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N-Terminal Region of Vibrio parahemolyticus Thermostable Direct Hemolysin Regulates the Membrane-Damaging Action of the Toxin

Kundu, N and Verma, P and Kumar, A and Dhar, V and Dutta, S and Chattopadhyay, K (2020) N-Terminal Region of Vibrio parahemolyticus Thermostable Direct Hemolysin Regulates the Membrane-Damaging Action of the Toxin. In: Biochemistry, 59 (4). pp. 605-614.

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Official URL: https://doi.org/10.1021/acs.biochem.9b00937


Thermostable direct hemolysin (TDH) of Vibrio parahemolyticus is a membrane-damaging pore-forming toxin with potent cytolytic/cytotoxic activity. TDH exists as a tetramer consisting of protomers with a core β-sandwich domain, flanked by an 11-amino acid long N-terminal region (NTR). This NTR could not be modeled in the previously determined crystal structure of TDH. Moreover, the functional implication of NTR for the membrane-damaging action of TDH remains unknown. In the present study, we have explored the implications of NTR for the structure-function mechanism of TDH. Our data show that the presence of NTR modulates the physicochemical property of TDH in terms of augmenting the amyloidogenic propensity of the protein. Deletion of NTR compromises the binding of TDH toward target cell membranes and drastically affects the membrane-damaging cytolytic/cytotoxic activity of the toxin. Mutations of aromatic/hydrophobic residues within NTR also confer compromised cell-killing activity. Moreover, covalent trapping of NTR, via an engineered disulfide bond, against the core β-sandwich domain also abrogates the cytolytic/cytotoxic activity of TDH. This observation suggests that an unrestrained configuration of NTR is crucial for the membrane-damaging action of TDH. On the basis of our study, we propose a model explaining the role of NTR in the membrane-damaging function of TDH

Item Type: Journal Article
Publication: Biochemistry
Publisher: American Chemical Society
Additional Information: The copyright for this article belongs to the American Chemical Society
Keywords: Blood; Covalent bonds; Crystal structure; Cytology; Physicochemical properties; Sulfur compounds; Toxic materials, Cell killing; Disulfide bonds; N-terminals; Pore forming toxins; Protomers; Structure functions; Tetramers; Thermostable direct, Membranes, amyloid protein; aromatic amino acid; hemolysin; thermostable direct hemolysin; unclassified drug; bacterial protein; bacterial toxin; hemolysin; hemolysin, Vibrio; thermostable direct hemolysin; thermostable direct hemolysin-related hemolysin protein, Vibrio parahaemolyticus, amino terminal sequence; Article; beta chain; cell killing; cell membrane; controlled study; covalent bond; cytolysis; disulfide bond; human; human cell; hydrophobicity; membrane damage; mutation; nonhuman; physical chemistry; priority journal; protein binding; protein domain; protein function; protein structure; regulatory mechanism; structure activity relation; Vibrio parahaemolyticus; biochemistry; chemistry; genetics; hemolysis; metabolism; physiology; protein subunit; transport at the cellular level; ultrastructure; Vibrio parahaemolyticus, Bacterial Proteins; Bacterial Toxins; Biochemical Phenomena; Biological Transport; Hemolysin Proteins; Hemolysis; Humans; Mutation; Protein Subunits; Vibrio parahaemolyticus
Department/Centre: Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited: 02 Feb 2023 07:11
Last Modified: 02 Feb 2023 07:11
URI: https://eprints.iisc.ac.in/id/eprint/79734

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