User:Victoria Mock/Sandbox 1

From Proteopedia

Green Fluorescent Protein (GFP) is a valuable tool in cellular and molecular biology, largely because of the self-fluorescing properties of its chromophore. This fluorescence permits the molecule to function as a protein fusion tag in bacterial cells. Wild-type GFP and many of its mutant variants tend to misfold when used as protein fusion tags, often due to poor folding of the bacterial proteins themselves, which then hinders GFP from assuming its proper conformation and causes it to aggregate and display weaker fluorescence. Consequently, a “robustly folded” GFP variant, called superfolder GFP, was developed to withstand any folding complications of the protein it was designed to tag.

The amino acid mutations that give superfolder GFP its durability are located within the protein's beta-can structure, away from the central chromophore. Wild-type GFP possesses a serine residue on beta strand S2 at position 30, which is mutated to arginine in superfolder GFP, changing the local conformation and interactions with four key surrounding residues. Altogether, a five-membered ion-pair network is created by glu-32, arg-30, glu-17, arg-122, and glu-115.