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Zheng M, Lin R, Zhu J, Dong Q, Chen J, Jiang P, Zhang H, Liu J, Chen Z. Effector Proteins of Type IV Secretion System: Weapons of Brucella Used to Fight Against Host Immunity. Curr Stem Cell Res Ther 2024; 19:145-153. [PMID: 36809969 DOI: 10.2174/1574888x18666230222124529] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 11/15/2022] [Accepted: 12/29/2022] [Indexed: 02/24/2023]
Abstract
Brucella is an intracellular bacterial pathogen capable of long-term persistence in the host, resulting in chronic infections in livestock and wildlife. The type IV secretion system (T4SS) is an important virulence factor of Brucella and is composed of 12 protein complexes encoded by the VirB operon. T4SS exerts its function through its secreted 15 effector proteins. The effector proteins act on important signaling pathways in host cells, inducing host immune responses and promoting the survival and replication of Brucella in host cells to promote persistent infection. In this article, we describe the intracellular circulation of Brucella-infected cells and survey the role of Brucella VirB T4SS in regulating inflammatory responses and suppressing host immune responses during infection. In addition, the important mechanisms of these 15 effector proteins in resisting the host immune response during Brucella infection are elucidated. For example, VceC and VceA assist in achieving sustained survival of Brucella in host cells by affecting autophagy and apoptosis. BtpB, together with BtpA, controls the activation of dendritic cells during infection, induces inflammatory responses, and controls host immunity. This article reviews the effector proteins secreted by Brucella T4SS and their involvement in immune responses, which can provide a reliable theoretical basis for the subsequent mechanism of hijacking the host cell signaling pathway by bacteria and contribute to the development of better vaccines to effectively treat Brucella bacterial infection.
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Affiliation(s)
- Min Zheng
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, 110866, Shenyang, China
| | - Ruiqi Lin
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, 110866, Shenyang, China
| | - Jinying Zhu
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, 110866, Shenyang, China
| | - Qiao Dong
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, 110866, Shenyang, China
| | - Jingjing Chen
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, 110866, Shenyang, China
| | - Pengfei Jiang
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, 110866, Shenyang, China
| | - Huan Zhang
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, 110866, Shenyang, China
| | - Jinling Liu
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, 110866, Shenyang, China
| | - Zeliang Chen
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, 110866, Shenyang, China
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Nagata H, Yoshimoto M, Walde P. Preparation and Catalytic Properties of Carbonic Anhydrase Conjugated to Liposomes through a Bis-Aryl Hydrazone Bond. ACS OMEGA 2023; 8:18637-18652. [PMID: 37273636 PMCID: PMC10233673 DOI: 10.1021/acsomega.3c00551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 05/05/2023] [Indexed: 06/06/2023]
Abstract
Liposomes (lipid vesicles) with sizes of about 100-200 nm carrying surface-bound (immobilized) water-soluble enzymes are functionalized molecular compartment systems for possible applications, for example, as therapeutic materials or as catalytic reaction units for running reactions in aqueous media in vitro. One way of covalently attaching enzyme molecules under mild conditions in a controlled way to the surface of preformed liposomes is to apply the spectrophotometrically traceable bis-aryl hydrazone (BAH) bond between the liposome and the enzyme molecules of interest. Using bovine carbonic anhydrase (BCA), an aqueous dispersion of liposome-BAH-BCA - conjugates of defined composition was prepared. The liposomes used consisted of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), N-(methylpolyoxyethylene oxycarbonyl)-1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE-PEG), and N-(aminopropylpolyoxyethylene oxycarbonyl)-1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE-PEG-NH2). The amino group of some of the DSPE-PEG-NH2 molecules present in the liposomes were converted into an aromatic aldehyde, which (after purification) reacted with (purified) BCA molecules that had on their surface on average one acetone protected aromatic hydrazine. After purification of the liposome-BAH-BCA conjugate dispersion obtained, it was characterized in terms of (i) BCA activity, (ii) overall BCA structure, and (iii) storage stability. For an average liposome of 138 nm diameter, about 1200 BCA molecules were attached to the outer liposome surface. Liposomally bound BCA was found to exhibit (i) similar catalytic activity at 25 °C and (ii) similar storage stability when stored in a dispersed state in aqueous solution at 4 °C as free BCA. Measurements at 5 °C clearly showed that liposome-BAH-BCA is able to catalyze the hydration of carbon dioxide to hydrogen carbonate.
