1
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Bellanda M, Damulewicz M, Zambelli B, Costanzi E, Gregoris F, Mammi S, Tosatto SCE, Costa R, Minervini G, Mazzotta GM. A PDZ scaffolding/CaM-mediated pathway in Cryptochrome signaling. Protein Sci 2024; 33:e4914. [PMID: 38358255 PMCID: PMC10868427 DOI: 10.1002/pro.4914] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 12/12/2023] [Accepted: 01/13/2024] [Indexed: 02/16/2024]
Abstract
Cryptochromes are cardinal constituents of the circadian clock, which orchestrates daily physiological rhythms in living organisms. A growing body of evidence points to their participation in pathways that have not traditionally been associated with circadian clock regulation, implying that cryptochromes may be subject to modulation by multiple signaling mechanisms. In this study, we demonstrate that human CRY2 (hCRY2) forms a complex with the large, modular scaffolding protein known as Multi-PDZ Domain Protein 1 (MUPP1). This interaction is facilitated by the calcium-binding protein Calmodulin (CaM) in a calcium-dependent manner. Our findings suggest a novel cooperative mechanism for the regulation of mammalian cryptochromes, mediated by calcium ions (Ca2+ ) and CaM. We propose that this Ca2+ /CaM-mediated signaling pathway may be an evolutionarily conserved mechanism that has been maintained from Drosophila to mammals, most likely in relation to its potential role in the broader context of cryptochrome function and regulation. Further, the understanding of cryptochrome interactions with other proteins and signaling pathways could lead to a better definition of its role within the intricate network of molecular interactions that govern circadian rhythms.
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Affiliation(s)
| | - Milena Damulewicz
- Department of Cell Biology and ImagingJagiellonian UniversityKrakówPoland
| | - Barbara Zambelli
- Department of Pharmacy and BiotechnologyUniversity of BolognaBolognaItaly
| | - Elisa Costanzi
- Department of Chemical SciencesUniversity of PadovaPadovaItaly
| | | | - Stefano Mammi
- Department of Chemical SciencesUniversity of PadovaPadovaItaly
| | | | - Rodolfo Costa
- Department of BiologyUniversity of PadovaPadovaItaly
- Institute of Neuroscience, National Research Council of Italy (CNR)PadovaItaly
- Chronobiology Section, Faculty of Health and Medical SciencesUniversity of SurreyGuildfordUK
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2
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Pierro A, Tamburrini KC, Leguenno H, Gerbaud G, Etienne E, Guigliarelli B, Belle V, Zambelli B, Mileo E. In-cell investigation of the conformational landscape of the GTPase UreG by SDSL-EPR. iScience 2023; 26:107855. [PMID: 37766968 PMCID: PMC10520941 DOI: 10.1016/j.isci.2023.107855] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 07/07/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
UreG is a cytosolic GTPase involved in the maturation network of urease, an Ni-containing bacterial enzyme. Previous investigations in vitro showed that UreG features a flexible tertiary organization, making this protein the first enzyme discovered to be intrinsically disordered. To determine whether this heterogeneous behavior is maintained in the protein natural environment, UreG structural dynamics was investigated directly in intact bacteria by in-cell EPR. This approach, based on site-directed spin labeling coupled to electron paramagnetic resonance (SDSL-EPR) spectroscopy, enables the study of proteins in their native environment. The results show that UreG maintains heterogeneous structural landscape in-cell, existing in a conformational ensemble of two major conformers, showing either random coil-like or compact properties. These data support the physiological relevance of the intrinsically disordered nature of UreG and indicates a role of protein flexibility for this specific enzyme, possibly related to the regulation of promiscuous protein interactions for metal ion delivery.
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Affiliation(s)
- Annalisa Pierro
- Aix Marseille Univ, CNRS, BIP, IMM, 13009 Marseille, France
- Department of Chemistry, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Ketty Concetta Tamburrini
- Aix Marseille Univ, CNRS, AFMB, 13009 Marseille, France
- INRAE, Aix Marseille Univ, BBF, 13009 Marseille, France
| | - Hugo Leguenno
- Aix Marseille Univ, CNRS, IMM, Microscopy Core Facility, 13009 Marseille, France
| | | | | | | | - Valérie Belle
- Aix Marseille Univ, CNRS, BIP, IMM, 13009 Marseille, France
| | - Barbara Zambelli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, 40127 Bologna, Italy
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3
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Zambelli B. Intracellular phase separation and its role in nickel sensing. Trends Cell Biol 2023; 33:732-733. [PMID: 37433710 DOI: 10.1016/j.tcb.2023.06.008] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 06/22/2023] [Indexed: 07/13/2023]
Abstract
Nickel homeostasis in many bacteria is controlled by the nickel-sensor NikR. A recent study by Cao et al. found that Escherichia coli NikR undergoes phase separation and that this event enhances its function as a nickel-dependent transcriptional repressor. The results suggest that phase separation is functional for bacterial metal homeostasis.
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Affiliation(s)
- Barbara Zambelli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy.
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4
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Zambelli B, Basak P, Hu H, Piccioli M, Musiani F, Broll V, Imbert L, Boisbouvier J, Maroney MJ, Ciurli S. The structure of the high-affinity nickel-binding site in the Ni,Zn-HypA•UreE2 complex. Metallomics 2023; 15:mfad003. [PMID: 36638839 PMCID: PMC10001889 DOI: 10.1093/mtomcs/mfad003] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 01/11/2023] [Indexed: 01/15/2023]
Abstract
The maturation pathway for the nickel-dependent enzyme urease utilizes the protein UreE as a metallochaperone to supply Ni(II) ions. In Helicobacter pylori urease maturation also requires HypA and HypB, accessory proteins that are commonly associated with hydrogenase maturation. Herein we report on the characterization of a protein complex formed between HypA and the UreE2 dimer. Nuclear magnetic resonance (NMR) coupled with molecular modelling show that the protein complex apo, Zn-HypA•UreE2, forms between the rigorously conserved Met-His-Glu (MHE motif) Ni-binding N-terminal sequence of HypA and the two conserved His102A and His102B located at the dimer interface of UreE2. This complex forms in the absence of Ni(II) and is supported by extensive protein contacts that include the use of the C-terminal sequences of UreE2 to form additional strands of β-sheet with the Ni-binding domain of HypA. The Ni-binding properties of apo, Zn-HypA•UreE2 and the component proteins were investigated by isothermal titration calorimetry using a global fitting strategy that included all of the relevant equilibria, and show that the Ni,Zn-HypA•UreE2 complex contains a single Ni(II)-binding site with a sub-nanomolar KD. The structural features of this novel Ni(II) site were elucidated using proteins produced with specifically deuterated amino acids, protein point mutations, and the analyses of X-ray absorption spectroscopy, hyperfine shifted NMR features, as well as molecular modeling coupled with quantum-mechanical calculations. The results show that the complex contains a six-coordinate, high-spin Ni(II) site with ligands provided by both component proteins.
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Affiliation(s)
- Barbara Zambelli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Bologna,Italy
| | - Priyanka Basak
- Department of Chemistry and Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, USA
| | - Heidi Hu
- Department of Chemistry and Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, USA
| | - Mario Piccioli
- Centre for Magnetic Resonance, Department of Chemistry, University of Florence, Florence Italy
| | - Francesco Musiani
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Bologna,Italy
| | - Valquiria Broll
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Bologna,Italy
| | - Lionel Imbert
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), Grenoble, France
| | - Jerome Boisbouvier
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), Grenoble, France
| | - Michael J Maroney
- Department of Chemistry and Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, USA
| | - Stefano Ciurli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Bologna,Italy
- Centre for Magnetic Resonance, Department of Chemistry, University of Florence, Florence Italy
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Beniamino Y, Cenni V, Piccioli M, Ciurli S, Zambelli B. The Ni(II)-Binding Activity of the Intrinsically Disordered Region of Human NDRG1, a Protein Involved in Cancer Development. Biomolecules 2022; 12:biom12091272. [PMID: 36139110 PMCID: PMC9496542 DOI: 10.3390/biom12091272] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/31/2022] [Accepted: 09/05/2022] [Indexed: 11/16/2022] Open
Abstract
Nickel exposure is associated with tumors of the respiratory tract such as lung and nasal cancers, acting through still-uncharacterized mechanisms. Understanding the molecular basis of nickel-induced carcinogenesis requires unraveling the mode and the effects of Ni(II) binding to its intracellular targets. A possible Ni(II)-binding protein and a potential focus for cancer treatment is hNDRG1, a protein induced by Ni(II) through the hypoxia response pathway, whose expression correlates with higher cancer aggressiveness and resistance to chemotherapy in lung tissue. The protein sequence contains a unique C-terminal sequence of 83 residues (hNDRG1*C), featuring a three-times-repeated decapeptide, involved in metal binding, lipid interaction and post-translational phosphorylation. In the present work, the biochemical and biophysical characterization of unmodified hNDRG1*C was performed. Bioinformatic analysis assigned it to the family of the intrinsically disordered regions and the absence of secondary and tertiary structure was experimentally proven by circular dichroism and NMR. Isothermal titration calorimetry revealed the occurrence of a Ni(II)-binding event with micromolar affinity. Detailed information on the Ni(II)-binding site and on the residues involved was obtained in an extensive NMR study, revealing an octahedral paramagnetic metal coordination that does not cause any major change of the protein backbone, which is coherent with CD analysis. hNDRG1*C was found in a monomeric form by light-scattering experiments, while the full-length hNDRG1 monomer was found in equilibrium between the dimer and tetramer, both in solution and in human cell lines. The results are the first essential step for understanding the cellular function of hNDRG1*C at the molecular level, with potential future applications to clarify its role and the role of Ni(II) in cancer development.
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Affiliation(s)
- Ylenia Beniamino
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale Giuseppe Fanin 40, 40127 Bologna, Italy
| | - Vittoria Cenni
- CNR Institute of Molecular Genetics “Luigi-Luca Cavalli-Sforza” Unit of Bologna, Via di Barbiano 1/10, 40136 Bologna, Italy
| | - Mario Piccioli
- Department of Chemistry, Center for Magnetic Resonance, University of Florence, 50121 Florence, Italy
| | - Stefano Ciurli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale Giuseppe Fanin 40, 40127 Bologna, Italy
- Correspondence: (S.C.); (B.Z.); Tel.: +38-051-2096204 (S.C.); +38-051-2096233 (B.Z.)
| | - Barbara Zambelli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale Giuseppe Fanin 40, 40127 Bologna, Italy
- Correspondence: (S.C.); (B.Z.); Tel.: +38-051-2096204 (S.C.); +38-051-2096233 (B.Z.)
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6
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Basak P, Zambelli B, Cabelli DE, Ciurli S, Maroney MJ. Pro5 is not essential for the formation of ‘Ni-hook’ in nickel superoxide dismutase. J Inorg Biochem 2022; 234:111858. [DOI: 10.1016/j.jinorgbio.2022.111858] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 03/30/2022] [Accepted: 05/07/2022] [Indexed: 01/23/2023]
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7
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Mazzei L, Musiani F, Żerko S, Koźminski W, Cianci M, Beniamino Y, Ciurli S, Zambelli B. Structure, dynamics, and function of SrnR, a transcription factor for nickel-dependent gene expression. Metallomics 2021; 13:6445039. [PMID: 34850061 DOI: 10.1093/mtomcs/mfab069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [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: 07/20/2021] [Accepted: 11/18/2021] [Indexed: 11/14/2022]
Abstract
Streptomyces griseus, a bacterium producing antibacterial drugs and featuring possible application in phytoremediation, expresses two metal-dependent superoxide dismutase (SOD) enzymes, containing either Fe(II) or Ni(II) in their active site. In particular, the alternative expression of the two proteins occurs in a metal-dependent mode, with the Fe(II)-enzyme gene (sodF) repressed at high intracellular Ni(II) concentrations by a two-component system (TCS). This complex involves two proteins, namely SgSrnR and SgSrnQ, which represent the transcriptional regulator and the Ni(II) sensor of the system, respectively. SgSrnR belongs to the ArsR/SmtB family of metal-dependent transcription factors; in the apo-form and in the absence of SgSrnQ, it can bind the DNA operator of sodF, upregulating gene transcription. According to a recently proposed hypothesis, Ni(II) binding to SgSrnQ would promote its interaction with SgSrnR, causing the release of the complex from DNA and the consequent downregulation of the sodF expression. SgSrnQ is predicted to be highly disordered, thus the understanding, at the molecular level, of how the SgSrnR/SgSrnQ TCS specifically responds to Ni(II) requires the knowledge of the structural, dynamic, and functional features of SgSrnR. These were investigated synergistically in this work using X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, atomistic molecular dynamics calculations, isothermal titration calorimetry, and in silico molecular docking. The results reveal that the homodimeric apo-SgSrnR binds to its operator in a two-step process that involves the more rigid globular portion of the protein and leaves its largely disordered regions available to possibly interact with the disordered SgSrnQ in a Ni-dependent process.
