Acid-Tolerant Monomeric GFP from Olindias formosa (Cell Chemical Biology)

Shinoda et al. describe the cloning, engineering, and characterization of a monomeric GFP `Gamillus` from Olindias formosa. Gamillus has superior acid tolerance (pKa = 3.4) to reported other monomeric GFPs, and a unique trans chromophore configuration contributed to the acid tolerance. They demonstrate the usefulness for imaging in an acidic cellular environment, e.g., lysosomes.