The potassium binding protein Kbp is a cytoplasmic potassium sensor

Ashraf, K. U., Josts, I., Mosbahi, K., Kelly, S. M. , Byron, O., Smith, B. O. and Walker, D. (2016) The potassium binding protein Kbp is a cytoplasmic potassium sensor. Structure, 24(5), pp. 741-749. (doi:10.1016/j.str.2016.03.017) (PMID:27112601)

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Abstract

Escherichia coli possesses a number of specific K+ influx and efflux systems that maintain an appropriate intracellular K+ concentration. Although regulatory mechanisms have been identified for a number of these transport systems, the exact mechanism through which K+ concentration is sensed in the cell remains unknown. In this work we show that Kbp (K+ binding protein, formerly YgaU), a soluble 16-kDa cytoplasmic protein from Escherichia coli, is a highly specific K+ binding protein and is required for normal growth in the presence of high levels of external K+. Kbp binds a single potassium ion with high specificity over Na+ and other metal ions found in biological systems, although, in common with K+ transporters, it also binds Rb+ and Cs+. Dissection of the K+ binding determinants of Kbp suggests a mechanism through which Kbp is able to sense changes in K+ concentration over the relevant range of intracellular K+ concentrations.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Walker, Professor Daniel and Smith, Dr Brian and Byron, Professor Olwyn and Ashraf, Mr Khuram and Mosbahi, Dr Khedidja and Kelly, Dr Sharon
Authors: Ashraf, K. U., Josts, I., Mosbahi, K., Kelly, S. M., Byron, O., Smith, B. O., and Walker, D.
College/School:College of Medical Veterinary and Life Sciences > Institute of Infection Immunity and Inflammation
College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
College of Medical Veterinary and Life Sciences > School of Life Sciences
Journal Name:Structure
Publisher:Elsevier (Cell Press)
ISSN:0969-2126
ISSN (Online):1878-4186
Published Online:21 April 2016
Copyright Holders:Copyright © 2016 Elsevier Ltd
First Published:First published in Structure 24(5):741-749
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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