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Arrault C, Monneau YR, Martin M, Cantrelle FX, Boll E, Chirot F, Comby Zerbino C, Walker O, Hologne M. The battle for silver binding: How the interplay between the SilE, SilF, and SilB proteins contributes to the silver efflux pump mechanism. J Biol Chem 2023; 299:105004. [PMID: 37394004 PMCID: PMC10407283 DOI: 10.1016/j.jbc.2023.105004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 06/27/2023] [Accepted: 06/28/2023] [Indexed: 07/04/2023] Open
Abstract
The resistance of gram-negative bacteria to silver ions is mediated by a silver efflux pump, which mainly relies on a tripartite efflux complex SilCBA, a metallochaperone SilF and an intrinsically disordered protein SilE. However, the precise mechanism by which silver ions are extruded from the cell and the different roles of SilB, SilF, and SilE remain poorly understood. To address these questions, we employed nuclear magnetic resonance and mass spectrometry to investigate the interplay between these proteins. We first solved the solution structures of SilF in its free and Ag+-bound forms, and we demonstrated that SilB exhibits two silver binding sites in its N and C termini. Conversely to the homologous Cus system, we determined that SilF and SilB interact without the presence of silver ions and that the rate of silver dissociation is eight times faster when SilF is bound to SilB, indicating the formation of a SilF-Ag-SilB intermediate complex. Finally, we have shown that SilE does not bind to either SilF or SilB, regardless of the presence or absence of silver ions, further corroborating that it merely acts as a regulator that prevents the cell from being overloaded with silver. Collectively, we have provided further insights into protein interactions within the sil system that contribute to bacterial resistance to silver ions.
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Affiliation(s)
- Cyrielle Arrault
- Université de Lyon, CNRS, UCB Lyon1, Institut des Sciences Analytiques, UMR5280, Villeurbanne, France
| | - Yoan Rocky Monneau
- Université de Lyon, CNRS, UCB Lyon1, Institut des Sciences Analytiques, UMR5280, Villeurbanne, France; Department of Structural Biology, St Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Marie Martin
- Université de Lyon, CNRS, UCB Lyon1, Institut des Sciences Analytiques, UMR5280, Villeurbanne, France
| | - François-Xavier Cantrelle
- Université de Lille, CNRS, UMR8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Emmanuelle Boll
- Université de Lille, CNRS, UMR8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Fabien Chirot
- Univ Lyon 1, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, UMR5306, Cité Lyonnaise de l'Environnement et de l'Analyse, Villeurbanne, France
| | - Clothilde Comby Zerbino
- Univ Lyon 1, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, UMR5306, Cité Lyonnaise de l'Environnement et de l'Analyse, Villeurbanne, France
| | - Olivier Walker
- Université de Lyon, CNRS, UCB Lyon1, Institut des Sciences Analytiques, UMR5280, Villeurbanne, France
| | - Maggy Hologne
- Université de Lyon, CNRS, UCB Lyon1, Institut des Sciences Analytiques, UMR5280, Villeurbanne, France.
