separation, with a quite high sensitivity. Assaying at different incubation times the molecular composition of the reaction mixture is a discontinuous experimental approach to measure the rate of FAD synthesis/degradation catalyzed by cell lysates or recombinant FAD synthase (Subheading 3.3). Continuous and discontinuous approaches can, when necessary, be performed in parallel.
Collapse
Affiliation(s)
- Piero Leone
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari "A. Moro", Bari, Italy
| | - Maria Tolomeo
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari "A. Moro", Bari, Italy
| | - Maria Barile
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari "A. Moro", Bari, Italy.
| |
Collapse
|
4
|
Tolomeo M, Nisco A, Leone P, Barile M. Development of Novel Experimental Models to Study Flavoproteome Alterations in Human Neuromuscular Diseases: The Effect of Rf Therapy. Int J Mol Sci 2020; 21:ijms21155310. [PMID: 32722651 PMCID: PMC7432027 DOI: 10.3390/ijms21155310] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 02/07/2023] Open
Abstract
Inborn errors of Riboflavin (Rf) transport and metabolism have been recently related to severe human neuromuscular disorders, as resulting in profound alteration of human flavoproteome and, therefore, of cellular bioenergetics. This explains why the interest in studying the “flavin world”, a topic which has not been intensively investigated before, has increased much over the last few years. This also prompts basic questions concerning how Rf transporters and FAD (flavin adenine dinucleotide) -forming enzymes work in humans, and how they can create a coordinated network ensuring the maintenance of intracellular flavoproteome. The concept of a coordinated cellular “flavin network”, introduced long ago studying humans suffering for Multiple Acyl-CoA Dehydrogenase Deficiency (MADD), has been, later on, addressed in model organisms and more recently in cell models. In the frame of the underlying relevance of a correct supply of Rf in humans and of a better understanding of the molecular rationale of Rf therapy in patients, this review wants to deal with theories and existing experimental models in the aim to potentiate possible therapeutic interventions in Rf-related neuromuscular diseases.
Collapse
|
5
|
Insights into the FMNAT Active Site of FAD Synthase: Aromaticity is Essential for Flavin Binding and Catalysis. Int J Mol Sci 2020; 21:ijms21103738. [PMID: 32466340 PMCID: PMC7279473 DOI: 10.3390/ijms21103738] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 05/21/2020] [Accepted: 05/22/2020] [Indexed: 11/17/2022] Open
Abstract
The last step in the biosynthesis of flavin adenine dinucleotide (FAD) is considered a target for the design of antimicrobial drugs because it is carried out by two non-homologous proteins in eukaryotic and prokaryotic organisms. Monofunctional FMN: adenylyltransferases (FMNAT) in Eukarya and FMNAT modules of bifunctional FAD synthases (FADS) in Prokarya belong to different structural families with dissimilar chemistry and binding modes for the substrates. In this study, we analyzed the relevance of the hydrophobic environment of the flavin isoalloxazine in the FMNAT active site of Corynebacterium ammoniagenes FADS (CaFADS) through the mutational analysis of its F62, Y106, and F128 residues. They form the isoalloxazine binding cavity and are highly conserved in the prokaryotic FADS family. The spectroscopic, steady-state kinetics and thermodynamic data presented indicate that distortion of aromaticity at the FMNAT isoalloxazine binding cavity prevents FMN and FAD from correct accommodation in their binding cavity and, as a consequence, decreases the efficiency of the FMNAT activity. Therefore, the side-chains of F62, Y106 and F128 are relevant in the formation of the catalytic competent complex during FMNAT catalysis in CaFADS. The introduced mutations also modulate the activity occurring at the riboflavin kinase (RFK) module of CaFADS, further evidencing the formation of quaternary assemblies during catalysis.
Collapse
|
6
|
Leone P, Galluccio M, Quarta S, Anoz-Carbonell E, Medina M, Indiveri C, Barile M. Mutation of Aspartate 238 in FAD Synthase Isoform 6 Increases the Specific Activity by Weakening the FAD Binding. Int J Mol Sci 2019; 20:ijms20246203. [PMID: 31835305 PMCID: PMC6941110 DOI: 10.3390/ijms20246203] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 12/04/2019] [Accepted: 12/06/2019] [Indexed: 02/07/2023] Open
Abstract
FAD synthase (FADS, or FMN:ATP adenylyl transferase) coded by the FLAD1 gene is the last enzyme in the pathway of FAD synthesis. The mitochondrial isoform 1 and the cytosolic isoform 2 are characterized by the following two domains: the C-terminal PAPS domain (FADSy) performing FAD synthesis and pyrophosphorolysis; the N-terminal molybdopterin-binding domain (FADHy) performing a Co++/K+-dependent FAD hydrolysis. Mutations in FLAD1 gene are responsible for riboflavin responsive and non-responsive multiple acyl-CoA dehydrogenases and combined respiratory chain deficiency. In patients harboring frameshift mutations, a shorter isoform (hFADS6) containing the sole FADSy domain is produced representing an emergency protein. With the aim to ameliorate its function we planned to obtain an engineered more efficient hFADS6. Thus, the D238A mutant, resembling the D181A FMNAT “supermutant” of C. glabrata, was overproduced and purified. Kinetic analysis of this enzyme highlighted a general increase of Km, while the kcat was two-fold higher than that of WT. The data suggest that the FAD synthesis rate can be increased. Additional modifications could be performed to further improve the synthesis of FAD. These results correlate with previous data produced in our laboratory, and point towards the following proposals (i) FAD release is the rate limiting step of the catalytic cycle and (ii) ATP and FMN binding sites are synergistically connected.
