The Effect of pH on Green Fluorescent Protein : a Brief Review

Green fluorescent protein (GFP) is rapidly becoming one of the most frequently employed molecular reporters. Its use in monitoring gene expression and protein localization has been well documented. Different mutational approaches have created numerous GFP variants with optimized expression, differing spectra, and differing pH sensitivity. This last characteristic, though still poorly understood mechanistically, has attracted an increasing amount of interest. To date, GFP variants have been developed with pKas ranging from 4.8 (T203I) to 8.0 (YFP-H148G/ T203Y). The objective of this review is to outline both the effect of pH on GFP fluorescence and the uses of GFP to study processes in different pH environments.