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2
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Hemmann JL, Keller P, Hemmerle L, Vonderach T, Ochsner AM, Bortfeld-Miller M, Günther D, Vorholt JA. Lanpepsy is a novel lanthanide-binding protein involved in the lanthanide response of the obligate methylotroph Methylobacillus flagellatus. J Biol Chem 2023; 299:102940. [PMID: 36702252 PMCID: PMC9988556 DOI: 10.1016/j.jbc.2023.102940] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 01/19/2023] [Accepted: 01/20/2023] [Indexed: 01/24/2023] Open
Abstract
Lanthanides were recently discovered as metals required in the active site of certain methanol dehydrogenases. Since then, the characterization of the lanthanome, that is, proteins involved in sensing, uptake, and utilization of lanthanides, has become an active field of research. Initial exploration of the response to lanthanides in methylotrophs has revealed that the lanthanome is not conserved and that multiple mechanisms for lanthanide utilization must exist. Here, we investigated the lanthanome in the obligate model methylotroph Methylobacillus flagellatus. We used a proteomic approach to analyze differentially regulated proteins in the presence of lanthanum. While multiple known proteins showed induction upon growth in the presence of lanthanum (Xox proteins, TonB-dependent receptor), we also identified several novel proteins not previously associated with lanthanide utilization. Among these was Mfla_0908, a periplasmic 19 kDa protein without functional annotation. The protein comprises two characteristic PepSY domains, which is why we termed the protein lanpepsy (LanP). Based on bioinformatic analysis, we speculated that LanP could be involved in lanthanide binding. Using dye competition assays, quantification of protein-bound lanthanides by inductively coupled plasma mass spectrometry, as well as isothermal titration calorimetry, we demonstrated the presence of multiple lanthanide binding sites that showed selectivity over the chemically similar calcium ion. LanP thus represents the first member of the PepSY family that binds lanthanides. Although the physiological role of LanP is still unclear, its identification is of interest for applications toward the sustainable purification and separation of rare-earth elements.
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Affiliation(s)
- Jethro L Hemmann
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland.
| | - Philipp Keller
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Lucas Hemmerle
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Thomas Vonderach
- Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - Andrea M Ochsner
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland
| | | | - Detlef Günther
- Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - Julia A Vorholt
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland.
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3
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Damle MS, Singh AN, Peters SC, Szalai VA, Fisher OS. The YcnI protein from Bacillus subtilis contains a copper-binding domain. J Biol Chem 2021; 297:101078. [PMID: 34400169 PMCID: PMC8424229 DOI: 10.1016/j.jbc.2021.101078] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/06/2021] [Accepted: 08/11/2021] [Indexed: 11/26/2022] Open
Abstract
Bacteria require a precise balance of copper ions to ensure that essential cuproproteins are fully metalated while also avoiding copper-induced toxicity. The Gram-positive bacterium Bacillus subtilis maintains appropriate copper homeostasis in part through the ycn operon. The ycn operon comprises genes encoding three proteins: the putative copper importer YcnJ, the copper-dependent transcriptional repressor YcnK, and the uncharacterized Domain of Unknown Function 1775 (DUF1775) containing YcnI. DUF1775 domains are found across bacterial phylogeny, and bioinformatics analyses indicate that they frequently neighbor domains implicated in copper homeostasis and transport. Here, we investigated whether YcnI can interact with copper and, using electron paramagnetic resonance and inductively coupled plasma-MS, found that this protein can bind a single Cu(II) ion. We determine the structure of both the apo and copper-bound forms of the protein by X-ray crystallography, uncovering a copper-binding site featuring a unique monohistidine brace ligand set that is highly conserved among DUF1775 domains. These data suggest a possible role for YcnI as a copper chaperone and that DUF1775 domains in other bacterial species may also function in copper homeostasis.
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Affiliation(s)
- Madhura S Damle
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania, USA
| | - Aarshi N Singh
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania, USA
| | - Stephen C Peters
- Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, Pennsylvania, USA
| | - Veronika A Szalai
- Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland, USA
| | - Oriana S Fisher
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania, USA.
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4
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Ho K, Bradshaw N. A conserved allosteric element controls specificity and activity of functionally divergent PP2C phosphatases from Bacillus subtilis. J Biol Chem 2021; 296:100518. [PMID: 33684446 DOI: 10.1016/j.jbc.2021.100518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 03/01/2021] [Accepted: 03/04/2021] [Indexed: 01/08/2023] Open
Abstract
Reversible phosphorylation relies on highly regulated kinases and phosphatases that target specific substrates to control diverse cellular processes. Here, we address how protein phosphatase activity is directed to the correct substrates under the correct conditions. The serine/threonine phosphatase SpoIIE from Bacillus subtilis, a member of the widespread protein phosphatase 2C (PP2C) family of phosphatases, is activated by movement of a conserved α-helical element in the phosphatase domain to create the binding site for the metal cofactor. We hypothesized that this conformational switch could provide a general mechanism for control of diverse members of the PP2C family of phosphatases. The B. subtilis phosphatase RsbU responds to different signals, acts on a different substrates, and produces a more graded response than SpoIIE. Using an unbiased genetic screen, we isolated mutants in the α-helical switch region of RsbU that are constitutively active, indicating conservation of the switch mechanism. Using phosphatase activity assays with phosphoprotein substrates, we found that both phosphatases integrate substrate recognition with activating signals to control metal-cofactor binding and substrate dephosphorylation. This integrated control provides a mechanism for PP2C family of phosphatases to produce specific responses by acting on the correct substrates, under the appropriate conditions.