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Affiliation(s)
- Hikaru Nagata
- Department
of Applied Chemistry, Yamaguchi University, Tokiwadai 2-16-1, Ube 755-8611, Japan
| | - Makoto Yoshimoto
- Department
of Applied Chemistry, Yamaguchi University, Tokiwadai 2-16-1, Ube 755-8611, Japan
| | - Peter Walde
- Department
of Materials, ETH-Zürich, Leopold-Ruzicka-Weg 4, Zürich 8093, Switzerland
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Di Fiore A, De Luca V, Langella E, Nocentini A, Buonanno M, Maria Monti S, Supuran CT, Capasso C, De Simone G. Biochemical, structural, and computational studies of a γ-carbonic anhydrase from the pathogenic bacterium Burkholderia pseudomallei. Comput Struct Biotechnol J 2022; 20:4185-4194. [PMID: 36016712 PMCID: PMC9389205 DOI: 10.1016/j.csbj.2022.07.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 07/18/2022] [Accepted: 07/19/2022] [Indexed: 11/09/2022] Open
Abstract
Melioidosis is a severe disease caused
Burkholderia pseudomallei. γ-carbonic anhydrases (γ-CAs) have been recently
introduced as novel antibacterial drug targets. A new γ-CA from B.
pseudomallei has been investigated by a
multidisciplinary approach. Obtained results provide an important starting point
for developing new anti-melioidosis drugs.
Melioidosis is a severe disease caused by the highly
pathogenic gram-negative bacterium Burkholderia
pseudomallei. Several studies have highlighted the broad
resistance of this pathogen to many antibiotics and pointed out the pivotal
importance of improving the pharmacological arsenal against it. Since γ-carbonic
anhydrases (γ-CAs) have been recently introduced as potential and novel
antibacterial drug targets, in this paper, we report a detailed characterization
of BpsγCA, a γ-CA from B.
pseudomallei by a multidisciplinary approach. In
particular, the enzyme was recombinantly produced and biochemically
characterized. Its catalytic activity at different pH values was measured, the
crystal structure was determined and theoretical pKa calculations were carried
out. Results provided a snapshot of the enzyme active site and dissected the
role of residues involved in the catalytic mechanism and ligand recognition.
These findings are an important starting point for developing new
anti-melioidosis drugs targeting BpsγCA.
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Xiong X, Li B, Zhou Z, Gu G, Li M, Liu J, Jiao H. The VirB System Plays a Crucial Role in Brucella Intracellular Infection. Int J Mol Sci 2021; 22:ijms222413637. [PMID: 34948430 PMCID: PMC8707931 DOI: 10.3390/ijms222413637] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 12/09/2021] [Accepted: 12/15/2021] [Indexed: 01/18/2023] Open
Abstract
Brucellosis is a highly prevalent zoonotic disease caused by Brucella. Brucella spp. are gram-negative facultative intracellular parasitic bacteria. Its intracellular survival and replication depend on a functional virB system, an operon encoded by VirB1–VirB12. Type IV secretion system (T4SS) encoded by the virB operon is an important virulence factor of Brucella. It can subvert cellular pathway and induce host immune response by secreting effectors, which promotes Brucella replication in host cells and induce persistent infection. Therefore, this paper summarizes the function and significance of the VirB system, focusing on the structure of the VirB system where VirB T4SS mediates biogenesis of the endoplasmic reticulum (ER)-derived replicative Brucella-containing vacuole (rBCV), the effectors of T4SS and the cellular pathways it subverts, which will help better understand the pathogenic mechanism of Brucella and provide new ideas for clinical vaccine research and development.
