Large-Scale Millisecond Intersubunit Dynamics in the B Subunit Homopentamer of the Toxin Derived from Escherichia coli O157

Yung, A and Turnbull, WB and Kalverda, AP and Thompson, GS and Homans, SW and Kitov, PI and Bundle, DR (2003) Large-Scale Millisecond Intersubunit Dynamics in the B Subunit Homopentamer of the Toxin Derived from Escherichia coli O157. Journal of the American Chemical Society, 125 . pp. 13058-13062. ISSN 0002-7863. (doi:https://doi.org/10.1021/ja0367288) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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Official URL
http://dx.doi.org/10.1021/ja0367288

Abstract

We report here solution NMR relaxation measurements that show millisecond time-scale intersubunit dynamics in the homopentameric B subunit (VTB) of the toxin derived from Escherichia coli O157. These data are consistent with interconversion between an axially symmetric form and a low-abundance (?10%, 45 °C) higher energy form. The higher energy state is depopulated on binding of a novel bivalent analogue (Pk dimer) of the natural carbohydrate acceptor globotriaosylceramide. The isothermal titration calorimetry isotherm for the binding of Pk dimer to VTB is consistent with a five-site sequential binding model which assumes that cooperative effects arise through communication only between neighboring binding sites. The resulting thermodynamic parameters (Ka1 = 114 ± 2.2 M-1, Ka2 = 283 ± 4.5 M-1, ?H1° = ?116.3 ± 0.55 kJ/mol, and ?H2° = ?50.3 ± 0.11 kJ/mol) indicate favorable entropic cooperativity that has not previously been observed in multivalent systems.

Item Type: Article
Subjects: Q Science > QP Physiology (Living systems) > QP517 Biochemistry
Divisions: Faculties > Sciences > School of Biosciences
Depositing User: G. Thompson
Date Deposited: 23 Jan 2019 17:48 UTC
Last Modified: 23 Jan 2019 17:48 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/71820 (The current URI for this page, for reference purposes)
Thompson, GS: https://orcid.org/0000-0001-9399-7636
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