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5
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Ando T, Jongruja N, Okumura N, Morikawa K, Kanaya S, Takao T. Identification of the ternary complex of ribonuclease HI:RNA/DNA hybrid:metal ions by ESI mass spectrometry. J Biol Chem 2021; 296:100462. [PMID: 33639158 PMCID: PMC8042393 DOI: 10.1016/j.jbc.2021.100462] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 02/14/2021] [Accepted: 02/23/2021] [Indexed: 12/17/2022] Open
Abstract
Ribonuclease HI, an endoribonuclease, catalyzes the hydrolysis of the RNA strand of an RNA/DNA hybrid and requires divalent metal ions for its enzymatic activity. However, the mechanistic details of the activity of ribonuclease HI and its interaction with divalent metal ions remain unclear. In this study, we performed real-time monitoring of the enzyme–substrate complex in the presence of divalent metal ions (Mn2+ or Zn2+) using electrospray ionization–mass spectrometry (ESI-MS). The findings provide clear evidence that the enzymatic activity of the ternary complex requires the binding of two divalent metal ions. The Zn2+ ions bind to both the enzyme itself and the enzyme:substrate complex more strongly than Mn2+ ions, and gives, in part, the ternary complex, [RNase HI:nicked RNA/DNA hybrid:2Zn2+], suggesting that the ternary complex is retained, even after the hydrolysis of the substrate. The collective results presented herein shed new light on the essential role of divalent metal ions in the activity of ribonuclease HI and demonstrate how Zn2+ ions confer inhibitory properties on the activity of this enzyme by forming a highly stable complex with the substrate.
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Affiliation(s)
- Tomoshige Ando
- Institute for Protein Research, Osaka University, Osaka, Japan
| | | | - Nobuaki Okumura
- Institute for Protein Research, Osaka University, Osaka, Japan
| | - Kosuke Morikawa
- Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | | | - Toshifumi Takao
- Institute for Protein Research, Osaka University, Osaka, Japan.
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6
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Raj R, Nadig S, Patel T, Gopal B. Structural and biochemical characteristics of two Staphylococcus epidermidis RNase J paralogs RNase J1 and RNase J2. J Biol Chem 2020; 295:16863-16876. [PMID: 32994223 PMCID: PMC7864078 DOI: 10.1074/jbc.ra120.014876] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 09/21/2020] [Indexed: 11/06/2022] Open
Abstract
RNase J enzymes are metallohydrolases that are involved in RNA maturation and RNA recycling, govern gene expression in bacteria, and catalyze both exonuclease and endonuclease activity. The catalytic activity of RNase J is regulated by multiple mechanisms which include oligomerization, conformational changes to aid substrate recognition, and the metal cofactor at the active site. However, little is known of how RNase J paralogs differ in expression and activity. Here we describe structural and biochemical features of two Staphylococcus epidermidis RNase J paralogs, RNase J1 and RNase J2. RNase J1 is a homodimer with exonuclease activity aided by two metal cofactors at the active site. RNase J2, on the other hand, has endonuclease activity and one metal ion at the active site and is predominantly a monomer. We note that the expression levels of these enzymes vary across Staphylococcal strains. Together, these observations suggest that multiple interacting RNase J paralogs could provide a strategy for functional improvisation utilizing differences in intracellular concentration, quaternary structure, and distinct active site architecture despite overall structural similarity.
