1
|
Huang Z, Cao L, Yan D. Inflammatory immunity and bacteriological perspectives: A new direction for copper treatment of sepsis. J Trace Elem Med Biol 2024; 84:127456. [PMID: 38692229 DOI: 10.1016/j.jtemb.2024.127456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Revised: 04/11/2024] [Accepted: 04/12/2024] [Indexed: 05/03/2024]
Abstract
Copper is an essential trace element for all aerobic organisms because of its unique biological functions. In recent years, researchers have discovered that copper can induce cell death through various regulatory mechanisms, thereby inducing inflammation. Efforts have also been made to alter the chemical structure of copper to achieve either anticancer or anti-inflammatory effects. The copper ion can exhibit bactericidal effects by interfering with the integrity of the cell membrane and promoting oxidative stress. Sepsis is a systemic inflammatory response caused by infection. Some studies have revealed that copper is involved in the pathophysiological process of sepsis and is closely related to its prognosis. During the infection of sepsis, the body may enhance the antimicrobial effect by increasing the release of copper. However, to avoid copper poisoning, all organisms have evolved copper resistance genes. Therefore, further analysis of the complex relationship between copper and bacteria may provide new ideas and research directions for the treatment of sepsis.
Collapse
Affiliation(s)
- Zhenzhen Huang
- Department of Emergency Medicine,Zhoukou Central Hospital, No.26 Renmin Road, Chuanhui District, Zhoukou, Henan Province 466000, China
| | - Lunfei Cao
- Department of Emergency Medicine,Zhoukou Central Hospital, No.26 Renmin Road, Chuanhui District, Zhoukou, Henan Province 466000, China
| | - Dengfeng Yan
- Department of Emergency Medicine,Zhoukou Central Hospital, No.26 Renmin Road, Chuanhui District, Zhoukou, Henan Province 466000, China..
| |
Collapse
|
2
|
de Oliveira Silva YR, Zheng D, Peters SC, Fisher OS. Stabilization of a Cu-binding site by a highly conserved tryptophan residue. J Inorg Biochem 2024; 253:112501. [PMID: 38342077 DOI: 10.1016/j.jinorgbio.2024.112501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 01/31/2024] [Accepted: 02/01/2024] [Indexed: 02/13/2024]
Abstract
Copper serves as an essential cofactor for nearly all living organisms. There are still many gaps remaining in our knowledge of how Gram-positive bacteria import copper and maintain homeostasis. To obtain a better understanding of how these processes work, here we focus on the ycnKJI operon responsible for regulating copper levels in the Gram-positive bacterium Bacillus subtilis. This operon encodes three Cu-related proteins: a copper-dependent transcriptional repressor (YcnK), a putative copper importer (YcnJ), and a copper-binding protein of unknown function (YcnI). We previously found that YcnI's extracellular Domain of Unknown Function 1775 (DUF1775) houses a monohistidine brace motif that coordinates a single Cu(II) ion. The Cu(II) binding site includes a highly conserved tryptophan residue. Here, we investigate the role of that tryptophan and the ability of the protein to interact with other oxidation states of Cu. We find that YcnI exhibits strong preference for binding Cu in the oxidized Cu(II) state, and that the conserved tryptophan residue is not essential for the interaction. We determine the structure of a tryptophan variant to 1.95 Å resolution that indicates that the tryptophan is needed to stabilize the metal binding interaction, and find that this variant has weaker affinity for Cu(II) than the wild-type protein. Together, these data provide further insights into the DUF1775 domain family and reveal the role of the conserved tryptophan residue.
Collapse
Affiliation(s)
| | - Dia Zheng
- Department of Chemistry, Lehigh University, 6 E Packer Ave, Bethlehem, PA 18015, USA
| | - Stephen C Peters
- Department of Earth and Environmental Sciences, Lehigh University, 1 W Packer Ave, Bethlehem, PA 18015, USA
| | - Oriana S Fisher
- Department of Chemistry, Lehigh University, 6 E Packer Ave, Bethlehem, PA 18015, USA.