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Affiliation(s)
- Luca Mazzei
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, Via Giuseppe Fanin 40, I-40127 Bologna. Italy
| | - Francesco Musiani
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, Via Giuseppe Fanin 40, I-40127 Bologna. Italy
| | - Szymon Żerko
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02-089, Warsaw, Poland
| | - Wiktor Koźminski
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02-089, Warsaw, Poland
| | - Michele Cianci
- Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche, Via Brecce Bianche, I-60131 Ancona, Italy
| | - Ylenia Beniamino
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, Via Giuseppe Fanin 40, I-40127 Bologna. Italy
| | - Stefano Ciurli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, Via Giuseppe Fanin 40, I-40127 Bologna. Italy
| | - Barbara Zambelli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, Via Giuseppe Fanin 40, I-40127 Bologna. Italy
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Darrouzet E, Rinaldi C, Zambelli B, Ciurli S, Cavazza C. Revisiting the CooJ family, a potential chaperone for nickel delivery to [NiFe]‑carbon monoxide dehydrogenase. J Inorg Biochem 2021; 225:111588. [PMID: 34530332 DOI: 10.1016/j.jinorgbio.2021.111588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 05/31/2021] [Revised: 08/17/2021] [Accepted: 08/18/2021] [Indexed: 11/21/2022]
Abstract
Nickel insertion into nickel-dependent carbon monoxide dehydrogenase (CODH) represents a key step in the enzyme activation. This is the last step of the biosynthesis of the active site, which contains an atypical heteronuclear NiFe4S4 cluster known as the C-cluster. The enzyme maturation is performed by three accessory proteins, namely CooC, CooT and CooJ. Among them, CooJ from Rhodospirillum rubrum is a histidine-rich protein containing two distinct and spatially separated Ni(II)-binding sites: a N-terminal high affinity site (HAS) and a histidine tail at the C-terminus. In 46 CooJ homologues, the HAS motif was found to be strictly conserved with a H(W/F)XXHXXXH sequence. Here, a proteome database search identified at least 150 CooJ homologues and revealed distinct motifs for HAS, featuring 2, 3 or 4 histidines. The purification and biophysical characterization of three representative members of this protein family showed that they are all homodimers able to bind Ni(II) ions via one or two independent binding sites. Initially thought to be present only in R. rubrum, this study strongly suggests that CooJ could play a significant role in CODH maturation or in nickel homeostasis.
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Affiliation(s)
- Elisabeth Darrouzet
- University of Grenoble Alpes, CEA, CNRS, IRIG, CBM, F-38000 Grenoble, France
| | - Clara Rinaldi
- University of Grenoble Alpes, CEA, CNRS, IRIG, CBM, F-38000 Grenoble, France
| | - Barbara Zambelli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Via Giuseppe Fanin 40, I-40127 Bologna, Italy
| | - Stefano Ciurli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Via Giuseppe Fanin 40, I-40127 Bologna, Italy
| | - Christine Cavazza
- University of Grenoble Alpes, CEA, CNRS, IRIG, CBM, F-38000 Grenoble, France.
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9
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Manoli F, Doria F, Colombo G, Zambelli B, Freccero M, Manet I. The Binding Pocket at the Interface of Multimeric Telomere G-quadruplexes: Myth or Reality? Chemistry 2021; 27:11707-11720. [PMID: 34152657 PMCID: PMC8456957 DOI: 10.1002/chem.202101486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 04/26/2021] [Indexed: 01/23/2023]
Abstract
Human telomeric DNA with hundreds of repeats of the 5'-TTAGGG-3' motif plays a crucial role in several biological processes. It folds into G-quadruplex (G4) structures and features a pocket at the interface of two contiguous G4 blocks. Up to now no structural NMR and crystallographic data are available for ligands interacting with contiguous G4s. Naphthalene diimide monomers and dyads were investigated as ligands of a dimeric G4 of human telomeric DNA comparing the results with those of the model monomeric G4. Time-resolved fluorescence, circular dichroism, isothermal titration calorimetry and molecular modeling were used to elucidate binding features. Ligand fluorescence lifetime and induced circular dichroism unveiled occupancy of the binding site at the interface. Thermodynamic parameters confirmed the hypothesis as they remarkably change for the dyad complexes of the monomeric and dimeric telomeric G4. The bi-functional ligand structure of the dyads is a fundamental requisite for binding at the G4 interface as only the dyads engage in complexes with 1 : 1 stoichiometry, lodging in the pocket at the interface and establishing multiple interactions with the DNA skeleton. In the absence of NMR and crystallographic data, our study affords important proofs of binding at the interface pocket and clues on the role played by the ligand structure.
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Affiliation(s)
- Francesco Manoli
- Institute for Organic Synthesis and Photoreactivity (ISOF)National Research Council (CNR)Via P. Gobetti 10140129BolognaItaly
| | - Filippo Doria
- Department of ChemistryUniversity of PaviaV. le Taramelli 1027100PaviaItaly
| | - Giorgio Colombo
- Department of ChemistryUniversity of PaviaV. le Taramelli 1027100PaviaItaly
| | - Barbara Zambelli
- Department of Pharmacy and BiotechnologyUniversity of BolognaV. le Fanin 4040127BolognaItaly
| | - Mauro Freccero
- Department of ChemistryUniversity of PaviaV. le Taramelli 1027100PaviaItaly
| | - Ilse Manet
- Institute for Organic Synthesis and Photoreactivity (ISOF)National Research Council (CNR)Via P. Gobetti 10140129BolognaItaly
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Costanzi E, Coletti A, Zambelli B, Macchiarulo A, Bellanda M, Battistutta R. Calmodulin binds to the STAS domain of SLC26A5 prestin with a calcium-dependent, one-lobe, binding mode. J Struct Biol 2021; 213:107714. [PMID: 33667636 DOI: 10.1016/j.jsb.2021.107714] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 01/14/2021] [Accepted: 02/25/2021] [Indexed: 10/22/2022]
Abstract
SLC26A5 transporter prestin is fundamental for the higher hearing sensitivity and frequency selectivity of mammals. Prestin is a voltage-dependent transporter found in the cochlear outer hair cells responsible for their electromotility. Intracellular chloride binding is considered essential for voltage sensitivity and electromotility. Prestin is composed by a transmembrane domain and by a cytosolic domain called STAS. There is evidence of a calcium/calmodulin regulation of prestin mediated by the STAS domain. Using different biophysical techniques, namely SEC, CD, ITC, MST, NMR and SAXS, here we demonstrate and characterize the direct interaction between calmodulin and prestin STAS. We show that the interaction is calcium-dependent and that involves residues at the N-terminal end of the "variable loop". This is an intrinsically disordered insertion typical of the STAS domains of the SLC26 family of transporters whose function is still unclear. We derive a low-resolution model of the STAS/CaM complex, where only one lobe of calmodulin is engaged in the interaction, and build a model for the entire dimeric prestin in complex with CaM, which can use the unoccupied lobe to interact with other regions of prestin or with other regulatory proteins. We show that also a non-mammalian STAS can interact with calmodulin via the variable loop. These data start to shed light on the regulatory role of the STAS variable loop of prestin.
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Affiliation(s)
- Elisa Costanzi
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131 Padova, Italy
| | - Alice Coletti
- Department of Pharmaceutical Sciences, University of Perugia, via del Liceo 1, 06123 Perugia, Italy; Department of Pharmacy, University of Chieti-Pescara, via dei Vestini 31, 66100 Chieti, Italy
| | - Barbara Zambelli
- Department of Pharmacy and Biotechnology, University of Bologna, viale Fanin 40, 40127 Bologna, Italy
| | - Antonio Macchiarulo
- Department of Pharmaceutical Sciences, University of Perugia, via del Liceo 1, 06123 Perugia, Italy
| | - Massimo Bellanda
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131 Padova, Italy.
| | - Roberto Battistutta
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131 Padova, Italy.
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11
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Pierro A, Etienne E, Gerbaud G, Guigliarelli B, Ciurli S, Belle V, Zambelli B, Mileo E. Nickel and GTP Modulate Helicobacter pylori UreG Structural Flexibility. Biomolecules 2020; 10:E1062. [PMID: 32708696 PMCID: PMC7408563 DOI: 10.3390/biom10071062] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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: 06/02/2020] [Revised: 06/25/2020] [Accepted: 07/10/2020] [Indexed: 12/14/2022] Open
Abstract
UreG is a P-loop GTP hydrolase involved in the maturation of nickel-containing urease, an essential enzyme found in plants, fungi, bacteria, and archaea. This protein couples the hydrolysis of GTP to the delivery of Ni(II) into the active site of apo-urease, interacting with other urease chaperones in a multi-protein complex necessary for enzyme activation. Whereas the conformation of Helicobacter pylori (Hp) UreG was solved by crystallography when it is in complex with two other chaperones, in solution the protein was found in a disordered and flexible form, defining it as an intrinsically disordered enzyme and indicating that the well-folded structure found in the crystal state does not fully reflect the behavior of the protein in solution. Here, isothermal titration calorimetry and site-directed spin labeling coupled to electron paramagnetic spectroscopy were successfully combined to investigate HpUreG structural dynamics in solution and the effect of Ni(II) and GTP on protein mobility. The results demonstrate that, although the protein maintains a flexible behavior in the metal and nucleotide bound forms, concomitant addition of Ni(II) and GTP exerts a structural change through the crosstalk of different protein regions.
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Affiliation(s)
- Annalisa Pierro
- Aix Marseille Univ, CNRS, BIP, Bioénergétique et Ingénierie des Protéines, IMM, Marseille, France; (A.P.); (E.E.); (G.G.); (B.G.); (V.B.)
| | - Emilien Etienne
- Aix Marseille Univ, CNRS, BIP, Bioénergétique et Ingénierie des Protéines, IMM, Marseille, France; (A.P.); (E.E.); (G.G.); (B.G.); (V.B.)
| | - Guillaume Gerbaud
- Aix Marseille Univ, CNRS, BIP, Bioénergétique et Ingénierie des Protéines, IMM, Marseille, France; (A.P.); (E.E.); (G.G.); (B.G.); (V.B.)
| | - Bruno Guigliarelli
- Aix Marseille Univ, CNRS, BIP, Bioénergétique et Ingénierie des Protéines, IMM, Marseille, France; (A.P.); (E.E.); (G.G.); (B.G.); (V.B.)
| | - Stefano Ciurli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, 40127 Bologna, Italy;
| | - Valérie Belle
- Aix Marseille Univ, CNRS, BIP, Bioénergétique et Ingénierie des Protéines, IMM, Marseille, France; (A.P.); (E.E.); (G.G.); (B.G.); (V.B.)
| | - Barbara Zambelli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, 40127 Bologna, Italy;
| | - Elisabetta Mileo
- Aix Marseille Univ, CNRS, BIP, Bioénergétique et Ingénierie des Protéines, IMM, Marseille, France; (A.P.); (E.E.); (G.G.); (B.G.); (V.B.)
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12
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Ngnameko CR, Marchetti L, Zambelli B, Quotadamo A, Roncarati D, Bertelli D, Njayou FN, Smith SI, Moundipa PF, Costi MP, Pellati F. New Insights into Bioactive Compounds from the Medicinal Plant Spathodea campanulata P. Beauv. and Their Activity against Helicobacter pylori. Antibiotics (Basel) 2020; 9:antibiotics9050258. [PMID: 32429263 PMCID: PMC7277392 DOI: 10.3390/antibiotics9050258] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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: 03/21/2020] [Revised: 05/12/2020] [Accepted: 05/13/2020] [Indexed: 12/24/2022] Open
Abstract
The medicinal plant Spathodea campanulata P. Beauv. (Bignoniaceae) has been traditionally applied for the prevention and treatment of diseases of the kidney and urinary system, the skin, the gastrointestinal tract, and inflammation in general. The present work shows for the first time how chemical components from this plant inhibit Helicobacter pylori growth by urease inhibition and modulation of virulence factors. The crude extract and the main fractions of S. campanulata bark were tested on H. pylori isolated strains and the active ones were further fractionated. Fractions and sub-fractions of the plant crude extract were characterized by ultra-high-performance liquid chromatographic tandem high resolution-mass spectrometry detection (UHPLC-HRMS). Several phenolics and triterpenoids were identified. Among the sub-fractions obtained, SB2 showed the capacity to inhibit H. pylori urease in a heterologous bacterial model. One additional sub-fraction (SE3) was able to simultaneously modulate the expression of two adhesins (HopZ and BabA) and one cytotoxin (CagA). The flavonol kaempferol was identified as the most interesting compound that deserves further investigation as a new hit for its capacity to modulate H. pylori virulence factors.
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Affiliation(s)
- Corinne Raïssa Ngnameko
- Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 103, 41125 Modena, Italy; (C.R.N.); (L.M.); (A.Q.); (D.B.); (M.P.C.)
- Department of Biochemistry, Faculty of Science, The University of Yaounde I, P. Box 812 Yaounde, Cameroon;
| | - Lucia Marchetti
- Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 103, 41125 Modena, Italy; (C.R.N.); (L.M.); (A.Q.); (D.B.); (M.P.C.)