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Affiliation(s)
- Rishi Raj
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Savitha Nadig
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Twinkal Patel
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
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7
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Németh B, Land H, Magnuson A, Hofer A, Berggren G. The maturase HydF enables [FeFe] hydrogenase assembly via transient, cofactor-dependent interactions. J Biol Chem 2020; 295:11891-11901. [PMID: 32620553 PMCID: PMC7450098 DOI: 10.1074/jbc.ra119.011419] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 06/25/2020] [Indexed: 12/24/2022] Open
Abstract
[FeFe] hydrogenases have attracted extensive attention in the field of renewable energy research because of their remarkable efficiency for H2 gas production. H2 formation is catalyzed by a biologically unique hexanuclear iron cofactor denoted the H-cluster. The assembly of this cofactor requires a dedicated maturation machinery including HydF, a multidomain [4Fe4S] cluster protein with GTPase activity. HydF is responsible for harboring and delivering a precatalyst to the apo-hydrogenase, but the details of this process are not well understood. Here, we utilize gas-phase electrophoretic macromolecule analysis to show that a HydF dimer forms a transient interaction complex with the hydrogenase and that the formation of this complex depends on the cofactor content on HydF. Moreover, Fourier transform infrared, electron paramagnetic resonance, and UV-visible spectroscopy studies of mutants of HydF show that the isolated iron-sulfur cluster domain retains the capacity for binding the precatalyst in a reversible fashion and is capable of activating apo-hydrogenase in in vitro assays. These results demonstrate the central role of the iron-sulfur cluster domain of HydF in the final stages of H-cluster assembly, i.e. in binding and delivering the precatalyst.
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Affiliation(s)
- Brigitta Németh
- Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Henrik Land
- Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Ann Magnuson
- Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Anders Hofer
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Gustav Berggren
- Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala, Sweden
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8
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Nam D, Matsumoto Y, Uchida T, O'Brian MR, Ishimori K. Mechanistic insights into heme-mediated transcriptional regulation via a bacterial manganese-binding iron regulator, iron response regulator (Irr). J Biol Chem 2020; 295:11316-11325. [PMID: 32554810 DOI: 10.1074/jbc.ra119.011855] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 06/15/2020] [Indexed: 11/06/2022] Open
Abstract
The transcription factor iron response regulator (Irr) is a key regulator of iron homeostasis in the nitrogen-fixating bacterium Bradyrhizobium japonicum Irr acts by binding to target genes, including the iron control element (ICE), and is degraded in response to heme binding. Here, we examined this binding activity using fluorescence anisotropy with a 6-carboxyfluorescein-labeled ICE-like oligomer (FAM-ICE). In the presence of Mn2+, Irr addition increased the fluorescence anisotropy, corresponding to formation of the Irr-ICE complex. The addition of EDTA to the Irr-ICE complex reduced fluorescence anisotropy, but fluorescence was recovered after Mn2+ addition, indicating that Mn2+ binding is a prerequisite for complex formation. Binding activity toward ICE was lost upon introduction of substitutions in a His-cluster region of Irr, revealing that Mn2+ binds to this region. We observed that the His-cluster region is also the heme binding site; results from fluorescence anisotropy and electrophoretic mobility shift analyses disclosed that the addition of a half-equivalent of heme dissociates Irr from ICE, likely because of Mn2+ release due to heme binding. We hypothesized that heme binding to another heme binding site, Cys-29, would also inhibit the formation of the Irr-ICE complex because it is proximal to the ICE binding site, which was supported by the loss of ICE binding activity in a Cys-29-mutated Irr. These results indicate that Irr requires Mn2+ binding to form the Irr-ICE complex and that the addition of heme dissociates Irr from ICE by replacing Mn2+ with heme or by heme binding to Cys-29.