| |
Collapse
|
3
|
Roger M, Leone P, Blackburn NJ, Horrell S, Chicano TM, Biaso F, Giudici-Orticoni MT, Abriata LA, Hura GL, Hough MA, Sciara G, Ilbert M. Beyond the coupled distortion model: structural analysis of the single domain cupredoxin AcoP, a green mononuclear copper centre with original features. Dalton Trans 2024; 53:1794-1808. [PMID: 38170898 PMCID: PMC10804444 DOI: 10.1039/d3dt03372d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 11/30/2023] [Indexed: 01/05/2024]
Abstract
Cupredoxins are widely occurring copper-binding proteins with a typical Greek-key beta barrel fold. They are generally described as electron carriers that rely on a T1 copper centre coordinated by four ligands provided by the folded polypeptide. The discovery of novel cupredoxins demonstrates the high diversity of this family, with variations in terms of copper-binding ligands, copper centre geometry, redox potential, as well as biological function. AcoP is a periplasmic cupredoxin belonging to the iron respiratory chain of the acidophilic bacterium Acidithiobacillus ferrooxidans. AcoP presents original features, including high resistance to acidic pH and a constrained green-type copper centre of high redox potential. To understand the unique properties of AcoP, we undertook structural and biophysical characterization of wild-type AcoP and of two Cu-ligand mutants (H166A and M171A). The crystallographic structures, including native reduced AcoP at 1.65 Å resolution, unveil a typical cupredoxin fold. The presence of extended loops, never observed in previously characterized cupredoxins, might account for the interaction of AcoP with physiological partners. The Cu-ligand distances, determined by both X-ray diffraction and EXAFS, show that the AcoP metal centre seems to present both T1 and T1.5 features, in turn suggesting that AcoP might not fit well to the coupled distortion model. The crystal structures of two AcoP mutants confirm that the active centre of AcoP is highly constrained. Comparative analysis with other cupredoxins of known structures, suggests that in AcoP the second coordination sphere might be an important determinant of active centre rigidity due to the presence of an extensive hydrogen bond network. Finally, we show that other cupredoxins do not perfectly follow the coupled distortion model as well, raising the suspicion that further alternative models to describe copper centre geometries need to be developed, while the importance of rack-induced contributions should not be underestimated.
Collapse
Affiliation(s)
- Magali Roger
- CNRS, Aix-Marseille University, Bioenergetic and Protein Engineering Laboratory, BIP UMR 7281, Mediterranean Institute of Microbiology, 13009 Marseille, France.
| | - Philippe Leone
- CNRS, Aix-Marseille University, Laboratoire d'Ingénierie des Systèmes Macromoléculaires, LISM UMR7255, 13009 Marseille, France
| | - Ninian J Blackburn
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, Oregon 97239, USA
| | - Sam Horrell
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, UK
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - Tadeo Moreno Chicano
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, UK
| | - Frédéric Biaso
- CNRS, Aix-Marseille University, Bioenergetic and Protein Engineering Laboratory, BIP UMR 7281, Mediterranean Institute of Microbiology, 13009 Marseille, France.
| | - Marie-Thérèse Giudici-Orticoni
- CNRS, Aix-Marseille University, Bioenergetic and Protein Engineering Laboratory, BIP UMR 7281, Mediterranean Institute of Microbiology, 13009 Marseille, France.
| | - Luciano A Abriata
- Laboratory for Biomolecular Modeling and Protein Purification and Structure Core Facility, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Greg L Hura
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Lab, Berkeley, CA, USA
| | - Michael A Hough
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, UK
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - Giuliano Sciara
- CNRS, Aix-Marseille University, Bioenergetic and Protein Engineering Laboratory, BIP UMR 7281, Mediterranean Institute of Microbiology, 13009 Marseille, France.
- Aix Marseille Univ, INRAE, BBF UMR1163, Biodiversité et Biotechnologie Fongiques, 13288 Marseille, France
| | - Marianne Ilbert
- CNRS, Aix-Marseille University, Bioenergetic and Protein Engineering Laboratory, BIP UMR 7281, Mediterranean Institute of Microbiology, 13009 Marseille, France.
| |
Collapse
|
4
|
Hu YQ, Zeng YX, Du Y, Zhao W, Li HR, Han W, Hu T, Luo W. Comparative genomic analysis of two Arctic Pseudomonas strains reveals insights into the aerobic denitrification in cold environments. BMC Genomics 2023; 24:534. [PMID: 37697269 PMCID: PMC10494350 DOI: 10.1186/s12864-023-09638-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 08/30/2023] [Indexed: 09/13/2023] Open
Abstract
BACKGROUND Biological denitrification has been commonly adopted for the removal of nitrogen from sewage effluents. However, due to the low temperature during winter, microorganisms in the wastewater biological treatment unit usually encounter problems such as slow cell growth and low enzymatic efficiency. Hence, the isolation and screening of cold-tolerant aerobic denitrifying bacteria (ADB) have recently drawn attention. In our previous study, two Pseudomonas strains PMCC200344 and PMCC200367 isolated from Arctic soil demonstrated strong denitrification ability at low temperatures. The two Arctic strains show potential for biological nitrogen removal from sewage in cold environments. However, the genome sequences of these two organisms have not been reported thus far. RESULTS Here, the basic characteristics and genetic diversity of strains PMCC200344 and PMCC200367 were described, together with the complete genomes and comparative genomic results. The genome of Pseudomonas sp. PMCC200344 was composed of a circular chromosome of 6,478,166 bp with a G + C content of 58.60% and contained a total of 5,853 genes. The genome of Pseudomonas sp. PMCC200367 was composed of a circular chromosome of 6,360,061 bp with a G + C content of 58.68% and contained 5,801 genes. Not only prophages but also genomic islands were identified in the two Pseudomonas strains. No plasmids were observed. All genes of a complete set of denitrification pathways as well as various putative cold adaptation and heavy metal resistance genes in the genomes were identified and analyzed. These genes were usually detected on genomic islands in bacterial genomes. CONCLUSIONS These analytical results provide insights into the genomic basis of microbial denitrification in cold environments, indicating the potential of Arctic Pseudomonas strains in nitrogen removal from sewage effluents at low temperatures.