Collapse
Affiliation(s)
- Piero Leone
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, via Orabona 4–, 70126 Bari, Italy; (P.L.); (S.Q.)
- Department of Biology, Ecology and Earth Sciences (DiBEST), Unit of Biochemistry and Molecular Biotechnology, University of Calabria, via P. Bucci 4c, 87036 Arcavacata di Rende, Italy; (M.G.); (C.I.)
| | - Michele Galluccio
- Department of Biology, Ecology and Earth Sciences (DiBEST), Unit of Biochemistry and Molecular Biotechnology, University of Calabria, via P. Bucci 4c, 87036 Arcavacata di Rende, Italy; (M.G.); (C.I.)
| | - Stefano Quarta
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, via Orabona 4–, 70126 Bari, Italy; (P.L.); (S.Q.)
| | - Ernesto Anoz-Carbonell
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, 50009 Zaragoza, Spain; (E.A.-C.); (M.M.)
| | - Milagros Medina
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, 50009 Zaragoza, Spain; (E.A.-C.); (M.M.)
| | - Cesare Indiveri
- Department of Biology, Ecology and Earth Sciences (DiBEST), Unit of Biochemistry and Molecular Biotechnology, University of Calabria, via P. Bucci 4c, 87036 Arcavacata di Rende, Italy; (M.G.); (C.I.)
| | - Maria Barile
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, via Orabona 4–, 70126 Bari, Italy; (P.L.); (S.Q.)
- Correspondence:
| |
Collapse
|
7
|
Leone P, Galluccio M, Brizio C, Barbiroli A, Iametti S, Indiveri C, Barile M. The hidden side of the human FAD synthase 2. Int J Biol Macromol 2019; 138:986-995. [PMID: 31351152 DOI: 10.1016/j.ijbiomac.2019.07.138] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 07/22/2019] [Accepted: 07/23/2019] [Indexed: 11/16/2022]
Abstract
FAD synthase, the last enzyme of the pathway converting riboflavin to FAD, exists in humans in different isoforms, with isoforms 1, 2 and 6 being characterized at the functional and molecular levels. Isoform 2, the cytosolic and most abundant FADS, consists of two domains: a PAPS reductase C-terminus domain (here named FADSy) responsible for FAD synthesis, and an N-terminus molybdopterin-binding resembling domain (MPTb - here named FADHy), whose FAD hydrolytic activity is hidden unless both Co2+ and chemical mercurial reagents are added to the enzyme. To investigate the hFADS2 hydrolytic function under conditions closer to the physiological context, the hydrolytic activity was further characterized. Co2+ induced FAD hydrolysis was strongly stimulated in the presence of K+, reaching a Vmax higher than that of FAD synthesis. The pH dependence together with the inhibition of the hydrolysis by NaF and KI allow excluding that the reaction occurs via a NUDIX type catalysis. The K0.5 for K+ or Co2+ was 7.2 or 0.035 mM, respectively. Other monovalent or divalent cations can partially substitute K+ or Co2+. Reduced glutathione stimulated whereas NADH inhibited the hydrolytic activity. The latter aspects correlate with an interconnection of the homeostasis of NAD and FAD.