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Affiliation(s)
- Dayeon Nam
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Japan
| | - Yuki Matsumoto
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Japan
| | - Takeshi Uchida
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Japan.,Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Japan
| | - Mark R O'Brian
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Koichiro Ishimori
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Japan .,Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Japan
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9
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Pederick JL, Thompson AP, Bell SG, Bruning JB. d-Alanine-d-alanine ligase as a model for the activation of ATP-grasp enzymes by monovalent cations. J Biol Chem 2020; 295:7894-7904. [PMID: 32335509 DOI: 10.1074/jbc.ra120.012936] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 04/23/2020] [Indexed: 12/18/2022] Open
Abstract
The ATP-grasp superfamily of enzymes shares an atypical nucleotide-binding site known as the ATP-grasp fold. These enzymes are involved in many biological pathways in all domains of life. One ATP-grasp enzyme, d-alanine-d-alanine ligase (Ddl), catalyzes ATP-dependent formation of the d-alanyl-d-alanine dipeptide essential for bacterial cell wall biosynthesis and is therefore an important antibiotic drug target. Ddl is activated by the monovalent cation (MVC) K+, but despite its clinical relevance and decades of research, how this activation occurs has not been elucidated. We demonstrate here that activating MVCs bind adjacent to the active site of Ddl from Thermus thermophilus and used a combined biochemical and structural approach to characterize MVC activation. We found that TtDdl is a type II MVC-activated enzyme, retaining activity in the absence of MVCs. However, the efficiency of TtDdl increased ∼20-fold in the presence of activating MVCs, and it was maximally activated by K+ and Rb+ ions. A strict dependence on ionic radius of the MVC was observed, with Li+ and Na+ providing little to no TtDdl activation. To understand the mechanism of MVC activation, we solved crystal structures of TtDdl representing distinct catalytic stages in complex with K+, Rb+, or Cs+ Comparison of these structures with apo TtDdl revealed no evident conformational change on MVC binding. Of note, the identified MVC binding site is structurally conserved within the ATP-grasp superfamily. We propose that MVCs activate Ddl by altering the charge distribution of its active site. These findings provide insight into the catalytic mechanism of ATP-grasp enzymes.
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Affiliation(s)
- Jordan L Pederick
- Institute for Photonics and Advanced Sensing, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, Australia.,Department of Molecular and Cellular Biology, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, Australia
| | - Andrew P Thompson
- Department of Molecular and Cellular Biology, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, Australia
| | - Stephen G Bell
- Department of Chemistry, The University of Adelaide, Adelaide, South Australia, Australia
| | - John B Bruning
- Institute for Photonics and Advanced Sensing, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, Australia .,Department of Molecular and Cellular Biology, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, Australia
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10
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Abstract
Many transition metals are essential trace nutrients for living organisms, but they are also cytotoxic in high concentrations. Bacteria maintain the delicate balance between metal starvation and toxicity through a complex network of metal homeostasis pathways. These systems are coordinated by the activities of metal-responsive transcription factors-also known as metal-sensor proteins or metalloregulators-that are tuned to sense the bioavailability of specific metals in the cell in order to regulate the expression of genes encoding proteins that contribute to metal homeostasis. Metal binding to a metalloregulator allosterically influences its ability to bind specific DNA sequences through a variety of intricate mechanisms that lie on a continuum between large conformational changes and subtle changes in internal dynamics. This review summarizes recent advances in our understanding of how metal sensor proteins respond to intracellular metal concentrations. In particular, we highlight the allosteric mechanisms used for metal-responsive regulation of several prokaryotic single-component metalloregulators, and we briefly discuss current open questions of how metalloregulators function in bacterial cells. Understanding the regulation and function of metal-responsive transcription factors is a fundamental aspect of metallobiochemistry and is important for gaining insights into bacterial growth and virulence.