Collapse
Affiliation(s)
- Yong-Qiang Hu
- Key Laboratory for Polar Science, Polar Research Institute of China, Ministry of Natural Resources, Shanghai, 200136, China
| | - Yin-Xin Zeng
- Key Laboratory for Polar Science, Polar Research Institute of China, Ministry of Natural Resources, Shanghai, 200136, China.
- School of Oceanography, Shanghai Jiao Tong University, Shanghai, 200030, China.
| | - Yu Du
- Key Laboratory for Polar Science, Polar Research Institute of China, Ministry of Natural Resources, Shanghai, 200136, China
| | - Wei Zhao
- Key Laboratory for Polar Science, Polar Research Institute of China, Ministry of Natural Resources, Shanghai, 200136, China
| | - Hui-Rong Li
- Key Laboratory for Polar Science, Polar Research Institute of China, Ministry of Natural Resources, Shanghai, 200136, China
| | - Wei Han
- Key Laboratory for Polar Science, Polar Research Institute of China, Ministry of Natural Resources, Shanghai, 200136, China
| | - Ting Hu
- Key Laboratory for Polar Science, Polar Research Institute of China, Ministry of Natural Resources, Shanghai, 200136, China
| | - Wei Luo
- Key Laboratory for Polar Science, Polar Research Institute of China, Ministry of Natural Resources, Shanghai, 200136, China
| |
Collapse
|
5
|
Arrault C, Monneau YR, Martin M, Cantrelle FX, Boll E, Chirot F, Comby Zerbino C, Walker O, Hologne M. The battle for silver binding: How the interplay between the SilE, SilF, and SilB proteins contributes to the silver efflux pump mechanism. J Biol Chem 2023; 299:105004. [PMID: 37394004 PMCID: PMC10407283 DOI: 10.1016/j.jbc.2023.105004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 06/27/2023] [Accepted: 06/28/2023] [Indexed: 07/04/2023] Open
Abstract
The resistance of gram-negative bacteria to silver ions is mediated by a silver efflux pump, which mainly relies on a tripartite efflux complex SilCBA, a metallochaperone SilF and an intrinsically disordered protein SilE. However, the precise mechanism by which silver ions are extruded from the cell and the different roles of SilB, SilF, and SilE remain poorly understood. To address these questions, we employed nuclear magnetic resonance and mass spectrometry to investigate the interplay between these proteins. We first solved the solution structures of SilF in its free and Ag+-bound forms, and we demonstrated that SilB exhibits two silver binding sites in its N and C termini. Conversely to the homologous Cus system, we determined that SilF and SilB interact without the presence of silver ions and that the rate of silver dissociation is eight times faster when SilF is bound to SilB, indicating the formation of a SilF-Ag-SilB intermediate complex. Finally, we have shown that SilE does not bind to either SilF or SilB, regardless of the presence or absence of silver ions, further corroborating that it merely acts as a regulator that prevents the cell from being overloaded with silver. Collectively, we have provided further insights into protein interactions within the sil system that contribute to bacterial resistance to silver ions.
