Site-directed mutagenesis switching a dimethylallyl tryptophan synthase to a specific tyrosine C3-prenylating enzyme


The tryptophan prenyltransferases FgaPT2 and 7-DMATS (7-dimethylallyl tryptophan synthase) from Aspergillus fumigatus catalyze C(4)- and C(7)-prenylation of the indole ring, respectively. 7-DMATS was found to accept l-tyrosine as substrate as well and converted it to an O-prenylated derivative. An acceptance of l-tyrosine by FgaPT2 was also observed in this study. Interestingly, isolation and structure elucidation revealed the identification of a C(3)-prenylated l-tyrosine as enzyme product. Molecular modeling and site-directed mutagenesis led to creation of a mutant FgaPT2_K174F, which showed much higher specificity toward l-tyrosine than l-tryptophan. Its catalytic efficiency toward l-tyrosine was found to be 4.9-fold in comparison with that of non-mutated FgaPT2, whereas the activity toward l-tryptophan was less than 0.4% of that of the wild-type. To the best of our knowledge, this is the first report on an enzymatic C-prenylation of l-tyrosine as free amino acid and altering the substrate preference of a prenyltransferase by mutagenesis.


Aili Fan, Georg Zocher, Edyta Stec, Thilo Stehle, Shu-Ming Li


Journal of Biological Chemistry

Year, Volume, Page

2015, 290, 1364



Tag Element Regiochemistry Product Substrate Cofactor Enzyme
PTDBREC00165 C Regular FgaPT2
PTDBREC00166 C Regular FgaPT2
PTDBREC00167 C Regular FgaPT2_K174F
PTDBREC00168 C Regular FgaPT2
PTDBREC00169 C Regular FgaPT2_K174F
PTDBREC00170 N Regular FgaPT2
PTDBREC00171 N Regular FgaPT2_K174F