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Affiliation(s)
- Xue Xiong
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
| | - Bowen Li
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
| | - Zhixiong Zhou
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
| | - Guojing Gu
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
| | - Mengjuan Li
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
| | - Jun Liu
- Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Yujinxiang Street 573, Changchun 130122, China
- Correspondence: (J.L.); (H.J.)
| | - Hanwei Jiao
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
- National Center of Technology Innovation for Pigs, Chongqing 402460, China
- Veterinary Scientific Engineering Research Center, Chongqing 402460, China
- Immunology Research Center, Medical Research Institute, Southwest University, Chongqing 402460, China
- Correspondence: (J.L.); (H.J.)
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Gamma Carbonic Anhydrases from Hydrothermal Vent Bacteria: Cases of Alternating Active Site Due to a Long Loop with Proton Shuttle Residue. Catalysts 2021. [DOI: 10.3390/catal11101177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Accelerated CO2 sequestration uses carbonic anhydrases (CAs) as catalysts; thus, there is much research on these enzymes. The γ-CA from Escherichia coli (EcoCA-γ) was the first γ-CA to display an active site that switches between “open” and “closed” states through Zn2+ coordination by the proton-shuttling His residue. Here, we explored this occurrence in γ-CAs from hydrothermal vent bacteria and also the γ-CA from Methanosarcina thermophila (Cam) using molecular dynamics. Ten sequences were analyzed through multiple sequence alignment and motif analysis, along with three others from a previous study. Conservation of residues and motifs was high, and phylogeny indicated a close relationship amongst the sequences. All structures, like EcoCA-γ, had a long loop harboring the proton-shuttling residue. Trimeric structures were modeled and simulated for 100 ns at 423 K, with all the structures displaying thermostability. A shift between “open” and “closed” active sites was observed in the 10 models simulated through monitoring the behavior of the His proton-shuttling residue. Cam, which has two Glu proton shuttling residues on long loops (Glu62 and Glu84), also showed an active site switch affected by the first Glu proton shuttle, Glu62. This switch was thus concluded to be common amongst γ-CAs and not an isolated occurrence.
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Karan R, Mathew S, Muhammad R, Bautista DB, Vogler M, Eppinger J, Oliva R, Cavallo L, Arold ST, Rueping M. Understanding High-Salt and Cold Adaptation of a Polyextremophilic Enzyme. Microorganisms 2020; 8:microorganisms8101594. [PMID: 33081237 PMCID: PMC7602713 DOI: 10.3390/microorganisms8101594] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 09/30/2020] [Accepted: 10/01/2020] [Indexed: 12/27/2022] Open
Abstract
The haloarchaeon Halorubrum lacusprofundi is among the few polyextremophilic organisms capable of surviving in one of the most extreme aquatic environments on Earth, the Deep Lake of Antarctica (−18 °C to +11.5 °C and 21–28%, w/v salt content). Hence, H. lacusprofundi has been proposed as a model for biotechnology and astrobiology to investigate potential life beyond Earth. To understand the mechanisms that allow proteins to adapt to both salinity and cold, we structurally (including X-ray crystallography and molecular dynamics simulations) and functionally characterized the β-galactosidase from H. lacusprofundi (hla_bga). Recombinant hla_bga (produced in Haloferax volcanii) revealed exceptional stability, tolerating up to 4 M NaCl and up to 20% (v/v) of organic solvents. Despite being cold-adapted, hla_bga was also stable up to 60 °C. Structural analysis showed that hla_bga combined increased surface acidity (associated with halophily) with increased structural flexibility, fine-tuned on a residue level, for sustaining activity at low temperatures. The resulting blend enhanced structural flexibility at low temperatures but also limited protein movements at higher temperatures relative to mesophilic homologs. Collectively, these observations help in understanding the molecular basis of a dual psychrophilic and halophilic adaptation and suggest that such enzymes may be intrinsically stable and functional over an exceptionally large temperature range.