- Doctorate School in Clinical and Experimental Medicine (CEM), University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Barbara Zambelli
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum University of Bologna, Viale Fanin 44, 40127 Bologna, Italy; (B.Z.); (D.R.)
| | - Antonio Quotadamo
- Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 103, 41125 Modena, Italy; (C.R.N.); (L.M.); (A.Q.); (D.B.); (M.P.C.)
- Doctorate School in Clinical and Experimental Medicine (CEM), University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Davide Roncarati
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum University of Bologna, Viale Fanin 44, 40127 Bologna, Italy; (B.Z.); (D.R.)
| | - Davide Bertelli
- Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 103, 41125 Modena, Italy; (C.R.N.); (L.M.); (A.Q.); (D.B.); (M.P.C.)
| | - Frederic Nico Njayou
- Department of Biochemistry, Faculty of Science, The University of Yaounde I, P. Box 812 Yaounde, Cameroon;
| | - Stella I. Smith
- Nigerian Institute of Medical Research, PMB 2013, Yaba, Lagos 100001, Nigeria;
| | - Paul F. Moundipa
- Department of Biochemistry, Faculty of Science, The University of Yaounde I, P. Box 812 Yaounde, Cameroon;
- Correspondence: (P.F.M.); (F.P.); Tel.: +237-222-314-527 (P.F.M.); +39-059-2058565 (F.P.)
| | - Maria Paola Costi
- Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 103, 41125 Modena, Italy; (C.R.N.); (L.M.); (A.Q.); (D.B.); (M.P.C.)
| | - Federica Pellati
- Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 103, 41125 Modena, Italy; (C.R.N.); (L.M.); (A.Q.); (D.B.); (M.P.C.)
- Correspondence: (P.F.M.); (F.P.); Tel.: +237-222-314-527 (P.F.M.); +39-059-2058565 (F.P.)
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13
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Zambelli B, Mazzei L, Ciurli S. Intrinsic disorder in the nickel-dependent urease network. Dancing Protein Clouds: Intrinsically Disordered Proteins in Health and Disease, Part B 2020; 174:307-330. [DOI: 10.1016/bs.pmbts.2020.05.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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14
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Alfano M, Veronesi G, Musiani F, Zambelli B, Signor L, Proux O, Rovezzi M, Ciurli S, Cavazza C. A Solvent‐Exposed Cysteine Forms a Peculiar Ni
II
‐Binding Site in the Metallochaperone CooT from
Rhodospirillum rubrum. Chemistry 2019; 25:15351-15360. [DOI: 10.1002/chem.201903492] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Indexed: 11/11/2022]
Affiliation(s)
- Marila Alfano
- IRIG, CBMUniversity of Grenoble Alpes, CEA, CNRS 38000 Grenoble France
| | - Giulia Veronesi
- IRIG, CBMUniversity of Grenoble Alpes, CEA, CNRS 38000 Grenoble France
| | - Francesco Musiani
- Laboratory of Bioinorganic ChemistryDepartment of Pharmacy and BiotechnologyUniversity of Bologna Via Giuseppe Fanin 40 40127 Bologna Italy
| | - Barbara Zambelli
- Laboratory of Bioinorganic ChemistryDepartment of Pharmacy and BiotechnologyUniversity of Bologna Via Giuseppe Fanin 40 40127 Bologna Italy
| | - Luca Signor
- IRIG, IBSUniversity of Grenoble Alpes, CEA, CNRS 38000 Grenoble France
| | - Olivier Proux
- OSUG, FAMEUniversity of Grenoble Alpes, CNRS, IRDIrstea, Météo France 38000 Grenoble France
| | - Mauro Rovezzi
- OSUG, FAMEUniversity of Grenoble Alpes, CNRS, IRDIrstea, Météo France 38000 Grenoble France
| | - Stefano Ciurli
- Laboratory of Bioinorganic ChemistryDepartment of Pharmacy and BiotechnologyUniversity of Bologna Via Giuseppe Fanin 40 40127 Bologna Italy
| | - Christine Cavazza
- IRIG, CBMUniversity of Grenoble Alpes, CEA, CNRS 38000 Grenoble France
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15
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Kappaun K, Martinelli AHS, Broll V, Zambelli B, Lopes FC, Ligabue-Braun R, Fruttero LL, Moyetta NR, Bonan CD, Carlini CR, Ciurli S. Soyuretox, an Intrinsically Disordered Polypeptide Derived from Soybean (Glycine Max) Ubiquitous Urease with Potential Use as a Biopesticide. Int J Mol Sci 2019; 20:E5401. [PMID: 31671552 PMCID: PMC6862595 DOI: 10.3390/ijms20215401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [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: 09/27/2019] [Revised: 10/27/2019] [Accepted: 10/28/2019] [Indexed: 02/07/2023] Open
Abstract
Ureases from different biological sources display non-ureolytic properties that contribute to plant defense, in addition to their classical enzymatic urea hydrolysis. Antifungal and entomotoxic effects were demonstrated for Jaburetox, an intrinsically disordered polypeptide derived from jack bean (Canavalia ensiformis) urease. Here we describe the properties of Soyuretox, a polypeptide derived from soybean (Glycine max) ubiquitous urease. Soyuretox was fungitoxic to Candida albicans, leading to the production of reactive oxygen species. Soyuretox further induced aggregation of Rhodnius prolixus hemocytes, indicating an interference on the insect immune response. No relevant toxicity of Soyuretox to zebrafish larvae was observed. These data suggest the presence of antifungal and entomotoxic portions of the amino acid sequences encompassing both Soyuretox and Jaburetox, despite their small sequence identity. Nuclear Magnetic Resonance (NMR) and circular dichroism (CD) spectroscopic data revealed that Soyuretox, in analogy with Jaburetox, possesses an intrinsic and largely disordered nature. Some folding is observed upon interaction of Soyuretox with sodium dodecyl sulfate (SDS) micelles, taken here as models for membranes. This observation suggests the possibility for this protein to modify its secondary structure upon interaction with the cells of the affected organisms, leading to alterations of membrane integrity. Altogether, Soyuretox can be considered a promising biopesticide for use in plant protection.
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Affiliation(s)
- Karine Kappaun
- Graduate Program in Medicine and Health Sciences, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre 90610-000, RS, Brazil.
| | - Anne H S Martinelli
- Department of Biophysics and Center of Biotechnology, Universidade Federal do Rio Grande do Sul, UFRGS, Porto Alegre 91501-970, RS, Brazil.
| | - Valquiria Broll
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, UFRGS, Porto Alegre 91501-970, RS, Brazil.
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, 40127 Bologna, Italy.
| | - Barbara Zambelli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, 40127 Bologna, Italy.
| | - Fernanda C Lopes
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, UFRGS, Porto Alegre 91501-970, RS, Brazil.
| | - Rodrigo Ligabue-Braun
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, UFRGS, Porto Alegre 91501-970, RS, Brazil.
| | - Leonardo L Fruttero
- Graduate Program in Medicine and Health Sciences, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre 90610-000, RS, Brazil.
- Department of Clinical Biochemistry, CIBICI-CONICET, Facultad de Ciencias Quimicas, Universidad Nacional de Córdoba, Córdoba 5000, Argentina.
| | - Natalia R Moyetta
- Department of Clinical Biochemistry, CIBICI-CONICET, Facultad de Ciencias Quimicas, Universidad Nacional de Córdoba, Córdoba 5000, Argentina.
| | - Carla D Bonan
- Department of Cellular and Molecular Biology, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre 91501-970, RS, Brazil.
| | - Celia R Carlini
- Graduate Program in Medicine and Health Sciences, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre 90610-000, RS, Brazil.
- Brain Institute-InsCer, Laboratory of Neurotoxins, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre 90610-000, RS, Brazil.
| | - Stefano Ciurli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, 40127 Bologna, Italy.
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16
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Abstract
Life is governed by a complex and tightly regulated sequence of biochemical reactions, catalyzed by enzymes. Characterizing enzyme activity is extremely important both to understand biological processes and to develop new industrial applications. Calorimetry represents an ideal system to measure kinetics of biochemical transformations, because it uses heat, always produced or absorbed during chemical reactions, as a probe.The following protocol describes the details of experimental setup and data analysis of isothermal titration calorimetry (ITC) experiments aimed to quantify the thermodynamic (ΔH) and kinetic (KM and kcat) parameters of enzyme catalysis. A general guideline to choose the right procedure according to the system under analysis is given, together with some instructions on how to adjust the experimental conditions for obtaining reliable data. The method to analyze the obtained raw ITC curves and to derive the kinetic parameters is described.
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Affiliation(s)
- Barbara Zambelli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy.
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17
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Gallego-Jara J, Terol GL, Écija Conesa A, Zambelli B, Cánovas Díaz M, de Diego Puente T. Characterization of acetyl-CoA synthetase kinetics and ATP-binding. Biochim Biophys Acta Gen Subj 2019; 1863:1040-1049. [PMID: 30928490 DOI: 10.1016/j.bbagen.2019.03.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/20/2019] [Accepted: 03/25/2019] [Indexed: 12/11/2022]
Abstract
BACKGROUND The superfamily of adenylating enzymes is a large family of enzymes broadly distributed from bacteria to humans. Acetyl-CoA synthetase (Acs), member of this family, is a metabolic enzyme with an essential role in Escherichia coli (E. coli) acetate metabolism, whose catalytic activity is regulated by acetylation/deacetylation in vivo. METHODS In this study, the kinetics and thermodynamic parameters of deacetylated and acetylated E. coli Acs were studied for the adenylating step. Moreover, the role of the T264, K270, D500 and K609 residues in catalysis and ATP-binding was also determined by Isothermal titration calorimetry. RESULTS The results showed that native Acs enzyme binds ATP in an endothermic way. The dissociation constant has been determined and ATP-binding showed no significant differences between acetylated and deacetylated enzyme, although kcat was much higher for the deacetylated enzyme. However, K609 lysine mutation resulted in an increase in ATP-Acs-affinity and in a total loss of enzymatic activity, while T264 and D500 mutant proteins showed a total loss of ATP-binding ability and a decrease in catalytic activity. K609 site-specified acetylation induced a change in Acs conformation which resulted in an exothermic and more energetic ATP-binding. CONCLUSIONS The differences in ATP-binding could explain the broadly conserved inactivation of Acs when K609 is acetylated. GENERAL SIGNIFICANCE The results presented in this study demonstrate the importance of the selected residues in Acs ATP-binding and represent an advance in our understanding of the adenylation step of the superfamily of adenylating enzymes and of their acetylation/deacetylation regulation.
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Affiliation(s)
- Julia Gallego-Jara
- Department of Biochemistry and Molecular Biology and Immunology (B), Faculty of Chemistry, University of Murcia, Campus of Espinardo, Regional Campus of International Excellence "Campus Mare Nostrum", P.O. Box 4021, Murcia E-30100, Spain.
| | - Gema Lozano Terol
- Department of Biochemistry and Molecular Biology and Immunology (B), Faculty of Chemistry, University of Murcia, Campus of Espinardo, Regional Campus of International Excellence "Campus Mare Nostrum", P.O. Box 4021, Murcia E-30100, Spain.
| | - Ana Écija Conesa
- Department of Biochemistry and Molecular Biology and Immunology (B), Faculty of Chemistry, University of Murcia, Campus of Espinardo, Regional Campus of International Excellence "Campus Mare Nostrum", P.O. Box 4021, Murcia E-30100, Spain
| | - Barbara Zambelli
- Laboratory of Bioinorganic Chemistry, University of Bologna, Department of Pharmacy and Biotechnology, Via Giuseppe Fanin 40, I-40127 Bologna, Italy
| | - Manuel Cánovas Díaz
- Department of Biochemistry and Molecular Biology and Immunology (B), Faculty of Chemistry, University of Murcia, Campus of Espinardo, Regional Campus of International Excellence "Campus Mare Nostrum", P.O. Box 4021, Murcia E-30100, Spain
| | - Teresa de Diego Puente
- Department of Biochemistry and Molecular Biology and Immunology (B), Faculty of Chemistry, University of Murcia, Campus of Espinardo, Regional Campus of International Excellence "Campus Mare Nostrum", P.O. Box 4021, Murcia E-30100, Spain
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18
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Alfano M, Pérard J, Carpentier P, Basset C, Zambelli B, Timm J, Crouzy S, Ciurli S, Cavazza C. The carbon monoxide dehydrogenase accessory protein CooJ is a histidine-rich multidomain dimer containing an unexpected Ni(II)-binding site. J Biol Chem 2019; 294:7601-7614. [PMID: 30858174 DOI: 10.1074/jbc.ra119.008011] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [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: 02/14/2019] [Revised: 03/09/2019] [Indexed: 01/14/2023] Open
Abstract
Activation of nickel enzymes requires specific accessory proteins organized in multiprotein complexes controlling metal transfer to the active site. Histidine-rich clusters are generally present in at least one of the metallochaperones involved in nickel delivery. The maturation of carbon monoxide dehydrogenase in the proteobacterium Rhodospirillum rubrum requires three accessory proteins, CooC, CooT, and CooJ, dedicated to nickel insertion into the active site, a distorted [NiFe3S4] cluster coordinated to an iron site. Previously, CooJ from R. rubrum (RrCooJ) has been described as a nickel chaperone with 16 histidines and 2 cysteines at its C terminus. Here, the X-ray structure of a truncated version of RrCooJ, combined with small-angle X-ray scattering data and a modeling study of the full-length protein, revealed a homodimer comprising a coiled coil with two independent and highly flexible His tails. Using isothermal calorimetry, we characterized several metal-binding sites (four per dimer) involving the His-rich motifs and having similar metal affinity (KD = 1.6 μm). Remarkably, biophysical approaches, site-directed mutagenesis, and X-ray crystallography uncovered an additional nickel-binding site at the dimer interface, which binds Ni(II) with an affinity of 380 nm Although RrCooJ was initially thought to be a unique protein, a proteome database search identified at least 46 bacterial CooJ homologs. These homologs all possess two spatially separated nickel-binding motifs: a variable C-terminal histidine tail and a strictly conserved H(W/F)X 2HX 3H motif, identified in this study, suggesting a dual function for CooJ both as a nickel chaperone and as a nickel storage protein.
