Identification of mNeonGreen as a pH-Dependent, Turn-On Fluorescent Protein Sensor for Chloride.

ABSTRACT: Chloride-sensitive fluorescent proteins generated from laboratory evolution have a characteristic tyrosine residue that interacts with a chloride ion and π-stacks with the chromophore. However, the engineered yellow-green fluorescent protein mNeonGreen lacks this interaction but still binds chloride, as seen in a recently reported crystal structure. Based on its unique coordination sphere, we were curious if chloride could influence the optical properties of mNeonGreen. Here, we present the structure-guided identification and spectroscopic characterization of mNeonGreen as a turn-on fluorescent protein sensor for chloride. Our results show that chloride binding lowers the chromophore pK_a and shifts the equilibrium away from the weakly fluorescent phenol form to the highly fluore

SUBMITTER: Tutol JN 

PROVIDER: S-EPMC6663633 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature