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Publication Abstract from PubMed

Potassium ion (K(+)) is the most abundant metal ion in cells and plays an indispensable role in practically all biological systems. Although there have been reports of both synthetic and genetically encoded fluorescent K(+) indicators, there remains a need for an indicator that is genetically targetable, has high specificity for K(+) versus Na(+), and has a high fluorescent response in the red to far-red wavelength range. Here, we introduce a series of chemigenetic K(+) indicators, designated as the HaloKbp1 series, based on the bacterial K(+)-binding protein (Kbp) inserted into HaloTag7 self-labeled with environmentally sensitive rhodamine derivatives. This series of high-performance indicators features high brightness in the red to far-red region, large intensiometric fluorescence changes, and a range of K(d) values. We demonstrate that they are suitable for the detection of physiologically relevant K(+) concentration changes such as those that result from the Ca(2+)-dependent activation of the BK potassium channel.

High-Performance Chemigenetic Potassium Ion Indicator.,Cheng D, Ouyang Z, He X, Nasu Y, Wen Y, Terai T, Campbell RE J Am Chem Soc. 2024 Nov 27. doi: 10.1021/jacs.4c10917. PMID:39601449^[1]

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