A More Stable Leucine Zipper

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Science  04 May 2001:
Vol. 292, Issue 5518, pp. 811
DOI: 10.1126/science.292.5518.811a

Incorporation of unnatural amino acids into peptides and proteins modifies their properties in unique ways. New functionalities that do not exist in peptides containing only natural amino acids can be introduced, which may be important in applications from drug design to enzyme catalysis. Tang et al. have incorporated a “hyperhydrophobic” modification of leucine, trifluoroleucine, into leucine zipper peptides in bacterial cultures. The extent of leucine replacement was 92% when the bacteria were grown in medium containing only the trifluorinated leucine. The resulting leucine zippers were more stable to denaturation than those of the wild-type protein, while the overall structural characteristics remained the same. In contrast, substitution of leucine by other natural amino acids results in reduced structural stability. In the future, the in vivo incorporation of trifluoroleucine and similar hyperhydrophobic residues may be useful for stabilizing a variety of other hydrophobic protein cores. — JU

Angew. Chem. Int. Ed.40, 1494 (2001).

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