Collapse
Affiliation(s)
- Cyrielle Arrault
- Université de Lyon, CNRS, UCB Lyon1, Institut des Sciences Analytiques, UMR5280, Villeurbanne, France
| | - Yoan Rocky Monneau
- Université de Lyon, CNRS, UCB Lyon1, Institut des Sciences Analytiques, UMR5280, Villeurbanne, France; Department of Structural Biology, St Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Marie Martin
- Université de Lyon, CNRS, UCB Lyon1, Institut des Sciences Analytiques, UMR5280, Villeurbanne, France
| | - François-Xavier Cantrelle
- Université de Lille, CNRS, UMR8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Emmanuelle Boll
- Université de Lille, CNRS, UMR8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Fabien Chirot
- Univ Lyon 1, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, UMR5306, Cité Lyonnaise de l'Environnement et de l'Analyse, Villeurbanne, France
| | - Clothilde Comby Zerbino
- Univ Lyon 1, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, UMR5306, Cité Lyonnaise de l'Environnement et de l'Analyse, Villeurbanne, France
| | - Olivier Walker
- Université de Lyon, CNRS, UCB Lyon1, Institut des Sciences Analytiques, UMR5280, Villeurbanne, France
| | - Maggy Hologne
- Université de Lyon, CNRS, UCB Lyon1, Institut des Sciences Analytiques, UMR5280, Villeurbanne, France.
| |
Collapse
|
6
|
Novoa-Aponte L, Argüello JM. Unique underlying principles shaping copper homeostasis networks. J Biol Inorg Chem 2022; 27:509-528. [PMID: 35802193 PMCID: PMC9470648 DOI: 10.1007/s00775-022-01947-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 05/27/2022] [Indexed: 12/27/2022]
Abstract
Abstract Copper is essential in cells as a cofactor for key redox enzymes. Bacteria have acquired molecular components that sense, uptake, distribute, and expel copper ensuring that cuproenzymes are metallated and steady-state metal levels are maintained. Toward preventing deleterious reactions, proteins bind copper ions with high affinities and transfer the metal via ligand exchange, warranting that copper ions are always complexed. Consequently, the directional copper distribution within cell compartments and across cell membranes requires specific dynamic interactions and metal exchange between cognate holo-apo protein partners. These metal exchange reactions are determined by thermodynamic and kinetics parameters and influenced by mass action. Then, copper distribution can be conceptualized as a molecular system of singular interacting elements that maintain a physiological copper homeostasis. This review focuses on the impact of copper high-affinity binding and exchange reactions on the homeostatic mechanisms, the conceptual models to describe the cell as a homeostatic system, the various molecule functions that contribute to copper homeostasis, and the alternative system architectures responsible for copper homeostasis in model bacteria. Graphical Abstract ![]()
Collapse
Affiliation(s)
- Lorena Novoa-Aponte
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, 60 Prescott St, Worcester, MA, 01605, USA.,Genetics and Metabolism Section, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, 20892, USA
| | - José M Argüello
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, 60 Prescott St, Worcester, MA, 01605, USA.
| |
Collapse
|
7
|
Abstract
Zn2+ ions are essential in many physiological processes, including enzyme catalysis, protein structural stabilization, and the regulation of many proteins. The affinities of proteins for Zn2+ ions span several orders of magnitude, with catalytic Zn2+ ions generally held more tightly than structural or regulatory ones. Metal carrier proteins, most of which are not specific for Zn2+, bind these ions with a broad range of affinities that overlap those of catalytic, structural, and regulatory Zn2+ ions and are thought to be responsible for distributing the metal through most cells, tissues, and fluid compartments. While little is known about how many proteins obtain or release these ions, there is now considerable experimental evidence suggesting that metal carrier proteins may be responsible for transferring metals to and from some Zn2+-dependent proteins, thus serving as a major regulatory factor for them. In this review, the biological roles of Zn2+ and structures of Zn2+ binding sites are examined, and experimental evidence demonstrating the direct participation of metal carrier proteins in enzyme regulation is discussed. Mechanisms of metal ion transfer are also offered, and the potential physiological significance of this phenomenon is explored.
Collapse
|
8
|
Andrei A, Öztürk Y, Khalfaoui-Hassani B, Rauch J, Marckmann D, Trasnea PI, Daldal F, Koch HG. Cu Homeostasis in Bacteria: The Ins and Outs. MEMBRANES 2020; 10:E242. [PMID: 32962054 PMCID: PMC7558416 DOI: 10.3390/membranes10090242] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 09/11/2020] [Accepted: 09/15/2020] [Indexed: 12/16/2022]
Abstract
Copper (Cu) is an essential trace element for all living organisms and used as cofactor in key enzymes of important biological processes, such as aerobic respiration or superoxide dismutation. However, due to its toxicity, cells have developed elaborate mechanisms for Cu homeostasis, which balance Cu supply for cuproprotein biogenesis with the need to remove excess Cu. This review summarizes our current knowledge on bacterial Cu homeostasis with a focus on Gram-negative bacteria and describes the multiple strategies that bacteria use for uptake, storage and export of Cu. We furthermore describe general mechanistic principles that aid the bacterial response to toxic Cu concentrations and illustrate dedicated Cu relay systems that facilitate Cu delivery for cuproenzyme biogenesis. Progress in understanding how bacteria avoid Cu poisoning while maintaining a certain Cu quota for cell proliferation is of particular importance for microbial pathogens because Cu is utilized by the host immune system for attenuating pathogen survival in host cells.