Collapse
Affiliation(s)
- Piero Leone
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, via Orabona 4 -, 70126 Bari, Italy; Department of Biology, Ecology and Earth Sciences (DiBEST), Unit of Biochemistry and Molecular Biotechnology, University of Calabria, via P. Bucci 4c, , 87036 Arcavacata di Rende, Italy
| | - Michele Galluccio
- Department of Biology, Ecology and Earth Sciences (DiBEST), Unit of Biochemistry and Molecular Biotechnology, University of Calabria, via P. Bucci 4c, , 87036 Arcavacata di Rende, Italy
| | - Carmen Brizio
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, via Orabona 4 -, 70126 Bari, Italy
| | - Alberto Barbiroli
- Dipartimento di Scienze per gli Alimenti, la Nutrizione e l'Ambiente (DeFENS), Università degli Studi di Milano, via Celoria 2, I-20133 Milano, Italy
| | - Stefania Iametti
- Dipartimento di Scienze per gli Alimenti, la Nutrizione e l'Ambiente (DeFENS), Università degli Studi di Milano, via Celoria 2, I-20133 Milano, Italy
| | - Cesare Indiveri
- Department of Biology, Ecology and Earth Sciences (DiBEST), Unit of Biochemistry and Molecular Biotechnology, University of Calabria, via P. Bucci 4c, , 87036 Arcavacata di Rende, Italy; Institute of Biomembranes, Bioenergetics and Molecular Biotechnology (IBIOM) - CNR, via Giovanni Amendola 165/A, 70126 Bari, Italy
| | - Maria Barile
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, via Orabona 4 -, 70126 Bari, Italy.
| |
Collapse
|
8
|
Giangregorio N, Tonazzi A, Console L, Galluccio M, Porcelli V, Indiveri C. Structure/function relationships of the human mitochondrial ornithine/citrulline carrier by Cys site-directed mutagenesis. Relevance to mercury toxicity. Int J Biol Macromol 2018; 120:93-99. [DOI: 10.1016/j.ijbiomac.2018.08.069] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 08/12/2018] [Accepted: 08/14/2018] [Indexed: 12/19/2022]
|
9
|
Bacterial Production, Characterization and Protein Modeling of a Novel Monofuctional Isoform of FAD Synthase in Humans: An Emergency Protein? Molecules 2018; 23:molecules23010116. [PMID: 29316637 PMCID: PMC6017331 DOI: 10.3390/molecules23010116] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Revised: 12/30/2017] [Accepted: 01/04/2018] [Indexed: 12/13/2022] Open
Abstract
FAD synthase (FADS, EC 2.7.7.2) is the last essential enzyme involved in the pathway of biosynthesis of Flavin cofactors starting from Riboflavin (Rf). Alternative splicing of the human FLAD1 gene generates different isoforms of the enzyme FAD synthase. Besides the well characterized isoform 1 and 2, other FADS isoforms with different catalytic domains have been detected, which are splice variants. We report the characterization of one of these novel isoforms, a 320 amino acid protein, consisting of the sole C-terminal 3′-phosphoadenosine 5′-phosphosulfate (PAPS) reductase domain (named FADS6). This isoform has been previously detected in Riboflavin-Responsive (RR-MADD) and Non-responsive Multiple Acyl-CoA Dehydrogenase Deficiency (MADD) patients with frameshift mutations of FLAD1 gene. To functionally characterize the hFADS6, it has been over-expressed in Escherichia coli and purified with a yield of 25 mg·L−1 of cell culture. The protein has a monomeric form, it binds FAD and is able to catalyze FAD synthesis (kcat about 2.8 min−1), as well as FAD pyrophosphorolysis in a strictly Mg2+-dependent manner. The synthesis of FAD is inhibited by HgCl2. The enzyme lacks the ability to hydrolyze FAD. It behaves similarly to PAPS. Combining threading and ab-initio strategy a 3D structural model for such isoform has been built. The relevance to human physio-pathology of this FADS isoform is discussed.
Collapse
|
10
|
Barile M, Giancaspero TA, Leone P, Galluccio M, Indiveri C. Riboflavin transport and metabolism in humans. J Inherit Metab Dis 2016; 39:545-57. [PMID: 27271694 DOI: 10.1007/s10545-016-9950-0] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 05/12/2016] [Accepted: 05/19/2016] [Indexed: 12/17/2022]
Abstract
Recent studies elucidated how riboflavin transporters and FAD forming enzymes work in humans and create a coordinated flavin network ensuring the maintenance of cellular flavoproteome. Alteration of this network may be causative of severe metabolic disorders such as multiple acyl-CoA dehydrogenase deficiency (MADD) or Brown-Vialetto-van Laere syndrome. A crucial step in the maintenance of FAD homeostasis is riboflavin uptake by plasma and mitochondrial membranes. Therefore, studies on recently identified human plasma membrane riboflavin transporters are presented, together with those in which still unidentified mitochondrial riboflavin transporter(s) have been described. A main goal of future research is to fill the gaps still existing as for some transcriptional, functional and structural details of human FAD synthases (FADS) encoded by FLAD1 gene, a novel "redox sensing" enzyme. In the frame of the hypothesis that FADS, acting as a "FAD chaperone", could play a crucial role in the biogenesis of mitochondrial flavo-proteome, several basic functional aspects of flavin cofactor delivery to cognate apo-flavoenzyme are also briefly dealt with. The establishment of model organisms performing altered FAD homeostasis will improve the molecular description of human pathologies. The molecular and functional studies of transporters and enzymes herereported, provide guidelines for improving therapies which may have beneficial effects on the altered metabolism.