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Affiliation(s)
- Marila Alfano
- From the Laboratory of Chemistry and Biology of Metals, Université Grenoble Alpes, CEA, CNRS, F-38000 Grenoble, France and
| | - Julien Pérard
- From the Laboratory of Chemistry and Biology of Metals, Université Grenoble Alpes, CEA, CNRS, F-38000 Grenoble, France and
| | - Philippe Carpentier
- From the Laboratory of Chemistry and Biology of Metals, Université Grenoble Alpes, CEA, CNRS, F-38000 Grenoble, France and
| | - Christian Basset
- From the Laboratory of Chemistry and Biology of Metals, Université Grenoble Alpes, CEA, CNRS, F-38000 Grenoble, France and
| | - Barbara Zambelli
- the Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, I-40127 Bologna, Italy
| | - Jennifer Timm
- From the Laboratory of Chemistry and Biology of Metals, Université Grenoble Alpes, CEA, CNRS, F-38000 Grenoble, France and
| | - Serge Crouzy
- From the Laboratory of Chemistry and Biology of Metals, Université Grenoble Alpes, CEA, CNRS, F-38000 Grenoble, France and
| | - Stefano Ciurli
- the Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, I-40127 Bologna, Italy
| | - Christine Cavazza
- From the Laboratory of Chemistry and Biology of Metals, Université Grenoble Alpes, CEA, CNRS, F-38000 Grenoble, France and
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19
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Spronk CAEM, Żerko S, Górka M, Koźmiński W, Bardiaux B, Zambelli B, Musiani F, Piccioli M, Basak P, Blum FC, Johnson RC, Hu H, Merrell DS, Maroney M, Ciurli S. Structure and dynamics of Helicobacter pylori nickel-chaperone HypA: an integrated approach using NMR spectroscopy, functional assays and computational tools. J Biol Inorg Chem 2018; 23:1309-1330. [PMID: 30264175 DOI: 10.1007/s00775-018-1616-y] [Citation(s) in RCA: 9] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 09/05/2018] [Indexed: 01/03/2023]
Abstract
Helicobacter pylori HypA (HpHypA) is a metallochaperone necessary for maturation of [Ni,Fe]-hydrogenase and urease, the enzymes required for colonization and survival of H. pylori in the gastric mucosa. HpHypA contains a structural Zn(II) site and a unique Ni(II) binding site at the N-terminus. X-ray absorption spectra suggested that the Zn(II) coordination depends on pH and on the presence of Ni(II). This study was performed to investigate the structural properties of HpHypA as a function of pH and Ni(II) binding, using NMR spectroscopy combined with DFT and molecular dynamics calculations. The solution structure of apo,Zn-HpHypA, containing Zn(II) but devoid of Ni(II), was determined using 2D, 3D and 4D NMR spectroscopy. The structure suggests that a Ni-binding and a Zn-binding domain, joined through a short linker, could undergo mutual reorientation. This flexibility has no physiological effect on acid viability or urease maturation in H. pylori. Atomistic molecular dynamics simulations suggest that Ni(II) binding is important for the conformational stability of the N-terminal helix. NMR chemical shift perturbation analysis indicates that no structural changes occur in the Zn-binding domain upon addition of Ni(II) in the pH 6.3-7.2 range. The structure of the Ni(II) binding site was probed using 1H NMR spectroscopy experiments tailored to reveal hyperfine-shifted signals around the paramagnetic metal ion. On this basis, two possible models were derived using quantum-mechanical DFT calculations. The results provide a comprehensive picture of the Ni(II) mode to HpHypA, important to rationalize, at the molecular level, the functional interactions of this chaperone with its protein partners.
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Affiliation(s)
- Chris A E M Spronk
- JSC Spronk, Vilnius, Lithuania.,Department of Molecular and Cell Biology, Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester, UK
| | - Szymon Żerko
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02-089, Warsaw, Poland
| | - Michał Górka
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02-089, Warsaw, Poland.,Faculty of Physics, Division of Biophysics, Institute of Experimental Physics, University of Warsaw, Pasteura 5, 02-093, Warsaw, Poland
| | - Wiktor Koźmiński
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02-089, Warsaw, Poland
| | - Benjamin Bardiaux
- Structural Bioinformatics Unit, Department of Structural Biology and Chemistry, Institut Pasteur, CNRS UMR3528, Paris, France
| | - Barbara Zambelli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, 40127, Bologna, Italy
| | - Francesco Musiani
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, 40127, Bologna, Italy
| | - Mario Piccioli
- Center for Magnetic Resonance, Department of Chemistry, University of Florence, Florence, Italy
| | - Priyanka Basak
- Department of Chemistry, University of Massachusetts, Amherst, MA, 01003, USA
| | - Faith C Blum
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
| | - Ryan C Johnson
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
| | - Heidi Hu
- Department of Chemistry, University of Massachusetts, Amherst, MA, 01003, USA
| | - D Scott Merrell
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
| | - Michael Maroney
- Department of Chemistry, University of Massachusetts, Amherst, MA, 01003, USA.
| | - Stefano Ciurli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, 40127, Bologna, Italy. .,Center for Magnetic Resonance, Department of Chemistry, University of Florence, Florence, Italy.
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20
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Sturlese M, Manta B, Bertarello A, Bonilla M, Lelli M, Zambelli B, Grunberg K, Mammi S, Comini MA, Bellanda M. The lineage-specific, intrinsically disordered N-terminal extension of monothiol glutaredoxin 1 from trypanosomes contains a regulatory region. Sci Rep 2018; 8:13716. [PMID: 30209332 PMCID: PMC6135854 DOI: 10.1038/s41598-018-31817-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 08/23/2018] [Indexed: 12/31/2022] Open
Abstract
Glutaredoxins (Grx) are small proteins conserved throughout all the kingdoms of life that are engaged in a wide variety of biological processes and share a common thioredoxin-fold. Among them, class II Grx are redox-inactive proteins involved in iron-sulfur (FeS) metabolism. They contain a single thiol group in their active site and use low molecular mass thiols such as glutathione as ligand for binding FeS-clusters. In this study, we investigated molecular aspects of 1CGrx1 from the pathogenic parasite Trypanosoma brucei brucei, a mitochondrial class II Grx that fulfills an indispensable role in vivo. Mitochondrial 1CGrx1 from trypanosomes differs from orthologues in several features including the presence of a parasite-specific N-terminal extension (NTE) whose role has yet to be elucidated. Previously we have solved the structure of a truncated form of 1CGrx1 containing only the conserved glutaredoxin domain but lacking the NTE. Our aim here is to investigate the effect of the NTE on the conformation of the protein. We therefore solved the NMR structure of the full-length protein, which reveals subtle but significant differences with the structure of the NTE-less form. By means of different experimental approaches, the NTE proved to be intrinsically disordered and not involved in the non-redox dependent protein dimerization, as previously suggested. Interestingly, the portion comprising residues 65–76 of the NTE modulates the conformational dynamics of the glutathione-binding pocket, which may play a role in iron-sulfur cluster assembly and delivery. Furthermore, we disclosed that the class II-strictly conserved loop that precedes the active site is critical for stabilizing the protein structure. So far, this represents the first communication of a Grx containing an intrinsically disordered region that defines a new protein subgroup within class II Grx.
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Affiliation(s)
- Mattia Sturlese
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131, Padova, Italy.,Molecular Modeling Section (MMS), Department of Pharmaceutical and Pharmacological Sciences, University of Padova, via Marzolo 5, Padova, Italy
| | - Bruno Manta
- Institut Pasteur de Montevideo, Mataojo 2020, 11400, Montevideo, Uruguay.,Laboratorio de Fisicoquímica Biológica, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Igua 4425, 11400, Montevideo, Uruguay.,New England Biolabs, 240 County Road, Ipswich, MA, 01938, USA
| | - Andrea Bertarello
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131, Padova, Italy
| | - Mariana Bonilla
- Institut Pasteur de Montevideo, Mataojo 2020, 11400, Montevideo, Uruguay
| | - Moreno Lelli
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino (FI), Italy.,Magnetic Resonance Center (CERM), University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino (FI), Italy.,Centre de RMN à Très Hauts Champs, Institut des Sciences Analytiques (UMR 5280 - CNRS, ENS Lyon, UCB Lyon 1), Université de Lyon, 5 rue de la Doua, 69100, Villeurbanne, France
| | - Barbara Zambelli
- Department of Pharmacy and Biotechnology, University of Bologna, Viale Giuseppe Fanin 40, 40127, Bologna, Italy
| | - Karin Grunberg
- Institut Pasteur de Montevideo, Mataojo 2020, 11400, Montevideo, Uruguay
| | - Stefano Mammi
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131, Padova, Italy
| | - Marcelo A Comini
- Institut Pasteur de Montevideo, Mataojo 2020, 11400, Montevideo, Uruguay
| | - Massimo Bellanda
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131, Padova, Italy.
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21
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Mazzotta GM, Bellanda M, Minervini G, Damulewicz M, Cusumano P, Aufiero S, Stefani M, Zambelli B, Mammi S, Costa R, Tosatto SCE. Calmodulin Enhances Cryptochrome Binding to INAD in Drosophila Photoreceptors. Front Mol Neurosci 2018; 11:280. [PMID: 30177872 PMCID: PMC6109769 DOI: 10.3389/fnmol.2018.00280] [Citation(s) in RCA: 6] [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: 11/14/2017] [Accepted: 07/24/2018] [Indexed: 12/13/2022] Open
Abstract
Light is the main environmental stimulus that synchronizes the endogenous timekeeping systems in most terrestrial organisms. Drosophila cryptochrome (dCRY) is a light-responsive flavoprotein that detects changes in light intensity and wavelength around dawn and dusk. We have previously shown that dCRY acts through Inactivation No Afterpotential D (INAD) in a light-dependent manner on the Signalplex, a multiprotein complex that includes visual-signaling molecules, suggesting a role for dCRY in fly vision. Here, we predict and demonstrate a novel Ca2+-dependent interaction between dCRY and calmodulin (CaM). Through yeast two hybrid, coimmunoprecipitation (Co-IP), nuclear magnetic resonance (NMR) and calorimetric analyses we were able to identify and characterize a CaM binding motif in the dCRY C-terminus. Similarly, we also detailed the CaM binding site of the scaffold protein INAD and demonstrated that CaM bridges dCRY and INAD to form a ternary complex in vivo. Our results suggest a process whereby a rapid dCRY light response stimulates an interaction with INAD, which can be further consolidated by a novel mechanism regulated by CaM.
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Affiliation(s)
| | - Massimo Bellanda
- Department of Chemical Sciences, University of Padova, Padova, Italy
| | | | - Milena Damulewicz
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Faculty of Biology and Earth Sciences, Jagiellonian University, Kraków, Poland
| | - Paola Cusumano
- Department of Biology, University of Padova, Padova, Italy
| | - Simona Aufiero
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Monica Stefani
- Department of Chemical Sciences, University of Padova, Padova, Italy
| | - Barbara Zambelli
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Stefano Mammi
- Department of Chemical Sciences, University of Padova, Padova, Italy
| | - Rodolfo Costa
- Department of Biology, University of Padova, Padova, Italy
| | - Silvio C E Tosatto
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,CNR Institute of Neuroscience, Padova, Italy
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22
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Tarsia C, Danielli A, Florini F, Cinelli P, Ciurli S, Zambelli B. Targeting Helicobacter pylori urease activity and maturation: In-cell high-throughput approach for drug discovery. Biochim Biophys Acta Gen Subj 2018; 1862:2245-2253. [PMID: 30048738 DOI: 10.1016/j.bbagen.2018.07.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [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: 06/04/2018] [Revised: 07/12/2018] [Accepted: 07/18/2018] [Indexed: 02/07/2023]
Abstract
BACKGROUND Helicobacter pylori is a bacterium strongly associated with gastric cancer. It thrives in the acidic environment of the gastric niche of large portions of the human population using a unique adaptive mechanism that involves the catalytic activity of the nickel-dependent enzyme urease. Targeting urease represents a key strategy for drug design and H. pylori eradication. METHOD Here, we describe a novel method to screen, directly in the cellular environment, urease inhibitors. A ureolytic Escherichia coli strain was engineered by cloning the entire urease operon in an expression plasmid and used to test in-cell urease inhibition with a high-throughput colorimetric assay. A two-plasmid system was further developed to evaluate the ability of small peptides to block the protein interactions that lead to urease maturation. RESULTS The developed assay is a robust cellular model to test, directly in the cell environment, urease inhibitors. The efficacy of a co-expressed peptide to affect the interaction between UreF and UreD, two accessory proteins necessary for urease activation, was observed. This event involves a process that occurs through folding upon binding, pointing to the importance of intrinsically disordered hot spots in protein interfaces. CONCLUSIONS The developed system allows the concomitant screening of a large number of drug candidates that interfere with the urease activity both at the level of the enzyme catalysis and maturation. GENERAL SIGNIFICANCE As inhibition of urease has the potential of being a global antibacterial strategy for a large number of infections, this work paves the way for the development of new candidates for antibacterial drugs.
