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Publication Abstract from PubMed

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.

The Potassium Binding Protein Kbp Is a Cytoplasmic Potassium Sensor.,Ashraf KU, Josts I, Mosbahi K, Kelly SM, Byron O, Smith BO, Walker D Structure. 2016 May 3;24(5):741-9. doi: 10.1016/j.str.2016.03.017. Epub 2016 Apr , 21. PMID:27112601^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.