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Affiliation(s)
- Ram Karan
- KAUST Catalysis Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia; (S.M.); (D.B.B.); (M.V.); (J.E.); (R.O.); (L.C.)
- Correspondence: (R.K.); (S.T.A.); (M.R.)
| | - Sam Mathew
- KAUST Catalysis Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia; (S.M.); (D.B.B.); (M.V.); (J.E.); (R.O.); (L.C.)
| | - Reyhan Muhammad
- Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering (BESE), Thuwal 23955-6900, Saudi Arabia;
| | - Didier B. Bautista
- KAUST Catalysis Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia; (S.M.); (D.B.B.); (M.V.); (J.E.); (R.O.); (L.C.)
| | - Malvina Vogler
- KAUST Catalysis Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia; (S.M.); (D.B.B.); (M.V.); (J.E.); (R.O.); (L.C.)
| | - Jorg Eppinger
- KAUST Catalysis Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia; (S.M.); (D.B.B.); (M.V.); (J.E.); (R.O.); (L.C.)
| | - Romina Oliva
- KAUST Catalysis Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia; (S.M.); (D.B.B.); (M.V.); (J.E.); (R.O.); (L.C.)
- Department of Sciences and Technologies, University Parthenope of Naples, Centro Direzionale Isola C4, I-80143 Naples, Italy
| | - Luigi Cavallo
- KAUST Catalysis Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia; (S.M.); (D.B.B.); (M.V.); (J.E.); (R.O.); (L.C.)
| | - Stefan T. Arold
- Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering (BESE), Thuwal 23955-6900, Saudi Arabia;
- Centre de Biochimie Structurale, CNRS, INSERM, Université de Montpellier, 34090 Montpellier, France
- Correspondence: (R.K.); (S.T.A.); (M.R.)
| | - Magnus Rueping
- KAUST Catalysis Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia; (S.M.); (D.B.B.); (M.V.); (J.E.); (R.O.); (L.C.)
- Correspondence: (R.K.); (S.T.A.); (M.R.)
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Vogler M, Karan R, Renn D, Vancea A, Vielberg MT, Grötzinger SW, DasSarma P, DasSarma S, Eppinger J, Groll M, Rueping M. Crystal Structure and Active Site Engineering of a Halophilic γ-Carbonic Anhydrase. Front Microbiol 2020; 11:742. [PMID: 32411108 PMCID: PMC7199487 DOI: 10.3389/fmicb.2020.00742] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 03/30/2020] [Indexed: 11/27/2022] Open
Abstract
Environments previously thought to be uninhabitable offer a tremendous wealth of unexplored microorganisms and enzymes. In this paper, we present the discovery and characterization of a novel γ-carbonic anhydrase (γ-CA) from the polyextreme Red Sea brine pool Discovery Deep (2141 m depth, 44.8°C, 26.2% salt) by single-cell genome sequencing. The extensive analysis of the selected gene helps demonstrate the potential of this culture-independent method. The enzyme was expressed in the bioengineered haloarchaeon Halobacterium sp. NRC-1 and characterized by X-ray crystallography and mutagenesis. The 2.6 Å crystal structure of the protein shows a trimeric arrangement. Within the γ-CA, several possible structural determinants responsible for the enzyme's salt stability could be highlighted. Moreover, the amino acid composition on the protein surface and the intra- and intermolecular interactions within the protein differ significantly from those of its close homologs. To gain further insights into the catalytic residues of the γ-CA enzyme, we created a library of variants around the active site residues and successfully improved the enzyme activity by 17-fold. As several γ-CAs have been reported without measurable activity, this provides further clues as to critical residues. Our study reveals insights into the halophilic γ-CA activity and its unique adaptations. The study of the polyextremophilic carbonic anhydrase provides a basis for outlining insights into strategies for salt adaptation, yielding enzymes with industrially valuable properties, and the underlying mechanisms of protein evolution.