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Affiliation(s)
- Karina A Baksh
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Deborah B Zamble
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
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11
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Gupta S, Merriman C, Petzold CJ, Ralston CY, Fu D. Water molecules mediate zinc mobility in the bacterial zinc diffusion channel ZIPB. J Biol Chem 2019; 294:13327-13335. [PMID: 31320477 DOI: 10.1074/jbc.ra119.009239] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 07/17/2019] [Indexed: 11/06/2022] Open
Abstract
Regulated ion diffusion across biological membranes is vital for cell function. In a nanoscale ion channel, the active role of discrete water molecules in modulating hydrodynamic behaviors of individual ions is poorly understood because of the technical challenge of tracking water molecules through the channel. Here we report the results of a hydroxyl radical footprinting analysis of the zinc-selective channel ZIPB from the Gram-negative bacterium, Bordetella bronchiseptica Irradiating ZIPB by microsecond X-ray pulses activated water molecules to form covalent hydroxyl radical adducts at nearby residues, which were identified by bottom-up proteomics to detect residues that interact either with zinc or water in response to zinc binding. We found a series of residues exhibiting reciprocal changes in water accessibility attributed to alternating zinc and water binding. Mapping these residues to the previously reported crystal structure of ZIPB, we identified a water-reactive pathway that superimposed on a zinc translocation pathway consisting of two binuclear metal centers and an interim zinc-binding site. The cotranslocation of zinc and water suggested that pore-lining residues undergo a mode switch between zinc coordination and water binding to confer zinc mobility. The unprecedented details of water-mediated zinc transport identified here highlight an essential role of solvated waters in driving zinc coordination dynamics and transmembrane crossing.
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Affiliation(s)
- Sayan Gupta
- Berkeley Center for Structural Biology, Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Chengfeng Merriman
- Department of Physiology, Johns Hopkins School of Medicine, Baltimore, Maryland 21205
| | - Christopher J Petzold
- Biological Systems Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720; Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Corie Y Ralston
- Berkeley Center for Structural Biology, Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Dax Fu
- Department of Physiology, Johns Hopkins School of Medicine, Baltimore, Maryland 21205.
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12
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Heidemann JL, Neumann P, Dickmanns A, Ficner R. Crystal structures of the c-di-AMP-synthesizing enzyme CdaA. J Biol Chem 2019; 294:10463-10470. [PMID: 31118276 DOI: 10.1074/jbc.ra119.009246] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Indexed: 11/06/2022] Open
Abstract
Cyclic di-AMP (c-di-AMP) is the only second messenger known to be essential for bacterial growth. It has been found mainly in Gram-positive bacteria, including pathogenic bacteria like Listeria monocytogenes CdaA is the sole diadenylate cyclase in L. monocytogenes, making this enzyme an attractive target for the development of novel antibiotic compounds. Here we report crystal structures of CdaA from L. monocytogenes in the apo state, in the post-catalytic state with bound c-di-AMP and catalytic Co2+ ions, as well as in a complex with AMP. These structures reveal the flexibility of a tyrosine side chain involved in locking the adenine ring after ATP binding. The essential role of this tyrosine was confirmed by mutation to Ala, leading to drastic loss of enzymatic activity.
