Toggle Main Menu Toggle Search

Open Access padlockePrints

Large-scale millisecond intersubunit dynamics in the B subunit homopentamer of the toxin derived from Escherichia coli O157

Lookup NU author(s): Professor Steve Homans


Full text for this publication is not currently held within this repository. Alternative links are provided below where available.


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, ΔH1° = −116.3 ± 0.55 kJ/mol, and ΔH2° = −50.3 ± 0.11 kJ/mol) indicate favorable entropic cooperativity that has not previously been observed in multivalent systems.

Publication metadata

Author(s): Yung A, Turnbull WB, Kalverda AP, Thompson GS, Homans SW, Kitov P, Bundle DR

Publication type: Article

Publication status: Published

Journal: Journal of the American Chemical Society

Year: 2003

Volume: 125

Issue: 43

Pages: 13058-13062

ISSN (print): 0002-7863

ISSN (electronic): 1943-2984

Publisher: American Chemical Society


DOI: 10.1021/ja0367288


Altmetrics provided by Altmetric