Collapse
Affiliation(s)
- Andreea Andrei
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs Universität Freiburg; Stefan Meier Str. 17, 79104 Freiburg, Germany; (A.A.); (Y.O.); (J.R.); (D.M.)
- Fakultät für Biologie, Albert-Ludwigs Universität Freiburg; Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Yavuz Öztürk
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs Universität Freiburg; Stefan Meier Str. 17, 79104 Freiburg, Germany; (A.A.); (Y.O.); (J.R.); (D.M.)
| | | | - Juna Rauch
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs Universität Freiburg; Stefan Meier Str. 17, 79104 Freiburg, Germany; (A.A.); (Y.O.); (J.R.); (D.M.)
| | - Dorian Marckmann
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs Universität Freiburg; Stefan Meier Str. 17, 79104 Freiburg, Germany; (A.A.); (Y.O.); (J.R.); (D.M.)
| | | | - Fevzi Daldal
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA;
| | - Hans-Georg Koch
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs Universität Freiburg; Stefan Meier Str. 17, 79104 Freiburg, Germany; (A.A.); (Y.O.); (J.R.); (D.M.)
| |
Collapse
|
9
|
Schilling KM, Tao L, Wu B, Kiblen JTM, Ubilla-Rodriguez NC, Pushie MJ, Britt RD, Roseman GP, Harris DA, Millhauser GL. Both N-Terminal and C-Terminal Histidine Residues of the Prion Protein Are Essential for Copper Coordination and Neuroprotective Self-Regulation. J Mol Biol 2020; 432:4408-4425. [PMID: 32473880 PMCID: PMC7387163 DOI: 10.1016/j.jmb.2020.05.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 05/25/2020] [Accepted: 05/26/2020] [Indexed: 01/19/2023]
Abstract
The cellular prion protein (PrPC) comprises two domains: a globular C-terminal domain and an unstructured N-terminal domain. Recently, copper has been observed to drive tertiary contact in PrPC, inducing a neuroprotective cis interaction that structurally links the protein's two domains. The location of this interaction on the C terminus overlaps with the sites of human pathogenic mutations and toxic antibody docking. Combined with recent evidence that the N terminus is a toxic effector regulated by the C terminus, there is an emerging consensus that this cis interaction serves a protective role, and that the disruption of this interaction by misfolded PrP oligomers may be a cause of toxicity in prion disease. We demonstrate here that two highly conserved histidines in the C-terminal domain of PrPC are essential for the protein's cis interaction, which helps to protect against neurotoxicity carried out by its N terminus. We show that simultaneous mutation of these histidines drastically weakens the cis interaction and enhances spontaneous cationic currents in cultured cells, the first C-terminal mutant to do so. Whereas previous studies suggested that Cu2+ coordination was localized solely to the protein's N-terminal domain, we find that both domains contribute equatorially coordinated histidine residue side-chains, resulting in a novel bridging interaction. We also find that extra N-terminal histidines in pathological familial mutations involving octarepeat expansions inhibit this interaction by sequestering copper from the C terminus. Our findings further establish a structural basis for PrPC's C-terminal regulation of its otherwise toxic N terminus.
Collapse
Affiliation(s)
- Kevin M Schilling
- Department of Chemistry and Biochemistry, University of California, 1156 High Street, Santa Cruz, CA 95064, USA
| | - Lizhi Tao
- Department of Chemistry, University of California, 1 Shields Ave., Davis, CA 95616, USA
| | - Bei Wu
- Department of Biochemistry, Boston University School of Medicine, 72 E. Concord St Silvio Conte., Boston, MA 02118, USA
| | - Joseph T M Kiblen
- Department of Chemistry and Biochemistry, University of California, 1156 High Street, Santa Cruz, CA 95064, USA
| | - Natalia C Ubilla-Rodriguez
- Department of Chemistry and Biochemistry, University of California, 1156 High Street, Santa Cruz, CA 95064, USA
| | - M Jake Pushie
- Department of Surgery, College of Medicine, University of Saskatchewan, 107 Wiggins Rd B419, Saskatoon, SK S7N 5E5, Canada
| | - R David Britt
- Department of Chemistry, University of California, 1 Shields Ave., Davis, CA 95616, USA
| | - Graham P Roseman
- Department of Chemistry and Biochemistry, University of California, 1156 High Street, Santa Cruz, CA 95064, USA
| | - David A Harris
- Department of Biochemistry, Boston University School of Medicine, 72 E. Concord St Silvio Conte., Boston, MA 02118, USA.
