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)

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 Ashraf, Mr Khuram and Mosbahi, Dr Khedidja and Kelly, Dr Sharon and Smith, Dr Brian and Byron, Professor Olwyn
• 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 > School of Infection & Immunity; College of Medical Veterinary and Life Sciences > School of Molecular Biosciences; 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