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Affiliation(s)
- Malvina Vogler
- KAUST Catalysis Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Center for Integrated Protein Science Munich, Department of Chemistry, Technische Universität München, Garching, Germany
| | - Ram Karan
- KAUST Catalysis Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Dominik Renn
- KAUST Catalysis Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Alexandra Vancea
- KAUST Catalysis Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Marie-Theres Vielberg
- Center for Integrated Protein Science Munich, Department of Chemistry, Technische Universität München, Garching, Germany
| | - Stefan W. Grötzinger
- KAUST Catalysis Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Priya DasSarma
- Department of Microbiology and Immunology, Institute of Marine and Environmental Technology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Shiladitya DasSarma
- Department of Microbiology and Immunology, Institute of Marine and Environmental Technology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Jörg Eppinger
- KAUST Catalysis Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Michael Groll
- Center for Integrated Protein Science Munich, Department of Chemistry, Technische Universität München, Garching, Germany
| | - Magnus Rueping
- KAUST Catalysis Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
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Wang W, Zhang Y, Wang L, Jing Q, Wang X, Xi X, Zhao X, Wang H. Molecular structure of thermostable and zinc-ion-binding γ-class carbonic anhydrases. Biometals 2019; 32:317-328. [PMID: 30895492 DOI: 10.1007/s10534-019-00190-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 03/18/2019] [Indexed: 12/18/2022]
Abstract
The γ-class carbonic anhydrases (γ-CAs) mainly come from methanogens methane-producing bacteria that grow in hot springs and catalyze the interconversion of carbon dioxide and water to bicarbonate and protons. Here, the γ-CA from Thermus thermophilus HB8 (γ-TtCA) was expressed and purified, its crystal structure was determined at 2.3 Å resolution in space group P1. The asymmetric unit contains two trimers and six catalytic Zn2+. In general, the fold of the protein is similar to those of homologous enzymes from Geobacillus Kaustophilus, Bacillus Cereus, Methanosarcina Thermophila and others. Each monomer comprises a triangular prism-like structure consisting of a left-handed β-helix and a C-terminal α-helix. The catalytic Zn2+ bound to three histidines and a phosphate radical in a tetrahedral fashion. It is located at the interface between the two monomers. Inductively coupled plasma mass spectrometry measurements further suggest that the molar ratio of zinc ions and protein molecules is 1:1. The structure revealed a novel different region situated between the left-handed β-helix and the C-terminal α-helix. Compared to previously reported structures, half of the C-terminal α-helix was replaced with a long loop in this structure. The purified γ-TtCA exhibits no significant carbonic anhydrase activity compared to α-class carbonic anhydrases. This study provides insight into the structural diversity of γ-CAs with potential function for γ-CAs.
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Affiliation(s)
- Wenming Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Education Ministry, Institute of Molecular Science, Shanxi University, Taiyuan, 030006, China.
| | - Yao Zhang
- Key Laboratory of Chemical Biology and Molecular Engineering of Education Ministry, Institute of Molecular Science, Shanxi University, Taiyuan, 030006, China
| | - Lele Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Education Ministry, Institute of Molecular Science, Shanxi University, Taiyuan, 030006, China
| | - Qi Jing
- Key Laboratory of Chemical Biology and Molecular Engineering of Education Ministry, Institute of Molecular Science, Shanxi University, Taiyuan, 030006, China
| | - Xiaolu Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Education Ministry, Institute of Molecular Science, Shanxi University, Taiyuan, 030006, China
| | - Xiaoli Xi
- Key Laboratory of Chemical Biology and Molecular Engineering of Education Ministry, Institute of Molecular Science, Shanxi University, Taiyuan, 030006, China
| | - Xuan Zhao
- Department of Chemistry, University of Memphis, Memphis, TN, 38152, USA
| | - Hongfei Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Education Ministry, Institute of Molecular Science, Shanxi University, Taiyuan, 030006, China.