| | - Glenn L Millhauser
- Department of Chemistry and Biochemistry, University of California, 1156 High Street, Santa Cruz, CA 95064, USA.
| |
Collapse
|
10
|
Hausrath AC, Ramirez NA, Ly AT, McEvoy MM. The bacterial copper resistance protein CopG contains a cysteine-bridged tetranuclear copper cluster. J Biol Chem 2020; 295:11364-11376. [PMID: 32571874 DOI: 10.1074/jbc.ra120.013907] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/08/2020] [Indexed: 01/31/2023] Open
Abstract
CopG is an uncharacterized protein ubiquitous in Gram-negative bacteria whose gene frequently occurs in clusters of copper resistance genes and can be recognized by the presence of a conserved CxCC motif. To investigate its contribution to copper resistance, here we undertook a structural and biochemical characterization of the CopG protein from Pseudomonas aeruginosa Results from biochemical analyses of CopG purified under aerobic conditions indicate that it is a green copper-binding protein that displays absorbance maxima near 411, 581, and 721 nm and is monomeric in solution. Determination of the three-dimensional structure by X-ray crystallography revealed that CopG consists of a thioredoxin domain with a C-terminal extension that contributes to metal binding. We noted that adjacent to the CxCC motif is a cluster of four copper ions bridged by cysteine sulfur atoms. Structures of CopG in two oxidation states support the assignment of this protein as an oxidoreductase. On the basis of these structural and spectroscopic findings and also genetic evidence, we propose that CopG has a role in interconverting Cu(I) and Cu(II) to minimize toxic effects and facilitate export by the Cus RND transporter efflux system.
Collapse
Affiliation(s)
- Andrew C Hausrath
- Institute for Society and Genetics, University of California, Los Angeles, California, USA.,Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Nicholas A Ramirez
- Molecular Biology Institute, University of California, Los Angeles, California, USA
| | - Alan T Ly
- Institute for Society and Genetics, University of California, Los Angeles, California, USA
| | - Megan M McEvoy
- Institute for Society and Genetics, University of California, Los Angeles, California, USA .,Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California, USA.,Molecular Biology Institute, University of California, Los Angeles, California, USA
| |
Collapse
|
11
|
Fleischhacker AS, Gunawan AL, Kochert BA, Liu L, Wales TE, Borowy MC, Engen JR, Ragsdale SW. The heme-regulatory motifs of heme oxygenase-2 contribute to the transfer of heme to the catalytic site for degradation. J Biol Chem 2020; 295:5177-5191. [PMID: 32152224 PMCID: PMC7170523 DOI: 10.1074/jbc.ra120.012803] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 03/03/2020] [Indexed: 11/06/2022] Open
Abstract
Heme-regulatory motifs (HRMs) are present in many proteins that are involved in diverse biological functions. The C-terminal tail region of human heme oxygenase-2 (HO2) contains two HRMs whose cysteine residues form a disulfide bond; when reduced, these cysteines are available to bind Fe3+-heme. Heme binding to the HRMs occurs independently of the HO2 catalytic active site in the core of the protein, where heme binds with high affinity and is degraded to biliverdin. Here, we describe the reversible, protein-mediated transfer of heme between the HRMs and the HO2 core. Using hydrogen-deuterium exchange (HDX)-MS to monitor the dynamics of HO2 with and without Fe3+-heme bound to the HRMs and to the core, we detected conformational changes in the catalytic core only in one state of the catalytic cycle-when Fe3+-heme is bound to the HRMs and the core is in the apo state. These conformational changes were consistent with transfer of heme between binding sites. Indeed, we observed that HRM-bound Fe3+-heme is transferred to the apo-core either upon independent expression of the core and of a construct spanning the HRM-containing tail or after a single turnover of heme at the core. Moreover, we observed transfer of heme from the core to the HRMs and equilibration of heme between the core and HRMs. We therefore propose an Fe3+-heme transfer model in which HRM-bound heme is readily transferred to the catalytic site for degradation to facilitate turnover but can also equilibrate between the sites to maintain heme homeostasis.
