Fluorinated Coiled-Coil Proteins Prepared In Vivo Display Enhanced Thermal and Chemical Stability

Fluorination of the hydrophobic core of a coiled-coil protein significantly improved its stability toward thermal and chemical denaturation. 5',5',5'-Trifluoroleucine (2) was efficiently incorporated into a leucine-zipper protein in place of leucine (1) during E. coli biosynthesis. The fluorinated variant maintained stable secondary and tertiary structures under conditions that caused denaturation of the "wild-type" protein.