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Affiliation(s)
- Cinzia Tarsia
- Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy
| | - Alberto Danielli
- Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy
| | - Francesca Florini
- Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy
| | - Paolo Cinelli
- Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy
| | - Stefano Ciurli
- Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy
| | - Barbara Zambelli
- Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy.
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23
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Timm J, Brochier-Armanet C, Perard J, Zambelli B, Ollagnier-de-Choudens S, Ciurli S, Cavazza C. The CO dehydrogenase accessory protein CooT is a novel nickel-binding protein. Metallomics 2018; 9:575-583. [PMID: 28447092 DOI: 10.1039/c7mt00063d] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In Rhodospirillum rubrum, maturation of Carbon Monoxide Dehydrogenase (CODH) requires three accessory proteins, CooC, CooT and CooJ, dedicated to nickel insertion into the active site, which is constituted by a distorted [NiFe3S4] cubane coordinated with a mononuclear Fe site. CooC is an ATPase proposed to provide the energy required for the maturation process, while CooJ is described as a metallochaperone with 16 histidines and 2 cysteines at the C-terminus, likely involved in metal binding and/or storage. Prior to the present study, no information was available on CooT at the molecular level. Here, the X-ray structure of RrCooT was obtained, which revealed that this protein is a homodimer featuring a fold that resembles an Sm-like domain, suggesting a role in RNA metabolism that was however not supported by experimental observations. Biochemical and biophysical evidence based on circular dichroism spectroscopy, light scattering, isothermal titration calorimetry and site-directed mutagenesis showed that RrCooT specifically binds a single Ni(ii) per dimer, with a dissociation constant of 9 nM, through the pair of Cys2, highly conserved residues, located at the dimer interface. Despite its role in the activation of RrCODH in vivo, CooT was thought to be a unique protein, found only in R. rubrum, with an unclear function. In this study, we extended the biological impact of CooT, establishing that this protein is a member of a novel Ni(ii)-binding protein family with 111 homologues, linked to anaerobic metabolism in bacteria and archaea, and in most cases to the presence of CODH.
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Affiliation(s)
- J Timm
- Université Grenoble Alpes, Laboratoire de Chimie et Biologie des Métaux, BioCat, F-Grenoble, France
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24
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Broll V, Martinelli AHS, Lopes FC, Fruttero LL, Zambelli B, Salladini E, Dobrovolska O, Ciurli S, Carlini CR. Structural analysis of the interaction between Jaburetox, an intrinsically disordered protein, and membrane models. Colloids Surf B Biointerfaces 2017; 159:849-860. [DOI: 10.1016/j.colsurfb.2017.08.053] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 08/24/2017] [Accepted: 08/27/2017] [Indexed: 01/30/2023]
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25
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Palombo M, Bonucci A, Etienne E, Ciurli S, Uversky VN, Guigliarelli B, Belle V, Mileo E, Zambelli B. The relationship between folding and activity in UreG, an intrinsically disordered enzyme. Sci Rep 2017; 7:5977. [PMID: 28729736 PMCID: PMC5519622 DOI: 10.1038/s41598-017-06330-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 06/12/2017] [Indexed: 12/02/2022] Open
Abstract
A growing body of literature on intrinsically disordered proteins (IDPs) led scientists to rethink the structure-function paradigm of protein folding. Enzymes are often considered an exception to the rule of intrinsic disorder (ID), believed to require a unique structure for catalysis. However, recent studies revealed the presence of disorder in several functional native enzymes. In the present work, we address the importance of dynamics for catalysis, by investigating the relationship between folding and activity in Sporosarcina pasteurii UreG (SpUreG), a P-loop GTPase and the first discovered native ID enzyme, involved in the maturation of the nickel-containing urease. The effect of denaturants and osmolytes on protein structure and activity was analyzed using circular dichroism (CD), Site-Directed Spin Labeling (SDSL) coupled to EPR spectroscopy, and enzymatic assays. Our data show that SpUreG needs a "flexibility window" to be catalytically competent, with both too low and too high mobility being detrimental for its activity.
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Affiliation(s)
- Marta Palombo
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, Bologna, 40127, Italy
| | - Alessio Bonucci
- Aix-Marseille Univ, CNRS, IMM (FR 3479), BIP (UMR 7281), 31 chemin Joseph Aiguier, Marseille, 13402, France
| | - Emilien Etienne
- Aix-Marseille Univ, CNRS, IMM (FR 3479), BIP (UMR 7281), 31 chemin Joseph Aiguier, Marseille, 13402, France
| | - Stefano Ciurli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, Bologna, 40127, Italy
| | - Vladimir N Uversky
- Department of Molecular Medicine, University of South Florida, 12901 Bruce B. Downs Blvd., Tampa, MDC07, USA
| | - Bruno Guigliarelli
- Aix-Marseille Univ, CNRS, IMM (FR 3479), BIP (UMR 7281), 31 chemin Joseph Aiguier, Marseille, 13402, France
| | - Valérie Belle
- Aix-Marseille Univ, CNRS, IMM (FR 3479), BIP (UMR 7281), 31 chemin Joseph Aiguier, Marseille, 13402, France
| | - Elisabetta Mileo
- Aix-Marseille Univ, CNRS, IMM (FR 3479), BIP (UMR 7281), 31 chemin Joseph Aiguier, Marseille, 13402, France.
| | - Barbara Zambelli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, Bologna, 40127, Italy.
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26
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Zambelli B, Uversky VN, Ciurli S. Nickel impact on human health: An intrinsic disorder perspective. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 2016; 1864:1714-1731. [DOI: 10.1016/j.bbapap.2016.09.008] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 08/31/2016] [Accepted: 09/14/2016] [Indexed: 01/26/2023]
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27
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Fabini E, Zambelli B, Mazzei L, Ciurli S, Bertucci C. Surface plasmon resonance and isothermal titration calorimetry to monitor the Ni(II)-dependent binding of Helicobacter pylori NikR to DNA. Anal Bioanal Chem 2016; 408:7971-7980. [DOI: 10.1007/s00216-016-9894-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 07/28/2016] [Accepted: 08/17/2016] [Indexed: 02/03/2023]
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28
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Roncarati D, Pelliciari S, Doniselli N, Maggi S, Vannini A, Valzania L, Mazzei L, Zambelli B, Rivetti C, Danielli A. Metal-responsive promoter DNA compaction by the ferric uptake regulator. Nat Commun 2016; 7:12593. [PMID: 27558202 PMCID: PMC5007355 DOI: 10.1038/ncomms12593] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 07/13/2016] [Indexed: 01/09/2023] Open
Abstract
Short-range DNA looping has been proposed to affect promoter activity in many bacterial species and operator configurations, but only few examples have been experimentally investigated in molecular detail. Here we present evidence for a metal-responsive DNA condensation mechanism controlled by the Helicobacter pylori ferric uptake regulator (Fur), an orthologue of the widespread Fur family of prokaryotic metal-dependent regulators. H. pylori Fur represses the transcription of the essential arsRS acid acclimation operon through iron-responsive oligomerization and DNA compaction, encasing the arsR transcriptional start site in a repressive macromolecular complex. A second metal-dependent regulator NikR functions as nickel-dependent anti-repressor at this promoter, antagonizing the binding of Fur to the operator elements responsible for the DNA condensation. The results allow unifying H. pylori metal ion homeostasis and acid acclimation in a mechanistically coherent model, and demonstrate, for the first time, the existence of a selective metal-responsive DNA compaction mechanism controlling bacterial transcriptional regulation. The Fur protein regulates transcription of bacterial genes in response to metal ions. Here, the authors show that the Fur protein from Helicobacter pylori represses transcription by iron-responsive oligomerization and DNA compaction, encasing the transcriptional start site in a macromolecular complex.
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Affiliation(s)
- Davide Roncarati
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy
| | - Simone Pelliciari
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy
| | - Nicola Doniselli
- Department of Life Sciences, University of Parma, 43124 Parma, Italy
| | - Stefano Maggi
- Department of Life Sciences, University of Parma, 43124 Parma, Italy
| | - Andrea Vannini
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy
| | - Luca Valzania
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy
| | - Luca Mazzei
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy
| | - Barbara Zambelli
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy
| | - Claudio Rivetti
- Department of Life Sciences, University of Parma, 43124 Parma, Italy
| | - Alberto Danielli
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy
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29
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30
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Baraldi E, Coller E, Zoli L, Cestaro A, Tosatto SCE, Zambelli B. Unfoldome variation upon plant-pathogen interactions: strawberry infection by Colletotrichum acutatum. Plant Mol Biol 2015; 89:49-65. [PMID: 26245354 DOI: 10.1007/s11103-015-0353-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 07/26/2015] [Indexed: 06/04/2023]
Abstract
Intrinsically disordered proteins (IDPs) are proteins that lack secondary and/or tertiary structure under physiological conditions. These proteins are very abundant in eukaryotic proteomes and play crucial roles in all molecular mechanisms underlying the response to environmental challenges. In plants, different IDPs involved in stress response have been identified and characterized. Nevertheless, a comprehensive evaluation of protein disorder in plant proteomes under abiotic or biotic stresses is not available so far. In the present work the transcriptome dataset of strawberry (Fragaria X ananassa) fruits interacting with the fungal pathogen Colletotrichum acutatum was actualized onto the woodland strawberry (Fragaria vesca) genome. The obtained cDNA sequences were translated into protein sequences, which were subsequently subjected to disorder analysis. The results, providing the first estimation of disorder abundance associated to plant infection, showed that the proteome activated in the strawberry red fruit during the active fungal propagation is remarkably depleted in disorder. On the other hand, in the resistant white fruit, no significant disorder reduction is observed in the proteins expressed in response to fungal infection. Four representative proteins, FvSMP, FvPRKRIP, FvPCD-4 and FvFAM32A-like, predicted as mainly disordered and never experimentally characterized before, were isolated, and the absence of structure was validated at the secondary and tertiary level using circular dichroism and differential scanning fluorimetry. Their quaternary structure was also established using light scattering. The results are discussed considering the role of protein disorder in plant defense.
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Affiliation(s)
- Elena Baraldi
- Department of Agricultural Sciences, University of Bologna, Bologna, Italy
| | - Emanuela Coller
- Research and Innovation Centre, Foundation Edmund Mach (FEM), San Michele all' Adige, Trento, Italy
- Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Lisa Zoli
- Department of Agricultural Sciences, University of Bologna, Bologna, Italy
| | - Alessandro Cestaro
- Research and Innovation Centre, Foundation Edmund Mach (FEM), San Michele all' Adige, Trento, Italy
| | | | - Barbara Zambelli
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy.
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31
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Mazzei L, Dobrovolska O, Musiani F, Zambelli B, Ciurli S. On the interaction of Helicobacter pylori NikR, a Ni(II)-responsive transcription factor, with the urease operator: in solution and in silico studies. J Biol Inorg Chem 2015. [PMID: 26204982 DOI: 10.1007/s00775-015-1284-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Helicobacter pylori (Hp) is a carcinogen that relies on Ni(II) to survive in the extreme pH conditions of the human guts. The regulation of genes coding for Ni(II) enzymes and proteins is effected by the nickel-responsive transcription factor NikR, composed of a DNA-binding domain (DBD) and a metal-binding domain (MBD). The scope of this study is to obtain the molecular details of the HpNikR interaction with the urease operator OP ureA , in solution. The size of the full-length protein prevents the characterization of the HpNikR-OP ureA interaction using NMR. We thus investigated the two separate domains of HpNikR. The conservation of their oligomeric state was established by multiple-angle light scattering. Isothermal calorimetric titrations indicated that the thermodynamics of Ni(II) binding to the isolated MBD is independent of the presence of the adjacent DBDs. The NMR spectra of the isolated DBD support considerable conservation of its structural properties. The spectral perturbations induced on the DBD by OP ureA provided information useful to calculate a structural model of the HpNikR-OP ureA complex using a docking computational protocol. The NMR assignment of the residues involved in the protein-DNA interaction represents a starting point for the development of drugs potentially able to eradicate H. pylori infections. All evidences so far collected, in this and previous studies, consistently indicate that binding of Ni(II) to the MBD increases the HpNikR-DNA affinity by modulating the dynamic, and not the structural, properties of the protein, suggesting that the formation of a stable complex relies upon an induced fit mechanism.