Collapse
Affiliation(s)
- Angela S Fleischhacker
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-0606
| | - Amanda L Gunawan
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-0606
| | - Brent A Kochert
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115
| | - Liu Liu
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-0606
| | - Thomas E Wales
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115
| | - Maelyn C Borowy
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-0606
| | - John R Engen
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115
| | - Stephen W Ragsdale
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-0606.
| |
Collapse
|
12
|
Alwan KB, Welch EF, Blackburn NJ. Catalytic M Center of Copper Monooxygenases Probed by Rational Design. Effects of Selenomethionine and Histidine Substitution on Structure and Reactivity. Biochemistry 2019; 58:4436-4446. [PMID: 31626532 DOI: 10.1021/acs.biochem.9b00823] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The M centers of the mononuclear monooxygenases peptidylglycine monooxygenase (PHM) and dopamine β-monooxygenase bind and activate dioxygen en route to substrate hydroxylation. Recently, we reported the rational design of a protein-based model in which the CusF metallochaperone was repurposed via a His to Met mutation to act as a structural and spectroscopic biomimic. The PHM M site exhibits a number of unusual attributes, including a His2Met ligand set, a fluxional Cu(I)-S(Met) bond, tight binding of exogenous ligands CO and N3-, and complete coupling of oxygen reduction to substrate hydroxylation even at extremely low turnover rates. In particular, mutation of the Met ligand to His completely eliminates the catalytic activity despite the propensity of CuI-His3 centers to bind and activate dioxygen in other metalloenzyme systems. Here, we further develop the CusF-based model to explore methionine variants in which Met is replaced by selenomethionine (SeM) and histidine. We examine the effects on coordinate structure and exogenous ligand binding via X-ray absorption spectroscopy and electron paramagnetic resonance and probe the consequences of mutations on redox chemistry via studies of the reduction by ascorbate and oxidation via molecular oxygen. The M-site model is three-coordinate in the Cu(I) state and binds CO to form a four-coordinate carbonyl. In the oxidized forms, the coordination changes to tetragonal five-coordinate with a long axial Met ligand that like the enzymes is undetectable at either the Cu or Se K edges. The EXAFS data at the Se K edge of the SeM variant provide unique information about the nature of the Cu-methionine bond that is likewise weak and fluxional. Kinetic studies document the sluggish reactivity of the Cu(I) complexes with molecular oxygen and rapid rates of reduction of the Cu(II) complexes by ascorbate, indicating a remarkable stability of the Cu(I) state in all three derivatives. The results show little difference between the Met ligand and its SeM and His congeners and suggest that the Met contributes to catalysis in ways that are more complex than simple perturbation of the redox chemistry. Overall, the results stimulate a critical re-examination of the canonical reaction mechanisms of the mononuclear copper monooxygenases.
Collapse
Affiliation(s)
- Katherine B Alwan
- Department of Chemical Physiology and Biochemistry , Oregon Health & Sciences University , Portland , Oregon 97239 , United States
| | - Evan F Welch
- Department of Chemical Physiology and Biochemistry , Oregon Health & Sciences University , Portland , Oregon 97239 , United States
| | - Ninian J Blackburn
- Department of Chemical Physiology and Biochemistry , Oregon Health & Sciences University , Portland , Oregon 97239 , United States
| |
Collapse
|
13
|
Rao G, Alwan KB, Blackburn NJ, Britt RD. Incorporation of Ni 2+, Co 2+, and Selenocysteine into the Auxiliary Fe-S Cluster of the Radical SAM Enzyme HydG. Inorg Chem 2019; 58:12601-12608. [PMID: 31539235 DOI: 10.1021/acs.inorgchem.9b01293] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The radical SAM enzyme HydG generates CO- and CN--containing Fe complexes that are involved in the bioassembly of the [FeFe] hydrogenase active cofactor, the H-cluster. HydG contains a unique 5Fe-4S cluster in which the fifth "dangler" Fe and the coordinating cysteine molecule have both been shown to be essential for its function. Here, we demonstrate that this dangler Fe can be replaced with Ni2+ or Co2+ and that the cysteine can be replaced with selenocysteine. The resulting HydG variants were characterized by electron paramagnetic resonance and X-ray absorption spectroscopy, as well as subjected to a Tyr cleavage assay. Both Ni2+ and Co2+ are shown to be exchange-coupled to the 4Fe-4S cluster, and selenocysteine substitution does not alter the electronic structure significantly. XAS data provide details of the coordination environments near the Ni, Co, and Se atoms and support a close interaction of the dangler metal with the FeS cluster via an asymmetric SeCys bridge. Finally, while we were unable to observe the formation of novel organometallic species for the Ni2+ and Co2+ variants, the selenocysteine variant retains the activity of wild type HydG in forming [Fe(CO)x(CN)y] species. Our results provide more insights into the unique auxiliary cluster in HydG and expand the scope of artificially generated Fe-S clusters with heteroatoms.
