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Verma P, Chattopadhyay K. Current Perspective on the Membrane-Damaging Action of Thermostable Direct Hemolysin, an Atypical Bacterial Pore-forming Toxin. Front Mol Biosci 2021; 8:717147. [PMID: 34368235 PMCID: PMC8343067 DOI: 10.3389/fmolb.2021.717147] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 07/12/2021] [Indexed: 11/13/2022] Open
Abstract
Thermostable direct hemolysin (TDH) is the major virulence determinant of the gastroenteric bacterial pathogen Vibrio parahaemolyticus. TDH is a membrane-damaging pore-forming toxin (PFT). TDH shares remarkable structural similarity with the actinoporin family of eukaryotic PFTs produced by the sea anemones. Unlike most of the PFTs, it exists as tetramer in solution, and such assembly state is crucial for its functionality. Although the structure of the tetrameric assembly of TDH in solution is known, membrane pore structure is not available yet. Also, the specific membrane-interaction mechanisms of TDH, and the exact role of any receptor(s) in such process, still remain unclear. In this mini review, we discuss some of the unique structural and physicochemical properties of TDH, and their implications for the membrane-damaging action of the toxin. We also present our current understanding regarding the membrane pore-formation mechanism of this atypical bacterial PFT.
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Affiliation(s)
- Pratima Verma
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, India
| | - Kausik Chattopadhyay
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, India
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Wang YK, Huang SC, Chang CY, Huang WT, Liao MJ, Yip BS, Chou FP, Li TTH, Wu TK. Multiple Pleomorphic Tetramers of Thermostable Direct Hemolysin from Grimontia hollisae in Exerting Hemolysis and Membrane Binding. Sci Rep 2019; 9:9833. [PMID: 31285470 PMCID: PMC6614540 DOI: 10.1038/s41598-019-46354-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 06/18/2019] [Indexed: 11/20/2022] Open
Abstract
Oligomerization of protein into specific quaternary structures plays important biological functions, including regulation of gene expression, enzymes activity, and cell-cell interactions. Here, we report the determination of two crystal structures of the Grimontia hollisae (formally described as Vibrio hollisae) thermostable direct hemolysin (Gh-TDH), a pore-forming toxin. The toxin crystalized in the same space group of P21212, but with two different crystal packing patterns, each revealing three consistent tetrameric oligomerization forms called Oligomer-I, -II, and -III. A central pore with comparable depth of ~50 Å but differing in shape and size was observed in all determined toxin tetrameric oligomers. A common motif of a toxin dimer was found in all determined structures, suggesting a plausible minimum functional unit within the tetrameric structure in cell membrane binding and possible hemolytic activity. Our results show that bacterial toxins may form a single or highly symmetric oligomerization state when exerting their biological functions. The dynamic nature of multiple symmetric oligomers formed upon release of the toxin may open a niche for bacteria survival in harsh living environments.
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Affiliation(s)
- Yu-Kuo Wang
- Department of Biological Science and Technology, National Chiao Tung University, Hsin-Chu, 30010, Taiwan, Republic of China
| | - Sheng-Cih Huang
- Department of Biological Science and Technology, National Chiao Tung University, Hsin-Chu, 30010, Taiwan, Republic of China
| | - Chin-Yuan Chang
- Department of Biological Science and Technology, National Chiao Tung University, Hsin-Chu, 30010, Taiwan, Republic of China
| | - Wan-Ting Huang
- Department of Biological Science and Technology, National Chiao Tung University, Hsin-Chu, 30010, Taiwan, Republic of China
| | - Man-Jun Liao
- Department of Biological Science and Technology, National Chiao Tung University, Hsin-Chu, 30010, Taiwan, Republic of China
| | - Bak-Sau Yip
- Department of Neurology, National Taiwan University Hospital, Hsin-Chu, 30059, Taiwan, Republic of China
| | - Feng-Pai Chou
- Department of Biological Science and Technology, National Chiao Tung University, Hsin-Chu, 30010, Taiwan, Republic of China
| | - Thomas Tien-Hsiung Li
- Graduate Institute of Biochemistry, National Chung Hsing University, Taichung, 40227, Taiwan, Republic of China.
| | - Tung-Kung Wu
- Department of Biological Science and Technology, National Chiao Tung University, Hsin-Chu, 30010, Taiwan, Republic of China.
- Center for Emergent Functional Matter Science, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu, 30010, Taiwan, Republic of China.
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Hamada D, Higurashi T, Mayanagi K, Miyata T, Fukui T, Iida T, Honda T, Yanagihara I. Tetrameric Structure of Thermostable Direct Hemolysin from Vibrio parahaemolyticus Revealed by Ultracentrifugation, Small-angle X-ray Scattering and Electron Microscopy. J Mol Biol 2007; 365:187-95. [PMID: 17056060 DOI: 10.1016/j.jmb.2006.09.070] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2006] [Revised: 09/14/2006] [Accepted: 09/26/2006] [Indexed: 10/24/2022]
Abstract
The thermostable direct hemolysin (TDH) is a major virulence factor of Vibrio parahaemolyticus. We have characterized the conformational properties of TDH by small-angle X-ray scattering (SAXS), ultracentrifugation and transmission electron microscopy. Sedimentation equilibrium and velocity studies revealed that the protein is tetrameric in aqueous solvents. The Guinier plot derived from SAXS data provided a radius of gyration of 29.0 A. The elongated pattern with a shoulder of a pair distance distribution function derived from SAXS data suggested the presence of molecules with an anisotropic shape having a maximum diameter of 98 A. Electron microscopic image analysis of the negatively stained TDH oligomer showed the presence of C(4) symmetric particles with edge and diagonal lengths of 65 A and 80 A, respectively. Shape reconstruction was carried out by ab initio calculations using the SAXS data with a C(4) symmetric approximation. These results suggested that the tetrameric TDH assumes an oblate structure. The hydrodynamic parameters predicted from the ab initio model differed slightly from the experimental values, suggesting the presence of flexible segments.
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Affiliation(s)
- Daizo Hamada
- Department of Developmental Infectious Diseases, Research Institute, Osaka Medical Center for Maternal and Child Health, 840 Murodo, Izumi, Osaka 594-1011, Japan
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