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Affiliation(s)
- Luca Mazzei
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Bologna, 40127, Italy
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32
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Miraula M, Ciurli S, Zambelli B. Intrinsic disorder and metal binding in UreG proteins from Archae hyperthermophiles: GTPase enzymes involved in the activation of Ni(II) dependent urease. J Biol Inorg Chem 2015; 20:739-55. [PMID: 25846143 DOI: 10.1007/s00775-015-1261-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 03/20/2015] [Indexed: 02/03/2023]
Abstract
Urease is a Ni(II) enzyme present in every domain of life, in charge for nitrogen recycling through urea hydrolysis. Its activity requires the presence of two Ni(II) ions in the active site. These are delivered by the concerted action of four accessory proteins, named UreD, UreF, UreG and UreE. This process requires protein flexibility at different levels and some disorder-to-order transition events that coordinate the mechanism of protein-protein interaction. In particular, UreG, the GTPase in charge of nucleotide hydrolysis required for urease activation, presents a significant degree of intrinsic disorder, existing as a conformational ensemble featuring characteristics that recall a molten globule. Here, the folding properties of UreG were explored in Archaea hyperthermophiles, known to generally feature significantly low level of structural disorder in their proteome. UreG proteins from Methanocaldococcus jannaschii (Mj) and Metallosphaera sedula (Ms) were structurally and functionally analyzed by integrating circular dichroism, NMR, light scattering and enzymatic assays. Metal-binding properties were studied using isothermal titration calorimetry. The results indicate that, as the mesophilic counterparts, both proteins contain a significant amount of secondary structure but maintain a flexible fold and a low GTPase activity. As opposed to other UreGs, secondary structure is lost at high temperatures (68 and 75 °C, respectively) with an apparent two-state mechanism. Both proteins bind Zn(II) and Ni(II), with affinities two orders of magnitude higher for Zn(II) than for Ni(II). No major modifications of the average conformational ensemble are observed, but binding of Zn(II) yields a more compact dimeric form in MsUreG.
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Affiliation(s)
- Manfredi Miraula
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale Giuseppe Fanin 40, 40127, Bologna, Italy
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33
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Lopes FC, Dobrovolska O, Real-Guerra R, Broll V, Zambelli B, Musiani F, Uversky VN, Carlini CR, Ciurli S. Pliable natural biocide: Jaburetox is an intrinsically disordered insecticidal and fungicidal polypeptide derived from jack bean urease. FEBS J 2015; 282:1043-64. [DOI: 10.1111/febs.13201] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 01/13/2015] [Accepted: 01/14/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Fernanda C. Lopes
- Graduate Program in Cellular and Molecular Biology - Center of Biotechnology; Federal University of Rio Grande do Sul; Porto Alegre Brazil
| | - Olena Dobrovolska
- Laboratory of Bioinorganic Chemistry; Department of Pharmacy and Biotechnology; University of Bologna; Italy
| | - Rafael Real-Guerra
- Department of Biophysics and Center of Biotechnology; Federal University of Rio Grande do Sul; Porto Alegre Brazil
| | - Valquiria Broll
- Graduate Program in Cellular and Molecular Biology - Center of Biotechnology; Federal University of Rio Grande do Sul; Porto Alegre Brazil
| | - Barbara Zambelli
- Laboratory of Bioinorganic Chemistry; Department of Pharmacy and Biotechnology; University of Bologna; Italy
| | - Francesco Musiani
- Laboratory of Bioinorganic Chemistry; Department of Pharmacy and Biotechnology; University of Bologna; Italy
| | - Vladimir N. Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute; Morsani College of Medicine; University of South Florida; Tampa USA
- Institute for Biological Instrumentation; Russian Academy of Sciences; Pushchino Moscow Region Russia
- Department of Biological Science; Faculty of Science; King Abdulaziz University; Jeddah Saudi Arabia
| | - Célia R. Carlini
- Graduate Program in Cellular and Molecular Biology - Center of Biotechnology; Federal University of Rio Grande do Sul; Porto Alegre Brazil
- Department of Biophysics and Center of Biotechnology; Federal University of Rio Grande do Sul; Porto Alegre Brazil
- Instituto do Cérebro; Pontifícia Universidade Católica do Rio Grande do Sul; Porto Alegre Brazil
| | - Stefano Ciurli
- Laboratory of Bioinorganic Chemistry; Department of Pharmacy and Biotechnology; University of Bologna; Italy
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34
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Abstract
The structural features, metal coordination modes and metal binding thermodynamics of known Ni(ii)-dependent transcriptional regulators are highlighted and discussed.
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Affiliation(s)
- Francesco Musiani
- Laboratory of Bioinorganic Chemistry
- Department of Pharmacy and Biotechnology
- University of Bologna
- 40127 Bologna, Italy
| | - Barbara Zambelli
- Laboratory of Bioinorganic Chemistry
- Department of Pharmacy and Biotechnology
- University of Bologna
- 40127 Bologna, Italy
| | - Micaela Bazzani
- Laboratory of Bioinorganic Chemistry
- Department of Pharmacy and Biotechnology
- University of Bologna
- 40127 Bologna, Italy
| | - Luca Mazzei
- Laboratory of Bioinorganic Chemistry
- Department of Pharmacy and Biotechnology
- University of Bologna
- 40127 Bologna, Italy
| | - Stefano Ciurli
- Laboratory of Bioinorganic Chemistry
- Department of Pharmacy and Biotechnology
- University of Bologna
- 40127 Bologna, Italy
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35
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Lebrette H, Brochier-Armanet C, Zambelli B, de Reuse H, Borezée-Durant E, Ciurli S, Cavazza C. Promiscuous nickel import in human pathogens: structure, thermodynamics, and evolution of extracytoplasmic nickel-binding proteins. Structure 2014; 22:1421-32. [PMID: 25199691 DOI: 10.1016/j.str.2014.07.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 06/16/2014] [Accepted: 07/13/2014] [Indexed: 10/24/2022]
Abstract
In human pathogenic bacteria, nickel is required for the activation of two enzymes, urease and [NiFe]-hydrogenase, necessary for host infection. Acquisition of Ni(II) is mediated by either permeases or ABC-importers, the latter including a subclass that involves an extracytoplasmic nickel-binding protein, Ni-BP. This study reports on the structure of three Ni-BPs from a diversity of human pathogens and on the existence of three new nickel-binding motifs. These are different from that previously described for Escherichia coli Ni-BP NikA, known to bind nickel via a nickelophore, and indicate a variegated ligand selectivity for Ni-BPs. The structures are consistent with ligand affinities measured in solution by calorimetry and challenge the hypothesis of a general requirement of nickelophores for nickel uptake by canonical ABC importers. Phylogenetic analyses showed that Ni-BPs have different evolutionary origins and emerged independently from peptide-binding proteins, possibly explaining the promiscuous behavior of this class of Ni(II) carriers.
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Affiliation(s)
- Hugo Lebrette
- University Grenoble Alpes, Institut de Biologie Structurale (IBS), 38044 Grenoble, France; CNRS, IBS, 38044 Grenoble, France; CEA, IBS, 38044 Grenoble, France
| | - Céline Brochier-Armanet
- Université de Lyon, Université Lyon 1, CNRS, UMR5558, Laboratoire de Biométrie et Biologie Evolutive, 43 Boulevard du 11 Novembre 1918, 69622 Villeurbanne, France
| | - Barbara Zambelli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale Giuseppe Fanin, 40, 40127 Bologna, Italy
| | - Hilde de Reuse
- Département de Microbiologie, Unité Pathogenèse de Helicobacter, Institut Pasteur, 75724 Paris Cedex 15, France
| | - Elise Borezée-Durant
- INRA, UMR 1319 Micalis, 78350 Jouy en Josas, France; Agro ParisTech, UMR Micalis, 78350 Jouy en Josas, France
| | - Stefano Ciurli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale Giuseppe Fanin, 40, 40127 Bologna, Italy.
| | - Christine Cavazza
- University Grenoble Alpes, LCBM, 17, Avenue des Martyrs, 38054 Grenoble Cedex 09, France.
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Merloni A, Dobrovolska O, Zambelli B, Agostini F, Bazzani M, Musiani F, Ciurli S. Molecular landscape of the interaction between the urease accessory proteins UreE and UreG. Biochim Biophys Acta 2014; 1844:1662-74. [PMID: 24982029 DOI: 10.1016/j.bbapap.2014.06.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 06/12/2014] [Accepted: 06/19/2014] [Indexed: 01/07/2023]
Abstract
Urease, the most efficient enzyme so far discovered, depends on the presence of nickel ions in the catalytic site for its activity. The transformation of inactive apo-urease into active holo-urease requires the insertion of two Ni(II) ions in the substrate binding site, a process that involves the interaction of four accessory proteins named UreD, UreF, UreG and UreE. This study, carried out using calorimetric and NMR-based structural analysis, is focused on the interaction between UreE and UreG from Sporosarcina pasteurii, a highly ureolytic bacterium. Isothermal calorimetric protein-protein titrations revealed the occurrence of a binding event between SpUreE and SpUreG, entailing two independent steps with positive cooperativity (Kd1=42±9μM; Kd2=1.7±0.3μM). This was interpreted as indicating the formation of the (UreE)2(UreG)2 hetero-oligomer upon binding of two UreG monomers onto the pre-formed UreE dimer. The molecular details of this interaction were elucidated using high-resolution NMR spectroscopy. The occurrence of SpUreE chemical shift perturbations upon addition of SpUreG was investigated and analyzed to establish the protein-protein interaction site. The latter appears to involve the Ni(II) binding site as well as mobile portions on the C-terminal and the N-terminal domains. Docking calculations based on the information obtained from NMR provided a structural basis for the protein-protein contact site. The high sequence and structural similarity within these protein classes suggests a generality of the interaction mode among homologous proteins. The implications of these results on the molecular details of the urease activation process are considered and analyzed.
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Affiliation(s)
- Anna Merloni
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Italy
| | - Olena Dobrovolska
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Italy
| | - Barbara Zambelli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Italy
| | - Federico Agostini
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Italy
| | - Micaela Bazzani
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Italy
| | - Francesco Musiani
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Italy
| | - Stefano Ciurli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Italy.
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Abstract
Isothermal titration calorimetry (ITC) is a well-described technique that measures the heat released or absorbed during a chemical reaction, using it as an intrinsic probe to characterize virtually every chemical process. Nowadays, this technique is extensively applied to determine thermodynamic parameters of biomolecular binding equilibria. In addition, ITC has been demonstrated to be able of directly measuring kinetics and thermodynamic parameters (kcat, KM, ΔH) of enzymatic reactions, even though this application is still underexploited. As heat changes spontaneously occur during enzymatic catalysis, ITC does not require any modification or labeling of the system under analysis and can be performed in solution. Moreover, the method needs little amount of material. These properties make ITC an invaluable, powerful and unique tool to study enzyme kinetics in several applications, such as, for example, drug discovery. In this work an experimental ITC-based method to quantify kinetics and thermodynamics of enzymatic reactions is thoroughly described. This method is applied to determine kcat and KM of the enzymatic hydrolysis of urea by Canavalia ensiformis (jack bean) urease. Calculation of intrinsic molar enthalpy (ΔHint) of the reaction is performed. The values thus obtained are consistent with previous data reported in literature, demonstrating the reliability of the methodology.
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Affiliation(s)
- Luca Mazzei
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna
| | - Stefano Ciurli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna
| | - Barbara Zambelli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna;
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Zambelli B, Berardi A, Martin-Diaconescu V, Mazzei L, Musiani F, Maroney MJ, Ciurli S. Nickel binding properties of Helicobacter pylori UreF, an accessory protein in the nickel-based activation of urease. J Biol Inorg Chem 2014; 19:319-34. [PMID: 24292245 PMCID: PMC3943961 DOI: 10.1007/s00775-013-1068-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 11/14/2013] [Indexed: 02/08/2023]
Abstract
Helicobacter pylori UreF (HpUreF) is involved in the insertion of Ni(2+) in the urease active site. The recombinant protein in solution is a dimer characterized by an extensive α-helical structure and a well-folded tertiary structure. HpUreF binds two Ni(2+) ions per dimer, with a micromolar dissociation constant, as shown by calorimetry. X-ray absorption spectroscopy indicated that the Ni(2+) ions reside in a five-coordinate pyramidal geometry comprising exclusively N/O-donor ligands derived from the protein, including one or two histidine imidazole and carboxylate ligands. Binding of Ni(2+) does not affect the solution properties of the protein. Mutation to alanine of His229 and/or Cys231, a pair of residues located on the protein surface that interact with H. pylori UreD, altered the affinity of the protein for Ni(2+). This result, complemented by the findings from X-ray absorption spectroscopy, indicates that the Ni(2+) binding site involves His229, and that Cys231 has an indirect structural role in metal binding. An in vivo assay of urease activation demonstrated that H229A HpUreF, C231A HpUreF, and H229/C231 HpUreF are significantly less competent in this process, suggesting a role for a Ni(2+) complex with UreF in urease maturation. This hypothesis was supported by calculations revealing the presence of a tunnel that joins the Cys-Pro-His metal binding site on UreG and an opening on the UreD surface, passing through UreF close to His229 and Cys231, in the structure of the H. pylori UreDFG complex. This tunnel could be used to transfer nickel into the urease active site during apoenzyme-to-holoenzyme activation.