Collapse
Affiliation(s)
- Maria Barile
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari "Aldo Moro", via Orabona 4, I-70126, Bari, Italy.
| | - Teresa Anna Giancaspero
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari "Aldo Moro", via Orabona 4, I-70126, Bari, Italy
| | - Piero Leone
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari "Aldo Moro", via Orabona 4, I-70126, Bari, Italy
| | - Michele Galluccio
- Dipartimento DiBEST (Biologia, Ecologia, Scienze della Terra), Unità di Biochimica e Biotecnologie Molecolari, Università della Calabria, via Bucci 4c, I-87036, Arcavacata di Rende, Italy
| | - Cesare Indiveri
- Dipartimento DiBEST (Biologia, Ecologia, Scienze della Terra), Unità di Biochimica e Biotecnologie Molecolari, Università della Calabria, via Bucci 4c, I-87036, Arcavacata di Rende, Italy
| |
Collapse
|
11
|
Olsen RKJ, Koňaříková E, Giancaspero TA, Mosegaard S, Boczonadi V, Mataković L, Veauville-Merllié A, Terrile C, Schwarzmayr T, Haack TB, Auranen M, Leone P, Galluccio M, Imbard A, Gutierrez-Rios P, Palmfeldt J, Graf E, Vianey-Saban C, Oppenheim M, Schiff M, Pichard S, Rigal O, Pyle A, Chinnery PF, Konstantopoulou V, Möslinger D, Feichtinger RG, Talim B, Topaloglu H, Coskun T, Gucer S, Botta A, Pegoraro E, Malena A, Vergani L, Mazzà D, Zollino M, Ghezzi D, Acquaviva C, Tyni T, Boneh A, Meitinger T, Strom TM, Gregersen N, Mayr JA, Horvath R, Barile M, Prokisch H. Riboflavin-Responsive and -Non-responsive Mutations in FAD Synthase Cause Multiple Acyl-CoA Dehydrogenase and Combined Respiratory-Chain Deficiency. Am J Hum Genet 2016; 98:1130-1145. [PMID: 27259049 PMCID: PMC4908180 DOI: 10.1016/j.ajhg.2016.04.006] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 04/13/2016] [Indexed: 12/27/2022] Open
Abstract
Multiple acyl-CoA dehydrogenase deficiencies (MADDs) are a heterogeneous group of metabolic disorders with combined respiratory-chain deficiency and a neuromuscular phenotype. Despite recent advances in understanding the genetic basis of MADD, a number of cases remain unexplained. Here, we report clinically relevant variants in FLAD1, which encodes FAD synthase (FADS), as the cause of MADD and respiratory-chain dysfunction in nine individuals recruited from metabolic centers in six countries. In most individuals, we identified biallelic frameshift variants in the molybdopterin binding (MPTb) domain, located upstream of the FADS domain. Inasmuch as FADS is essential for cellular supply of FAD cofactors, the finding of biallelic frameshift variants was unexpected. Using RNA sequencing analysis combined with protein mass spectrometry, we discovered FLAD1 isoforms, which only encode the FADS domain. The existence of these isoforms might explain why affected individuals with biallelic FLAD1 frameshift variants still harbor substantial FADS activity. Another group of individuals with a milder phenotype responsive to riboflavin were shown to have single amino acid changes in the FADS domain. When produced in E. coli, these mutant FADS proteins resulted in impaired but detectable FADS activity; for one of the variant proteins, the addition of FAD significantly improved protein stability, arguing for a chaperone-like action similar to what has been reported in other riboflavin-responsive inborn errors of metabolism. In conclusion, our studies identify FLAD1 variants as a cause of potentially treatable inborn errors of metabolism manifesting with MADD and shed light on the mechanisms by which FADS ensures cellular FAD homeostasis.
Collapse
MESH Headings
- Adult
- Blotting, Western
- Case-Control Studies
- Cells, Cultured
- Electron Transport
- Female
- Fibroblasts/drug effects
- Fibroblasts/metabolism
- Fibroblasts/pathology
- Flavin-Adenine Dinucleotide/metabolism
- Frameshift Mutation/genetics
- Gene Expression Profiling
- Humans
- Infant
- Infant, Newborn
- Liver/drug effects
- Liver/metabolism
- Liver/pathology
- Male
- Mitochondrial Diseases/drug therapy
- Mitochondrial Diseases/genetics
- Mitochondrial Diseases/pathology
- Multiple Acyl Coenzyme A Dehydrogenase Deficiency/drug therapy
- Multiple Acyl Coenzyme A Dehydrogenase Deficiency/genetics
- Multiple Acyl Coenzyme A Dehydrogenase Deficiency/pathology
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Mutagenesis, Site-Directed
- Nucleotidyltransferases/genetics
- Protein Binding
- RNA, Messenger/genetics
- Real-Time Polymerase Chain Reaction
- Reverse Transcriptase Polymerase Chain Reaction
- Riboflavin/pharmacology
- Skin/drug effects
- Skin/metabolism
- Skin/pathology
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Vitamin B Complex/pharmacology
- Young Adult
Collapse
Affiliation(s)
- Rikke K J Olsen
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and University Hospital, 8200 Aarhus N, Denmark.