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Affiliation(s)
- Jana L Heidemann
- From the Department of Molecular Structural Biology, Institute for Microbiology and Genetics, Göttingen Center for Molecular Biosciences, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Piotr Neumann
- From the Department of Molecular Structural Biology, Institute for Microbiology and Genetics, Göttingen Center for Molecular Biosciences, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Achim Dickmanns
- From the Department of Molecular Structural Biology, Institute for Microbiology and Genetics, Göttingen Center for Molecular Biosciences, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Ralf Ficner
- From the Department of Molecular Structural Biology, Institute for Microbiology and Genetics, Göttingen Center for Molecular Biosciences, Georg-August-University Göttingen, 37077 Göttingen, Germany
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13
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Holm T, Kopicki JD, Busch C, Olschewski S, Rosenthal M, Uetrecht C, Günther S, Reindl S. Biochemical and structural studies reveal differences and commonalities among cap-snatching endonucleases from segmented negative-strand RNA viruses. J Biol Chem 2018; 293:19686-19698. [PMID: 30348898 PMCID: PMC6314124 DOI: 10.1074/jbc.ra118.004373] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 10/20/2018] [Indexed: 12/22/2022] Open
Abstract
Viruses rely on many host cell processes, including the cellular transcription machinery. Segmented negative-strand RNA viruses (sNSV) in particular cannot synthesize the 5'-cap structure for their mRNA but cleave off cellular caps and use the resulting oligonucleotides as primers for their transcription. This cap-snatching mechanism, involving a viral cap-binding site and RNA endonuclease, is both virus-specific and essential for viral proliferation and therefore represents an attractive drug target. Here, we present biochemical and structural results on the putative cap-snatching endonuclease of Crimean-Congo hemorrhagic fever virus (CCHFV), a highly pathogenic bunyavirus belonging to the Nairoviridae family, and of two additional nairoviruses, Erve virus (EREV) and Nairobi sheep disease virus (NSDV). Our findings are presented in the context of other cap-snatching endonucleases, such as the enzymatically active endonuclease from Rift Valley fever virus (RVFV), from Arenaviridae and Bunyavirales, belonging to the His- and His+ endonucleases, respectively, according to the absence or presence of a metal ion-coordinating histidine in the active site. Mutational and metal-binding experiments revealed the presence of only acidic metal-coordinating residues in the active site of the CCHFV domain and a unique active-site conformation that was intermediate between those of His+ and His- endonucleases. On the basis of small-angle X-ray scattering (SAXS) and homology modeling results, we propose a protein topology for the CCHFV domain that, despite its larger size, has a structure overall similar to those of related endonucleases. These results suggest structural and functional conservation of the cap-snatching mechanism among sNSVs.
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Affiliation(s)
- Tobias Holm
- From the Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, 20359 Hamburg, Germany
| | - Janine-Denise Kopicki
- the Heinrich Pette Institute, Leibniz Institute for Experimental Virology, 20251 Hamburg, Germany, and
| | - Carola Busch
- From the Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, 20359 Hamburg, Germany
| | - Silke Olschewski
- From the Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, 20359 Hamburg, Germany
| | - Maria Rosenthal
- From the Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, 20359 Hamburg, Germany
| | - Charlotte Uetrecht
- the Heinrich Pette Institute, Leibniz Institute for Experimental Virology, 20251 Hamburg, Germany, and
- the European XFEL GmbH, 22869 Schenefeld, Germany
| | - Stephan Günther
- From the Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, 20359 Hamburg, Germany
| | - Sophia Reindl
- From the Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, 20359 Hamburg, Germany,
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14
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Loderer C, Jonna VR, Crona M, Rozman Grinberg I, Sahlin M, Hofer A, Lundin D, Sjöberg BM. A unique cysteine-rich zinc finger domain present in a majority of class II ribonucleotide reductases mediates catalytic turnover. J Biol Chem 2017; 292:19044-19054. [PMID: 28972190 PMCID: PMC5704485 DOI: 10.1074/jbc.m117.806331] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 09/28/2017] [Indexed: 12/04/2022] Open
Abstract
Ribonucleotide reductases (RNRs) catalyze the reduction of ribonucleotides to the corresponding deoxyribonucleotides, used in DNA synthesis and repair. Two different mechanisms help deliver the required electrons to the RNR active site. Formate can be used as reductant directly in the active site, or glutaredoxins or thioredoxins reduce a C-terminal cysteine pair, which then delivers the electrons to the active site. Here, we characterized a novel cysteine-rich C-terminal domain (CRD), which is present in most class II RNRs found in microbes. The NrdJd-type RNR from the bacterium Stackebrandtia nassauensis was used as a model enzyme. We show that the CRD is involved in both higher oligomeric state formation and electron transfer to the active site. The CRD-dependent formation of high oligomers, such as tetramers and hexamers, was induced by addition of dATP or dGTP, but not of dTTP or dCTP. The electron transfer was mediated by an array of six cysteine residues at the very C-terminal end, which also coordinated a zinc atom. The electron transfer can also occur between subunits, depending on the enzyme's oligomeric state. An investigation of the native reductant of the system revealed no interaction with glutaredoxins or thioredoxins, indicating that this class II RNR uses a different electron source. Our results indicate that the CRD has a crucial role in catalytic turnover and a potentially new terminal reduction mechanism and suggest that the CRD is important for the activities of many class II RNRs.