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Affiliation(s)
- Barbara Zambelli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, 40127 Bologna (Italy)
| | - Andrea Berardi
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, 40127 Bologna (Italy)
| | | | - Luca Mazzei
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, 40127 Bologna (Italy)
| | - Francesco Musiani
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, 40127 Bologna (Italy)
- International School for Advanced Studies (Sissa/ISAS), Trieste (Italy)
| | - Michael J. Maroney
- Department of Chemistry, University of Massachusetts, Amherst 01003, MA, USA
| | - Stefano Ciurli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, 40127 Bologna (Italy)
- Center for Magnetic Resonance (CERM), University of Florence (Italy)
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Abstract
This review focuses on the impact of nickel on human health. In particular, the dual nature of nickel as an essential as well as toxic element in nature is described, and the main forms of nickel that can come in contact with living systems from natural sources and anthropogenic activities are discussed. Concomitantly, the main routes of nickel uptake and transport in humans are covered, and the potential dangers that nickel exposure can represent for health are described. In particular, the insurgence of nickel-derived allergies, nickel-induced carcinogenesis as well as infectious diseases caused by human pathogens that rely on nickel-based enzymes to colonize the host are reviewed at different levels, from their macroscopic aspects on human health to the molecular mechanisms underlying these points. Finally, the importance of nickel as a beneficial element for human health, especially being essential for microorganisms that colonize the human guts, is examined.
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Affiliation(s)
- Barbara Zambelli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy,
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40
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Bergdale TE, Pinkelman RJ, Hughes SR, Zambelli B, Ciurli S, Bang SS. Engineered biosealant strains producing inorganic and organic biopolymers. J Biotechnol 2012; 161:181-9. [DOI: 10.1016/j.jbiotec.2012.07.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2012] [Revised: 06/27/2012] [Accepted: 07/02/2012] [Indexed: 11/28/2022]
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Real-Guerra R, Staniscuaski F, Zambelli B, Musiani F, Ciurli S, Carlini CR. Biochemical and structural studies on native and recombinant Glycine max UreG: a detailed characterization of a plant urease accessory protein. Plant Mol Biol 2012; 78:461-475. [PMID: 22271305 DOI: 10.1007/s11103-012-9878-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Accepted: 01/03/2012] [Indexed: 05/31/2023]
Abstract
Urea is the nitrogen fertilizer most utilized in crop production worldwide. Understanding all factors involved in urea metabolism in plants is an essential step towards assessing and possibly improving the use of urea by plants. Urease, the enzyme responsible for urea hydrolysis, and its accessory proteins, necessary for nickel incorporation into the enzyme active site and concomitant activation, have been extensively characterized in bacteria. In contrast, little is known about their plant counterparts. This work reports a detailed characterization of Glycine max UreG (GmUreG), a urease accessory protein. Two forms of native GmUreG, purified from seeds, were separated by metal affinity chromatography, and their properties (GTPase activity in absence and presence of Ni(2+) or Zn(2+), secondary structure and metal content) were compared with the recombinant protein produced in Escherichia coli. The binding affinity of recombinant GmUreG (rGmUreG) for Ni(2+) and Zn(2+) was determined by isothermal titration calorimetry. rGmUreG binds Zn(2+) or Ni(2+) differently, presenting a very tight binding site for Zn(2+) (K (d) = 0.02 ± 0.01 μM) but not for Ni(2+), thus suggesting that Zn(2+) may play a role on the plant urease assembly process, as suggested for bacteria. Size exclusion chromatography showed that Zn(2+) stabilizes a dimeric form of the rGmUreG, while NMR measurements indicate that rGmUreG belongs to the class of intrinsically disordered proteins. A homology model for the fully folded GmUreG was built and compared to bacterial UreG models, and the possible sites of interaction with other accessory proteins were investigated.
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Affiliation(s)
- Rafael Real-Guerra
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, Porto Alegre, RS 91501-970, Brazil.
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Zambelli B, Cremades N, Neyroz P, Turano P, Uversky VN, Ciurli S. Insights in the (un)structural organization of Bacillus pasteurii UreG, an intrinsically disordered GTPase enzyme. Mol Biosyst 2011; 8:220-8. [PMID: 21922108 DOI: 10.1039/c1mb05227f] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
In the past, enzymatic activity has always been expected to be dependent on overall protein rigidity, necessary for substrate recognition and optimal orientation. However, increasing evidence is now accumulating, revealing that some proteins characterized by intrinsic disorder are actually able to perform catalysis. Among them, the only known natural intrinsically disordered enzyme is UreG, a GTPase that, in plants and bacteria, is involved in the protein interaction network leading to Ni(2+) ions delivery into the active site of urease. In this paper, we report a detailed analysis of the unfolding behaviour of UreG from Bacillus pasteurii (BpUreG), following its thermal and chemical denaturation with a combination of fluorescence spectroscopy, calorimetry, CD and NMR. The results demonstrate that BpUreG exists as an ensemble of inter-converting conformations, whose degrees of secondary structure depend on temperature and denaturant concentration. In particular, three major types of conformational ensembles with different degrees of residual structure were identified, with major structural characteristics resembling those of a molten globule (low temperature, absence of denaturant), pre-molten globule (high temperature, absence or presence of denaturant) and random coil (low temperature, presence of denaturant). Transitions among these ensembles of conformational states occur non-cooperatively although reversibly, with a gradual loss or acquisition of residual structure depending on the conditions. A possible role of disorder in the biological function of UreG is envisaged and discussed.
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Affiliation(s)
- Barbara Zambelli
- Laboratory of Bioinorganic Chemistry, University of Bologna, Bologna, Italy.
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Abstract
Transition metals are both essential to enzymatic catalysis and limited in environmental availability. These two biological facts have together driven organisms to evolve mechanisms for selective metal ion sensing and utilization. Changes in metal ion concentrations are perceived by metal-dependent transcription factors and transduced into appropriate cellular responses, which regulate the machineries of competitive metal ion homeostasis and metallo-enzyme activation. The intrinsic toxicity of the majority of metal ions further creates a need for regulated intracellular trafficking, which is carried out by specific chaperones. The Ni(2+)-dependent urease enzymatic system serves as a paradigm for studying the strategies that cells use to handle an essential, yet toxic, metal ion. Although the discovery of urease as the first biological system for which nickel is essential for activity dates to 1975, the rationale for Ni(2+) selection, as well as the cascade of events involving metal-dependent gene regulation and protein-protein interactions leading to enzyme activation, have yet to be fully unraveled. The past 14 years since the Account by Hausinger and co-workers (Karplus, P. A.; Pearson, M. A.; Hausinger, R. P. Acc. Chem. Res. 1997, 30, 330-337) have witnessed impressive achievements in the understanding of the biological chemistry of Ni(2+) in the urease system. In our Account, we discuss more recent advances in the comprehension of the specific role of Ni(2+) in the catalysis and the interplay between Ni(2+) and other metal ions, such as Zn(2+) and Fe(2+), in the metal-dependent enzyme activity. Our discussion focuses on work carried out in our laboratory. In particular, the structural features of the enzyme bound to inhibitors, substrate analogues, and transition state or intermediate analogues have shed light on the catalytic mechanism. Structural and functional information has been correlated to understand the Ni(2+) sensing effected by NikR, a nickel-dependent transcription factor. The urease activation process, involving insertion of Ni(2+) into the urease active site, has been in part dissected and analyzed through the investigation of the molecular properties of the accessory proteins UreD, UreF, and UreG. The intracellular trafficking of Ni(2+) has been rationalized through a deeper understanding of the structural and metal-binding properties of the metallo-chaperone UreE. All the while, a number of key general concepts have been revealed and developed. These include an understanding of (i) the overall ancillary role of Zn(2+) in nickel metabolism, (ii) the intrinsically disordered nature of the GTPase responsible for coupling the energy consumption to the carbon dioxide requirement for the urease activation process, and (iii) the role of the accessory proteins regulating this GTPase activity.
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Affiliation(s)
- Barbara Zambelli
- Laboratory of Bioinorganic Chemistry, University of Bologna, Italy
| | | | - Stefano Benini
- Faculty of Science and Technology, Free University of Bolzano, Italy
| | - Stefano Ciurli
- Laboratory of Bioinorganic Chemistry, University of Bologna, Italy
- CERM (Center of Magnetic Resonance), University of Florence, Italy
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Manet I, Manoli F, Zambelli B, Andreano G, Masi A, Cellai L, Ottani S, Marconi G, Monti S. Complexes of the antitumoral drugs Doxorubicin and Sabarubicin with telomeric G-quadruplex in basket conformation: ground and excited state properties. Photochem Photobiol Sci 2011; 10:1326-37. [PMID: 21655621 DOI: 10.1039/c1pp05065f] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We studied the binding of two anthracycline drugs, Doxorubicin and Sabarubicin, to a model telomeric sequence 5'-d[GGG(TTAGGG)(3)]-3' (21-mer), assuming the basket G-quadruplex (G4) conformation in Na(+)-rich aqueous solution. We used an approach that combines spectroscopic and microcalorimetric techniques to obtain information about ground and excited state properties of the most stable complexes. Both drugs bind to the 21-mer in basket conformation and complexes of 1:1 and 2:1 drug : 21-mer stoichiometry coexist in solution. Binding constants were determined from fluorescence and isothermal titration calorimetry experiments. For both drugs association is driven by enthalpy and disfavoured by entropy in the case of two sequential binding events to different sites. The drug fluorescence is completely quenched in the 1:1 complex, most likely by electron transfer from the guanine system to the anthraquinone moiety, while part of the emission survives in the 2:1 complex. Circular dichroism (CD) of the individual complexes is dominated by the G-quadruplex signal in the UV and by the anthracycline signal in the near-UV and Vis region. The experimental CD spectra combined with conformational calculations at MM level and quantum mechanical calculation of the rotational strength of the electronic transitions afforded information on the binding geometries.
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Affiliation(s)
- Ilse Manet
- Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche, via Gobetti 101, I-40129, Bologna, Italy
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Lee DW, El Khoury Y, Francia F, Zambelli B, Ciurli S, Venturoli G, Hellwig P, Daldal F. Zinc inhibition of bacterial cytochrome bc(1) reveals the role of cytochrome b E295 in proton release at the Q(o) site. Biochemistry 2011; 50:4263-72. [PMID: 21500804 DOI: 10.1021/bi200230e] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The cytochrome (cyt) bc(1) complex (cyt bc(1)) plays a major role in the electrogenic extrusion of protons across the membrane responsible for the proton motive force to produce ATP. Proton-coupled electron transfer underlying the catalysis of cyt bc(1) is generally accepted, but the molecular basis of coupling and associated proton efflux pathway(s) remains unclear. Herein we studied Zn(2+)-induced inhibition of Rhodobacter capsulatus cyt bc(1) using enzyme kinetics, isothermal titration calorimetry (ITC), and electrochemically induced Fourier transform infrared (FTIR) difference spectroscopy with the purpose of understanding the Zn(2+) binding mechanism and its inhibitory effect on cyt bc(1) function. Analogous studies were conducted with a mutant of cyt b, E295, a residue previously proposed to bind Zn(2+) on the basis of extended X-ray absorption fine-structure spectroscopy. ITC analysis indicated that mutation of E295 to valine, a noncoordinating residue, results in a decrease in Zn(2+) binding affinity. The kinetic study showed that wild-type cyt bc(1) and its E295V mutant have similar levels of apparent K(m) values for decylbenzohydroquinone as a substrate (4.9 ± 0.2 and 3.1 ± 0.4 μM, respectively), whereas their K(I) values for Zn(2+) are 8.3 and 38.5 μM, respectively. The calorimetry-based K(D) values for the high-affinity site of cyt bc(1) are on the same order of magnitude as the K(I) values derived from the kinetic analysis. Furthermore, the FTIR signal of protonated acidic residues was perturbed in the presence of Zn(2+), whereas the E295V mutant exhibited no significant change in electrochemically induced FTIR difference spectra measured in the presence and absence of Zn(2+). Our overall results indicate that the proton-active E295 residue near the Q(o) site of cyt bc(1) can bind directly to Zn(2+), resulting in a decrease in the electron transferring activity without changing drastically the redox potentials of the cofactors of the enzyme. We conclude that E295 is involved in proton efflux coupled to electron transfer at the Q(o) site of cyt bc(1).