| | - Eliška Koňaříková
- Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany; Institute of Human Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Teresa A Giancaspero
- Department of Biosciences, Biotechnology, and Biopharmaceutics, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Signe Mosegaard
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and University Hospital, 8200 Aarhus N, Denmark
| | - Veronika Boczonadi
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Lavinija Mataković
- Department of Paediatrics, Paracelsus Medical University, SALK Salzburg, 5020 Salzburg, Austria
| | - Alice Veauville-Merllié
- Service Maladies Héréditaires du Métabolisme et Dépistage Néonatal, Centre de Biologie et Pathologie Est, Centre Hospitalier Universitaire Lyon, 69500 Bron, France
| | - Caterina Terrile
- Institute of Human Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Thomas Schwarzmayr
- Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany; Institute of Human Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Tobias B Haack
- Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany; Institute of Human Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Mari Auranen
- Clinical Neurosciences, Neurology, University of Helsinki and Helsinki University Hospital, 340 Helsinki, Finland
| | - Piero Leone
- Department of Biosciences, Biotechnology, and Biopharmaceutics, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Michele Galluccio
- Department DiBEST (Biology, Ecology, and Earth Sciences), University of Calabria, 87036 Arcavacata di Rende, Italy
| | - Apolline Imbard
- Biochemistry Hormonology Laboratory, Robert-Debré Hospital, 75019 Paris, France; Pharmacy Faculty, Paris Sud University, 92019 Chatenay-Malabry, France
| | - Purificacion Gutierrez-Rios
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK; Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide, 41013 Seville, Spain
| | - Johan Palmfeldt
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and University Hospital, 8200 Aarhus N, Denmark
| | - Elisabeth Graf
- Institute of Human Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Christine Vianey-Saban
- Service Maladies Héréditaires du Métabolisme et Dépistage Néonatal, Centre de Biologie et Pathologie Est, Centre Hospitalier Universitaire Lyon, 69500 Bron, France
| | - Marcus Oppenheim
- Neurometabolic Unit, National Hospital for Neurology and Neurosurgery, London WCIN 3BG, UK
| | - Manuel Schiff
- INSERM UMR 1141, Hôpital Robert Debré, 75019 Paris, France; Reference Center for Inherited Metabolic Diseases, Robert-Debré Hospital, Assistance Publique - Hôpitaux de Paris, 75019 Paris, France; Faculté de Médecine Denis Diderot, Université Paris Diderot (Paris 7), 75013 Paris, France
| | - Samia Pichard
- Reference Center for Inherited Metabolic Diseases, Robert-Debré Hospital, Assistance Publique - Hôpitaux de Paris, 75019 Paris, France
| | - Odile Rigal
- Biochemistry Hormonology Laboratory, Robert-Debré Hospital, 75019 Paris, France
| | - Angela Pyle
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Patrick F Chinnery
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK; Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge CB2 0QQ, UK
| | | | - Dorothea Möslinger
- Department of Pediatrics, Medical University of Vienna, 1090 Vienna, Austria
| | - René G Feichtinger
- Department of Paediatrics, Paracelsus Medical University, SALK Salzburg, 5020 Salzburg, Austria
| | - Beril Talim
- Pathology Unit, Department of Pediatrics, Hacettepe University Children's Hospital, 06100 Ankara, Turkey
| | - Haluk Topaloglu
- Neurology Unit, Department of Pediatrics, Hacettepe University Children's Hospital, 06100 Ankara, Turkey
| | - Turgay Coskun
- Metabolism Unit, Department of Pediatrics, Hacettepe University Children's Hospital, 06100 Ankara, Turkey
| | - Safak Gucer
- Pathology Unit, Department of Pediatrics, Hacettepe University Children's Hospital, 06100 Ankara, Turkey
| | - Annalisa Botta
- Medical Genetics Section, Department of Biomedicine and Prevention, Tor Vergata University of Rome, 00133 Rome, Italy
| | - Elena Pegoraro
- Neuromuscular Center, Department of Neurosciences, University of Padova, 35129 Padova, Italy
| | - Adriana Malena
- Neuromuscular Center, Department of Neurosciences, University of Padova, 35129 Padova, Italy
| | - Lodovica Vergani
- Neuromuscular Center, Department of Neurosciences, University of Padova, 35129 Padova, Italy
| | - Daniela Mazzà
