Comparison of monomeric variants of StayGold

Abstract

AbstractStayGold is a bright and highly photostable fluorescent protein (FP) that forms an obligate dimer, thereby limiting its application as a soluble marker. On the basis of the structural information of this FP, we disrupted the dimerization to generate a monomeric variant, mStayGold, which inherits both the extremely high photostability and the high practical brightness of StayGold, for molecular fusion and membrane-targeting applications. Meanwhile, two other research groups have independently monomerized StayGold using different strategies. As a result, multiple StayGold monomers are currently available, creating confusion in the research community. In the present study, we investigated the three basic properties—photostability, brightness, and dispersibility—of these monomers by performing detailed side-by-side comparisons. This study highlights the difficulties of StayGold monomerization with emphasis on the tradeoff between photostability and brightness in FP technology.