Collapse
Affiliation(s)
- Guodong Rao
- Department of Chemistry , University of California , Davis , California 95616 , United States
| | - Katherine B Alwan
- Department of Chemical Physiology and Biochemistry , Oregon Health and Science University , Portland , Oregon 97239 , United States
| | - Ninian J Blackburn
- Department of Chemical Physiology and Biochemistry , Oregon Health and Science University , Portland , Oregon 97239 , United States
| | - R David Britt
- Department of Chemistry , University of California , Davis , California 95616 , United States
| |
Collapse
|
14
|
Neupane DP, Fullam SH, Chacón KN, Yukl ET. Crystal structures of AztD provide mechanistic insights into direct zinc transfer between proteins. Commun Biol 2019; 2:308. [PMID: 31428696 PMCID: PMC6689063 DOI: 10.1038/s42003-019-0542-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 07/15/2019] [Indexed: 12/19/2022] Open
Abstract
Zinc acquisition from limited environments is critical for bacterial survival and pathogenesis. AztD has been identified as a periplasmic or cell surface zinc-binding protein in numerous bacterial species. In Paracoccus denitrificans, AztD can transfer zinc directly to AztC, the solute binding protein for a zinc-specific ATP-binding cassette transporter system, suggesting a role in zinc acquisition and homeostasis. Here, we present the first cry stal structures of AztD from P. denitrificans and tbe human pathogen Citrobacter koseri, revealing a beta-propeller fold and two high-affinity zinc-binding sites that are highly conserved among AztD homologs. These structures combined with transfer assays using WT and mutant proteins provide rare insight into the mechanism of direct zinc transfer from one protein to another. Given the importance of zinc import to bacterial pathogenesis, these insights may prove valuable to the development of zinc transfer inhibitors as antibiotics.
Collapse
Affiliation(s)
- Durga Prasad Neupane
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003 USA
| | - Stephanie Hope Fullam
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003 USA
| | | | - Erik Thomas Yukl
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003 USA
| |
Collapse
|
15
|
Alwan KB, Welch EF, Arias RJ, Gambill BF, Blackburn NJ. Rational Design of a Histidine-Methionine Site Modeling the M-Center of Copper Monooxygenases in a Small Metallochaperone Scaffold. Biochemistry 2019; 58:3097-3108. [PMID: 31243953 DOI: 10.1021/acs.biochem.9b00312] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mononuclear copper monooxygenases peptidylglycine monooxygenase (PHM) and dopamine β-monooxygenase (DBM) catalyze the hydroxylation of high energy C-H bonds utilizing a pair of chemically distinct copper sites (CuH and CuM) separated by 11 Å. In earlier work, we constructed single-site PHM variants that were designed to allow the study of the M- and H-centers independently in order to place their reactivity sequentially along the catalytic pathway. More recent crystallographic studies suggest that these single-site variants may not be truly representative of the individual active sites. In this work, we describe an alternative approach that uses a rational design to construct an artificial PHM model in a small metallochaperone scaffold. Using site-directed mutagenesis, we constructed variants that provide a His2Met copper-binding ligand set that mimics the M-center of PHM. The results show that the model accurately reproduces the chemical and spectroscopic properties of the M-center, including details of the methionine coordination, and the properties of Cu(I) and Cu(II) states in the presence of endogenous ligands such as CO and azide. The rate of reduction of the Cu(II) form of the model by the chromophoric reductant N,N'-dimethyl phenylenediamine (DMPD) has been compared with that of the PHM M-center, and the reaction chemistry of the Cu(I) forms with molecular oxygen has also been explored, revealing an unusually low reactivity toward molecular oxygen. This latter finding emphasizes the importance of substrate triggering of oxygen reactivity and implies that the His2Met ligand set, while necessary, is insufficient on its own to activate oxygen in these enzyme systems.
Collapse
Affiliation(s)
- Katherine B Alwan
- Department of Chemical Physiology and Biochemistry , Oregon Health & Sciences University , Portland , Oregon 97239 , United States
| | - Evan F Welch
- Department of Chemical Physiology and Biochemistry , Oregon Health & Sciences University , Portland , Oregon 97239 , United States
| | - Renee J Arias
- Department of Chemical Physiology and Biochemistry , Oregon Health & Sciences University , Portland , Oregon 97239 , United States
| | - Ben F Gambill
- Department of Chemical Physiology and Biochemistry , Oregon Health & Sciences University , Portland , Oregon 97239 , United States
| | - Ninian J Blackburn
- Department of Chemical Physiology and Biochemistry , Oregon Health & Sciences University , Portland , Oregon 97239 , United States
| |
Collapse
|