- Italy Institute of Medical Genetics, Catholic University of Roma, 00168 Rome, Italy
| | - Marcella Zollino
- Italy Institute of Medical Genetics, Catholic University of Roma, 00168 Rome, Italy
| | - Daniele Ghezzi
- Molecular Neurogenetics Unit, Foundation IRCCS Neurological Institute C. Besta, 20126 Milan, Italy
| | - Cecile Acquaviva
- Service Maladies Héréditaires du Métabolisme et Dépistage Néonatal, Centre de Biologie et Pathologie Est, Centre Hospitalier Universitaire Lyon, 69500 Bron, France
| | - Tiina Tyni
- Department of Pediatric Neurology, Hospital for Children and Adolescence, Helsinki University Central Hospital, 280 Helsinki, Finland
| | - Avihu Boneh
- Murdoch Childrens Research Institute and University of Melbourne, Melbourne, VIC 3010, Australia
| | - Thomas Meitinger
- Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany; Institute of Human Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Tim M Strom
- Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany; Institute of Human Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Niels Gregersen
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and University Hospital, 8200 Aarhus N, Denmark
| | - Johannes A Mayr
- Department of Paediatrics, Paracelsus Medical University, SALK Salzburg, 5020 Salzburg, Austria
| | - Rita Horvath
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Maria Barile
- Department of Biosciences, Biotechnology, and Biopharmaceutics, University of Bari Aldo Moro, 70125 Bari, Italy.
| | - Holger Prokisch
- Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany; Institute of Human Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| |
Collapse
|
12
|
Giancaspero TA, Galluccio M, Miccolis A, Leone P, Eberini I, Iametti S, Indiveri C, Barile M. Human FAD synthase is a bi-functional enzyme with a FAD hydrolase activity in the molybdopterin binding domain. Biochem Biophys Res Commun 2015; 465:443-9. [PMID: 26277395 DOI: 10.1016/j.bbrc.2015.08.035] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 08/09/2015] [Indexed: 02/05/2023]
Abstract
FAD synthase (FMN:ATP adenylyl transferase, FMNAT or FADS, EC 2.7.7.2) is involved in the biochemical pathway for converting riboflavin into FAD. Human FADS exists in different isoforms. Two of these have been characterized and are localized in different subcellular compartments. hFADS2 containing 490 amino acids shows a two domain organization: the 3'-phosphoadenosine-5'-phosphosulfate (PAPS) reductase domain, that is the FAD-forming catalytic domain, and a resembling molybdopterin-binding (MPTb) domain. By a multialignment of hFADS2 with other MPTb containing proteins of various organisms from bacteria to plants, the critical residues for hydrolytic function were identified. A homology model of the MPTb domain of hFADS2 was built, using as template the solved structure of a T. acidophilum enzyme. The capacity of hFADS2 to catalyse FAD hydrolysis was revealed. The recombinant hFADS2 was able to hydrolyse added FAD in a Co(2+) and mersalyl dependent reaction. The recombinant PAPS reductase domain is not able to perform the same function. The mutant C440A catalyses the same hydrolytic function of WT with no essential requirement for mersalyl, thus indicating the involvement of C440 in the control of hydrolysis switch. The enzyme C440A is also able to catalyse hydrolysis of FAD bound to the PAPS reductase domain, which is quantitatively converted into FMN.
Collapse
Affiliation(s)
- Teresa Anna Giancaspero
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari "A. Moro", via Orabona 4, I-70126, Bari, Italy.
| | - Michele Galluccio
- Dipartimento DiBEST, Biologia, Ecologia, Scienze della Terra, Unità di Biochimica e Biotecnologie Molecolari, Università della Calabria, via Bucci 4c, I-87036, Arcavacata di Rende, Italy.
| | - Angelica Miccolis
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari "A. Moro", via Orabona 4, I-70126, Bari, Italy.
| | - Piero Leone
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari "A. Moro", via Orabona 4, I-70126, Bari, Italy.
| | - Ivano Eberini
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, via Balzaretti 9, I-20133, Milano, Italy.
| | - Stefania Iametti
- Dipartimento di Scienze per gli Alimenti, la Nutrizione e l'Ambiente, Università degli Studi di Milano, via Celoria 2, I-20133, Milano, Italy.
| | - Cesare Indiveri
- Dipartimento DiBEST, Biologia, Ecologia, Scienze della Terra, Unità di Biochimica e Biotecnologie Molecolari, Università della Calabria, via Bucci 4c, I-87036, Arcavacata di Rende, Italy.