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Khandavalli LVNS, Lodha T, Abdullah M, Guruprasad L, Chintalapati S, Chintalapati VR. Insights into the carbonic anhydrases and autotrophic carbon dioxide fixation pathways of high CO2 tolerant Rhodovulum viride JA756. Microbiol Res 2018; 215:130-140. [DOI: 10.1016/j.micres.2018.07.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 06/20/2018] [Accepted: 07/13/2018] [Indexed: 10/28/2022]
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Ke Y, Wang Y, Li W, Chen Z. Type IV secretion system of Brucella spp. and its effectors. Front Cell Infect Microbiol 2015; 5:72. [PMID: 26528442 PMCID: PMC4602199 DOI: 10.3389/fcimb.2015.00072] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Accepted: 09/28/2015] [Indexed: 11/13/2022] Open
Abstract
Brucella spp. are intracellular bacterial pathogens that cause infection in domestic and wild animals. They are often used as model organisms to study intracellular bacterial infections. Brucella VirB T4SS is a key virulence factor that plays important roles in mediating intracellular survival and manipulating host immune response to infection. In this review, we discuss the roles of Brucella VirB T4SS and 15 effectors that are proposed to be crucial for Brucella pathogenesis. VirB T4SS regulates the inflammation response and manipulates vesicle trafficking inside host cells. VirB T4SS also plays crucial roles in the inhibition of the host immune response and intracellular survival during infection. Here, we list the key molecular events in the intracellular life cycle of Brucella that are potentially targeted by the VirB T4SS effectors. Elucidating the functions of these effectors will help clarify the molecular role of T4SS during infection. Furthermore, studying the effectors secreted by Brucella spp. might provide insights into the mechanisms used by the bacteria to hijack the host signaling pathways and aid in the development of better vaccines and therapies against brucellosis.
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Affiliation(s)
- Yuehua Ke
- Institute of Disease Control and Prevention, AMMS Beijing, China
| | - Yufei Wang
- Department of Laboratory Medicine, General Hospital of Chinese People's Armed Police Forces Beijing, China
| | - Wengfeng Li
- Department of Orthopedics, The First Affiliated Hospital of General Hospital of People's Liberation Army Beijing, China
| | - Zeliang Chen
- Institute of Disease Control and Prevention, AMMS Beijing, China
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Coordinated zinc homeostasis is essential for the wild-type virulence of Brucella abortus. J Bacteriol 2015; 197:1582-91. [PMID: 25691532 DOI: 10.1128/jb.02543-14] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 02/11/2015] [Indexed: 01/19/2023] Open
Abstract
UNLABELLED Metal homeostasis in bacterial cells is a highly regulated process requiring intricately coordinated import and export, as well as precise sensing of intracellular metal concentrations. The uptake of zinc (Zn) has been linked to the virulence of Brucella abortus; however, the capacity of Brucella strains to sense Zn levels and subsequently coordinate Zn homeostasis has not been described. Here, we show that expression of the genes encoding the zinc uptake system ZnuABC is negatively regulated by the Zn-sensing Fur family transcriptional regulator, Zur, by direct interactions between Zur and the promoter region of znuABC. Moreover, the MerR-type regulator, ZntR, controls the expression of the gene encoding the Zn exporter ZntA by binding directly to its promoter. Deletion of zur or zntR alone did not result in increased zinc toxicity in the corresponding mutants; however, deletion of zntA led to increased sensitivity to Zn but not to other metals, such as Cu and Ni, suggesting that ZntA is a Zn-specific exporter. Strikingly, deletion of zntR resulted in significant attenuation of B. abortus in a mouse model of chronic infection, and subsequent experiments revealed that overexpression of zntA in the zntR mutant is the molecular basis for its decreased virulence. IMPORTANCE The importance of zinc uptake for Brucella pathogenesis has been demonstrated previously, but to date, there has been no description of how overall zinc homeostasis is maintained and genetically controlled in the brucellae. The present work defines the predominant zinc export system, as well as the key genetic regulators of both zinc uptake and export in Brucella abortus. Moreover, the data show the importance of precise coordination of the zinc homeostasis systems as disregulation of some elements of these systems leads to the attenuation of Brucella virulence in a mouse model. Overall, this study advances our understanding of the essential role of zinc in the pathogenesis of intracellular bacteria.
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