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Affiliation(s)
- Christoph Loderer
- From the Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden and
| | | | - Mikael Crona
- From the Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden and
| | - Inna Rozman Grinberg
- From the Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden and
| | - Margareta Sahlin
- From the Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden and
| | - Anders Hofer
- the Department of Medical Biochemistry, Umeå University, SE-901 87 Umeå, Sweden
| | - Daniel Lundin
- From the Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden and
| | - Britt-Marie Sjöberg
- From the Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden and
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15
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Tatsumi D, Nanatani K, Koike Y, Kamagata K, Takahashi S, Konno A, Furuta T, Sakurai M, Uozumi N. Probing native metal ion association sites through quenching of fluorophores in the nucleotide-binding domains of the ABC transporter MsbA. Biochem J 2017; 474:1993-2007. [PMID: 28432259 DOI: 10.1042/BCJ20161051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 03/24/2017] [Accepted: 04/21/2017] [Indexed: 11/17/2022]
Abstract
ATP-binding cassette (ABC) transporters are ubiquitously present in prokaryotic and eukaryotic cells. Binding of ATP to the nucleotide-binding domains (NBDs) elicits major conformational changes of the transporters resulting in the transport of the substrate across the membrane. The availability of a crystal structure of the NBDs enabled us to elucidate the local structure and small-scale dynamics in the NBDs. Here, we labeled the ABC transporter MsbA, a homodimeric flippase from Escherichia coli, with a fluorescent probe, Alexa532, within the NBDs. ATP application elicited collisional quenching, whereas no quenching was observed after the addition of ATP analogs or ATP hydrolysis inhibitors. The Alexa532-conjugated MsbA variants exhibited transition metal ion Förster resonance energy transfer (tmFRET) after the addition of Ni2+, and ATP decreased this Ni2+-mediated FRET of the NBDs. Structure modeling developed from crystallographic data and examination of tmFRET measurements of MsbA variants in the absence of ATP revealed the presence of metal ion-associated pockets (MiAPs) in the NBDs. Three histidines were predicted to participate in chelating Ni2+ in the two possible MiAPs. Performing histidine-substitution experiments with the NBDs showed that the dissociation constant for Ni2+ of MiAP2 was smaller than that of MiAP1. The structural allocation of the MiAPs was further supported by showing that the addition of Cu2+ resulted in higher quenching than Ni2+ Taken together, the present study showed that the NBDs contain two native binding sites for metal ions and ATP addition affects the Ni2+-binding activity of the MiAPs.
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16
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Abstract
Annexin A4 (Anx4) is a cytosolic calcium-binding protein with four repeat domains, each containing one calcium-binding site (CBS). The protein interacts with the phospholipid membrane through the CBS-coordinated calcium ion, although the role of each CBS in the calcium-dependent association is unclear. To determine the role of each CBS, 15 CBS-abolished variants were produced in various combinations by substitution of a calcium-liganding residue on each CBS by Ala. Various mutant combinations produced different influences on calcium-dependent membrane-binding behavior and on the sodium-dependent dissociation of membrane-bound Anx4. Our data suggest the interaction of Anx4 with the lipid membrane consists of strong and weak interactions. CBSs I and IV mediate formation of strong interactions, while CBSs II and III are important for weak interactions. We also suggest Anx4 binds the lipid membrane through CBSs I and IV in the cytoplasmic fluids.
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Affiliation(s)
- Yasuhiro Arii
- a Department of Food Science and Nutrition , School of Human Environmental Sciences, Mukogawa Women's University , Nishinomiya , Japan
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