| | - Maria Barile
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari "A. Moro", via Orabona 4, I-70126, Bari, Italy.
| |
Collapse
|
13
|
Margittai É, Enyedi B, Csala M, Geiszt M, Bánhegyi G. Composition of the redox environment of the endoplasmic reticulum and sources of hydrogen peroxide. Free Radic Biol Med 2015; 83:331-40. [PMID: 25678412 DOI: 10.1016/j.freeradbiomed.2015.01.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 01/30/2015] [Accepted: 01/31/2015] [Indexed: 12/22/2022]
Abstract
The endoplasmic reticulum (ER) is a metabolically active organelle, which has a central role in proteostasis by translating, modifying, folding, and occasionally degrading secretory and membrane proteins. The lumen of the ER represents a separate compartment of the eukaryotic cell, with a characteristic proteome and metabolome. Although the redox metabolome and proteome of the compartment have not been holistically explored, it is evident that proper redox conditions are necessary for the functioning of many luminal pathways. These redox conditions are defined by local oxidoreductases and the membrane transport of electron donors and acceptors. The main electron carriers of the compartment are identical with those of the other organelles: glutathione, pyridine and flavin nucleotides, ascorbate, and others. However, their composition, concentration, and redox state in the ER lumen can be different from those observed in other compartments. The terminal oxidases of oxidative protein folding generate and maintain an "oxidative environment" by oxidizing protein thiols and producing hydrogen peroxide. ER-specific mechanisms reutilize hydrogen peroxide as an electron acceptor of oxidative folding. These mechanisms, together with membrane and kinetic barriers, guarantee that redox systems in the reduced or oxidized state can be present simultaneously in the lumen. The present knowledge on the in vivo conditions of ER redox is rather limited; development of new genetically encoded targetable sensors for the measurement of the luminal state of redox systems other than thiol/disulfide will contribute to a better understanding of ER redox homeostasis.
Collapse
Affiliation(s)
- Éva Margittai
- Institute of Human Physiology and Clinical Experimental Research, Semmelweis University, Budapest 1444, Hungary
| | - Balázs Enyedi
- Department of Physiology, Semmelweis University, Budapest 1444, Hungary
| | - Miklós Csala
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest 1444, Hungary
| | - Miklós Geiszt
- Department of Physiology, Semmelweis University, Budapest 1444, Hungary; "Lendület" Peroxidase Enzyme Research Group of Semmelweis University and the Hungarian Academy of Sciences, Semmelweis University, Budapest 1444, Hungary
| | - Gábor Bánhegyi
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest 1444, Hungary.
| |
Collapse
|
14
|
Giancaspero TA, Colella M, Brizio C, Difonzo G, Fiorino GM, Leone P, Brandsch R, Bonomi F, Iametti S, Barile M. Remaining challenges in cellular flavin cofactor homeostasis and flavoprotein biogenesis. Front Chem 2015; 3:30. [PMID: 25954742 PMCID: PMC4406087 DOI: 10.3389/fchem.2015.00030] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 04/05/2015] [Indexed: 12/27/2022] Open
Abstract
The primary role of the water-soluble vitamin B2 (riboflavin) in cell biology is connected with its conversion into FMN and FAD, the cofactors of a large number of dehydrogenases, oxidases and reductases involved in a broad spectrum of biological activities, among which energetic metabolism and chromatin remodeling. Subcellular localisation of FAD synthase (EC 2.7.7.2, FADS), the second enzyme in the FAD forming pathway, is addressed here in HepG2 cells by confocal microscopy, in the frame of its relationships with kinetics of FAD synthesis and delivery to client apo-flavoproteins. FAD synthesis catalyzed by recombinant isoform 2 of FADS occurs via an ordered bi-bi mechanism in which ATP binds prior to FMN, and pyrophosphate is released before FAD. Spectrophotometric continuous assays of the reconstitution rate of apo-D-aminoacid oxidase with its cofactor, allowed us to propose that besides its FAD synthesizing activity, hFADS is able to operate as a FAD “chaperone.” The physical interaction between FAD forming enzyme and its clients was further confirmed by dot blot and immunoprecipitation experiments carried out testing as a client either a nuclear lysine-specific demethylase 1 (LSD1) or a mitochondrial dimethylglycine dehydrogenase (Me2GlyDH, EC 1.5.8.4). Both enzymes carry out similar reactions of oxidative demethylation, in which tetrahydrofolate is converted into 5,10-methylene-tetrahydrofolate. A direct transfer of the cofactor from hFADS2 to apo-dimethyl glycine dehydrogenase was also demonstrated. Thus, FAD synthesis and delivery to these enzymes are crucial processes for bioenergetics and nutri-epigenetics of liver cells.
