Biosynthetic substitution of tyrosine in green fluorescent protein with its surrogate fluorotyrosine in Escherichia coli.

ABSTRACT

Introduction of a fluorine moiety into green fluorescent protein offers an interesting novel spectral variant. The calculated binding energy of fluorotyrosine (F-Tyr) (-8.42 kcal/mol) for tyrosyl tRNA synthetase was moderately higher than that of tyrosine (Tyr) (-8.36 kcal/mol). This result directly correlated with the expression level of F-Tyr containing GFP (38 mg/l), which was comparably higher than that of the parent GFP expression level (34 mg/l). Finally, we generated a model structure for GFP to assess possible interaction in the chromophore of the protein structure, which plays an important role in determining the spectral and folding behaviors of the F-Tyr incorporated GFP variant.