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Affiliation(s)
- Dong-Woo Lee
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
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Manet I, Manoli F, Zambelli B, Andreano G, Masi A, Cellai L, Monti S. Affinity of the anthracycline antitumor drugs Doxorubicin and Sabarubicin for human telomeric G-quadruplex structures. Phys Chem Chem Phys 2010; 13:540-51. [PMID: 21052579 DOI: 10.1039/c0cp00898b] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Combining various techniques in solution we proved that Doxorubicin, also called Adriamycin, and Sabarubicin, also known as MEN 10755, bind to the human telomeric sequence, 5'-d[GGG(TTAGGG)(3)]-3' (21-mer), assuming a G-quadruplex structure in the presence of K(+). Complexes of drugs with the 21-mer in 1 : 1 and 2 : 1 stoichiometry coexist in solution. Association constants were obtained from titration experiments and confirmed by isothermal titration calorimetry. The fluorescence of the drugs was quenched upon complexation. UV circular dichroism (CD) spectra of the complexes were characterized by the G-quadruplex signal and indicated that drug binding influences the equilibrium between quadruplex conformations. The visible CD spectra were exclusively due to the drug and show differences in the complexation modes of the two drugs. Spectroscopic and thermodynamic parameters of the 1 : 1 complexes point to drug stacking with the G-quadruplex top or bottom tetrad. Thermodynamic data suggests that the binding of the second drug molecule in the 2 : 1 complex may occur in a groove. Complexation caused a small increase in the thermal stability of the G-quadruplex main conformation, shifting T(m) from 62 to 67 °C.
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Affiliation(s)
- Ilse Manet
- Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche, via Piero Gobetti 101, I-40129 Bologna, Italy.
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Marconi G, Mezzina E, Manet I, Manoli F, Zambelli B, Monti S. Stereoselective interaction of ketoprofen enantiomers with β-cyclodextrin: ground state binding and photochemistry. Photochem Photobiol Sci 2010; 10:48-59. [PMID: 20978661 DOI: 10.1039/c0pp00262c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The chiral recognition ability of β-cyclodextrin (β-CyD) vs.S- and R-ketoprofen (KP) enantiomers has been studied by circular dichroism (CD), isothermal titration calorimetry (ITC) and NMR. The association constants of the 1 : 1 complexes obtained from CD and ITC titration experiments resulted to be the same for both enantiomers within the experimental uncertainty. Well differentiated CD spectra were determined for the diastereomeric complexes. Their structure was assessed by molecular mechanics and molecular dynamics calculations combined with quantum mechanical calculation of the induced rotational strengths in the low energy KP:β-CyD associates, upon comparison of the calculated quantities with the corresponding experimental CD. The inclusion geometry is similar for both enantiomers with the aromatic carbonyl inserted in the CyD cavity, the monosubstituted ring close to the primary CyD rim and the carboxylate group exposed to the solvent close to the secondary rim. NMR spectra fully confirmed the geometry of the diastereomeric complexes. Tiny structural differences were sensibly probed by CD and confirmed by 2D ROESY spectra. Photoproduct studies with UV absorption and MS detection as well as nanosecond laser flash photolysis evidenced lack of chiral discrimination in the photodecarboxylation of KP within the cavity and formation of a photoaddition product to β-CyD by secondary photochemistry of 3-ethylbenzophenone.
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Affiliation(s)
- Giancarlo Marconi
- Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche, via Piero Gobetti 101, I-40129, Bologna, Italy
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48
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Musiani F, Bertoša B, Magistrato A, Zambelli B, Turano P, Losasso V, Micheletti C, Ciurli S, Carloni P. Computational Study of the DNA-Binding Protein Helicobacter pylori NikR: The Role of Ni2+ 2 Francesco Musiani and Branimir Bertoša contributed equally to the simulations presented here. J Chem Theory Comput 2010; 6:3503-15. [DOI: 10.1021/ct900635z] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Francesco Musiani
- Laboratory of Bioinorganic Chemistry, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy, International School for Advanced Studies (SISSA) and CNR-IOM-DEMOCRITOS National Simulation Center, via Bonomea 265, 34136 Trieste, Italy, Ruder Bošković Institute, Bijeniěka 54, 10000 Zagreb, Croatia, German Research School for Simulation Science, FZ-Jülichand RWTH, Wilhelm-Johnen-Strasse, 52428 Jülich, Germany, Center for Magnetic Resonance (CERM), University of Florence, Via Luigi Sacconi 6, 50019
| | - Branimir Bertoša
- Laboratory of Bioinorganic Chemistry, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy, International School for Advanced Studies (SISSA) and CNR-IOM-DEMOCRITOS National Simulation Center, via Bonomea 265, 34136 Trieste, Italy, Ruder Bošković Institute, Bijeniěka 54, 10000 Zagreb, Croatia, German Research School for Simulation Science, FZ-Jülichand RWTH, Wilhelm-Johnen-Strasse, 52428 Jülich, Germany, Center for Magnetic Resonance (CERM), University of Florence, Via Luigi Sacconi 6, 50019
| | - Alessandra Magistrato
- Laboratory of Bioinorganic Chemistry, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy, International School for Advanced Studies (SISSA) and CNR-IOM-DEMOCRITOS National Simulation Center, via Bonomea 265, 34136 Trieste, Italy, Ruder Bošković Institute, Bijeniěka 54, 10000 Zagreb, Croatia, German Research School for Simulation Science, FZ-Jülichand RWTH, Wilhelm-Johnen-Strasse, 52428 Jülich, Germany, Center for Magnetic Resonance (CERM), University of Florence, Via Luigi Sacconi 6, 50019
| | - Barbara Zambelli
- Laboratory of Bioinorganic Chemistry, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy, International School for Advanced Studies (SISSA) and CNR-IOM-DEMOCRITOS National Simulation Center, via Bonomea 265, 34136 Trieste, Italy, Ruder Bošković Institute, Bijeniěka 54, 10000 Zagreb, Croatia, German Research School for Simulation Science, FZ-Jülichand RWTH, Wilhelm-Johnen-Strasse, 52428 Jülich, Germany, Center for Magnetic Resonance (CERM), University of Florence, Via Luigi Sacconi 6, 50019
| | - Paola Turano
- Laboratory of Bioinorganic Chemistry, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy, International School for Advanced Studies (SISSA) and CNR-IOM-DEMOCRITOS National Simulation Center, via Bonomea 265, 34136 Trieste, Italy, Ruder Bošković Institute, Bijeniěka 54, 10000 Zagreb, Croatia, German Research School for Simulation Science, FZ-Jülichand RWTH, Wilhelm-Johnen-Strasse, 52428 Jülich, Germany, Center for Magnetic Resonance (CERM), University of Florence, Via Luigi Sacconi 6, 50019
| | - Valeria Losasso
- Laboratory of Bioinorganic Chemistry, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy, International School for Advanced Studies (SISSA) and CNR-IOM-DEMOCRITOS National Simulation Center, via Bonomea 265, 34136 Trieste, Italy, Ruder Bošković Institute, Bijeniěka 54, 10000 Zagreb, Croatia, German Research School for Simulation Science, FZ-Jülichand RWTH, Wilhelm-Johnen-Strasse, 52428 Jülich, Germany, Center for Magnetic Resonance (CERM), University of Florence, Via Luigi Sacconi 6, 50019
| | - Cristian Micheletti
- Laboratory of Bioinorganic Chemistry, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy, International School for Advanced Studies (SISSA) and CNR-IOM-DEMOCRITOS National Simulation Center, via Bonomea 265, 34136 Trieste, Italy, Ruder Bošković Institute, Bijeniěka 54, 10000 Zagreb, Croatia, German Research School for Simulation Science, FZ-Jülichand RWTH, Wilhelm-Johnen-Strasse, 52428 Jülich, Germany, Center for Magnetic Resonance (CERM), University of Florence, Via Luigi Sacconi 6, 50019
| | - Stefano Ciurli
- Laboratory of Bioinorganic Chemistry, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy, International School for Advanced Studies (SISSA) and CNR-IOM-DEMOCRITOS National Simulation Center, via Bonomea 265, 34136 Trieste, Italy, Ruder Bošković Institute, Bijeniěka 54, 10000 Zagreb, Croatia, German Research School for Simulation Science, FZ-Jülichand RWTH, Wilhelm-Johnen-Strasse, 52428 Jülich, Germany, Center for Magnetic Resonance (CERM), University of Florence, Via Luigi Sacconi 6, 50019
| | - Paolo Carloni
- Laboratory of Bioinorganic Chemistry, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy, International School for Advanced Studies (SISSA) and CNR-IOM-DEMOCRITOS National Simulation Center, via Bonomea 265, 34136 Trieste, Italy, Ruder Bošković Institute, Bijeniěka 54, 10000 Zagreb, Croatia, German Research School for Simulation Science, FZ-Jülichand RWTH, Wilhelm-Johnen-Strasse, 52428 Jülich, Germany, Center for Magnetic Resonance (CERM), University of Florence, Via Luigi Sacconi 6, 50019
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Zubini P, Zambelli B, Musiani F, Ciurli S, Bertolini P, Baraldi E. The RNA hydrolysis and the cytokinin binding activities of PR-10 proteins are differently performed by two isoforms of the Pru p 1 peach major allergen and are possibly functionally related. Plant Physiol 2009; 150:1235-47. [PMID: 19474212 PMCID: PMC2705045 DOI: 10.1104/pp.109.139543] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Accepted: 05/19/2009] [Indexed: 05/20/2023]
Abstract
PR-10 proteins are a family of pathogenesis-related (PR) allergenic proteins playing multifunctional roles. The peach (Prunus persica) major allergen, Pru p 1.01, and its isoform, Pru p 1.06D, were found highly expressed in the fruit skin at the pit hardening stage, when fruits transiently lose their susceptibility to the fungal pathogen Monilinia spp. To investigate the possible role of the two Pru p 1 isoforms in plant defense, the recombinant proteins were expressed in Escherichia coli and purified. Light scattering experiments and circular dichroism spectroscopy showed that both proteins are monomers in solution with secondary structures typical of PR-10 proteins. Even though the proteins do not display direct antimicrobial activity, they both act as RNases, a function possibly related to defense. The RNase activity is different for the two proteins, and only that of Pru p 1.01 is affected in the presence of the cytokinin zeatin, suggesting a physiological correlation between Pru p 1.01 ligand binding and enzymatic activity. The binding of zeatin to Pru p 1.01 was evaluated using isothermal titration calorimetry, which provided information on the stoichiometry and on the thermodynamic parameters of the interaction. The structural architecture of Pru p 1.01 and Pru p 1.06D was obtained by homology modeling, and the differences in the binding pockets, possibly accounting for the observed difference in binding activity, were evaluated.
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Affiliation(s)
- Paola Zubini
- Department of Agri-Food Protection and Improvement, CRIOF , University of Bologna, 40127 Bologna, Italy
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50
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Zambelli B, Turano P, Musiani F, Neyroz P, Ciurli S. Zn2+-linked dimerization of UreG from Helicobacter pylori, a chaperone involved in nickel trafficking and urease activation. Proteins 2009; 74:222-39. [PMID: 18767150 DOI: 10.1002/prot.22205] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The biosynthesis of the active metal-bound form of the nickel-dependent enzyme urease involves the formation of a lysine-carbamate functional group concomitantly with the delivery of two Ni(2+) ions into the precast active site of the apoenzyme and with GTP hydrolysis. In the urease system, this role is performed by UreG, an accessory protein belonging to the group of homologous P-loop GTPases, often required to complete the biosynthesis of nickel-enzymes. This study is focused on UreG from Helicobacter pylori (HpUreG), a bacterium responsible for gastric ulcers and cancer, infecting large part of the human population, and for which urease is a fundamental virulence factor. The soluble HpUreG was expressed in E. coli and purified to homogeneity. On-line size exclusion chromatography and light scattering indicated that apo-HpUreG exists as a monomer in solution. Circular dichroism, which demonstrated the presence of a well-defined secondary structure, and NMR spectroscopy, which revealed a large number of residues that appear structured on the basis of their backbone amide proton chemical shift dispersion, indicated that, at variance with other UreG proteins so far characterized, this protein is significantly folded in solution. The amino acid sequence of HpUreG is 29% identical to that of HypB from Methanocaldococcus jannaschii, a dimeric zinc-binding GTPase involved in the in vivo assembly of [Ni,Fe]-hydrogenase. A homology-based molecular model of HpUreG was calculated, which allowed us to identify structural and functional features of the protein. Isothermal titration microcalorimetry demonstrated that HpUreG specifically binds 0.5 equivalents of Zn(2+) per monomer (K(d) = 0.33 +/- 0.03 microM), whereas it has 20-fold lower affinity for Ni(2+) (K(d) = 10 +/- 1 microM). Zinc ion binding (but not Ni(2+) binding) causes protein dimerization, as confirmed using light scattering measurements. The structural rearrangement occurring upon Zn(2+)-binding and consequent dimerization was evaluated using circular dichroism and fluorescence spectroscopy. Fully conserved histidine and cysteine residues were identified and their role in zinc binding was verified by site-directed mutagenesis and microcalorimetry. The results are analyzed and discussed with respect to analogous examples of GTPases in nickel metabolism.
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Affiliation(s)
- Barbara Zambelli
- Laboratory of Bioinorganic Chemistry, Department of Agro-Environmental Science and Technology, University of Bologna, Bologna, Italy
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