Collapse
Affiliation(s)
- Teresa A Giancaspero
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari Aldo Moro Bari, Italy
| | - Matilde Colella
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari Aldo Moro Bari, Italy
| | - Carmen Brizio
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari Aldo Moro Bari, Italy
| | - Graziana Difonzo
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari Aldo Moro Bari, Italy
| | - Giuseppina M Fiorino
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari Aldo Moro Bari, Italy
| | - Piero Leone
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari Aldo Moro Bari, Italy
| | - Roderich Brandsch
- Institut für Biochemie und Molekularbiologie, Universität Freiburg Freiburg, Germany
| | - Francesco Bonomi
- Dipartimento di Scienze per gli Alimenti, la Nutrizione e l'Ambiente, Università degli Studi di Milano Milano, Italy
| | - Stefania Iametti
- Dipartimento di Scienze per gli Alimenti, la Nutrizione e l'Ambiente, Università degli Studi di Milano Milano, Italy
| | - Maria Barile
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari Aldo Moro Bari, Italy ; Dipartimento di Scienze della Vita, Istituto di Biomembrane e Bioenergetica, CNR Bari, Italy
| |
Collapse
|
15
|
Tonazzi A, Giangregorio N, Console L, Scalise M, La Russa D, Notaristefano C, Brunelli E, Barca D, Indiveri C. Mitochondrial carnitine/acylcarnitine transporter, a novel target of mercury toxicity. Chem Res Toxicol 2015; 28:1015-22. [PMID: 25849418 DOI: 10.1021/acs.chemrestox.5b00050] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The effect of Hg(2+) and CH3Hg(+) on the mitochondrial carnitine/acylcarnitine transporter (CACT) has been studied on the recombinant protein and on the CACT extracted from HeLa cells or Zebrafish and reconstituted in proteoliposomes. Transport was abolished upon treatment of the recombinant CACT in proteoliposomes by Hg(2+) or CH3Hg(+). Inhibition was reversed by the SH reducing agent 1,4-dithioerythritol, GSH, and N-acetylcysteine. IC50 for Hg(2+) and CH3Hg(+) of 90 nM and 137 nM, respectively, were measured by dose-response analyses. Inhibition was abolished in the C-less CACT mutant. Strong reduction of inhibition by both reagents was observed in the C136A and some reduction in the C155A mutants. Inhibition similar to that of the WT was observed in the C23V/C58V/C89S/C155V/C283S mutant, containing only C136. Optimal inhibition by Hg(2+)was found in the four replacement mutants C23V/C58V/C89S/C283S containing both C136 and C155 indicating cross-reaction of Hg(2+) with the two Cys residues. Inhibition kinetic analysis showed mixed inhibition by Hg(2+) or competitive inhibition by CH3Hg(+). HeLa cells or Zebrafish were treated with the more potent inhibitor. Ten micromolar HgCl2 caused clear impairment of viability of HeLa cells. The transport assay in proteoliposomes with CACT extracted from treated cells showed that the transporter was inactivated and that DTE rescued the activity. Nearly identical results were observed with Zebrafish upon extraction of the CACT from the liver of the treated animals that, indeed, showed accumulation of the mercurial compound.
Collapse
Affiliation(s)
- Annamaria Tonazzi
- †CNR Institute of Biomembranes and Bioenergetics, via Amendola 165/A, 70126 Bari, Italy.,‡Department of Bioscience, Biotechnology and Biopharmaceutics, University of Bari, Bari, Italy
| | - Nicola Giangregorio
- †CNR Institute of Biomembranes and Bioenergetics, via Amendola 165/A, 70126 Bari, Italy.,‡Department of Bioscience, Biotechnology and Biopharmaceutics, University of Bari, Bari, Italy
| | - Lara Console
- §Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via Bucci 4C, 87036 Arcavacata di Rende, Italy
| | - Mariafrancesca Scalise
- §Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via Bucci 4C, 87036 Arcavacata di Rende, Italy
| | - Daniele La Russa
- §Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via Bucci 4C, 87036 Arcavacata di Rende, Italy
| | - Caterina Notaristefano
- ‡Department of Bioscience, Biotechnology and Biopharmaceutics, University of Bari, Bari, Italy
| | - Elvira Brunelli
- §Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via Bucci 4C, 87036 Arcavacata di Rende, Italy
| | - Donatella Barca
- §Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via Bucci 4C, 87036 Arcavacata di Rende, Italy
| | - Cesare Indiveri
- †CNR Institute of Biomembranes and Bioenergetics, via Amendola 165/A, 70126 Bari, Italy.,§Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via Bucci 4C, 87036 Arcavacata di Rende, Italy
| |
Collapse
|