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Conversion of hydroxyphenylpyruvate dioxygenases into hydroxymandelate synthases by directed evolution
Author(s) -
O’Hare Helen M.,
Huang Fanglu,
Holding Andrew,
Choroba Oliver W.,
Spencer Jonathan B.
Publication year - 2006
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2006.05.018
Subject(s) - dioxygenase , active site , biochemistry , heme , chemistry , catabolism , steric effects , tyrosine , yield (engineering) , enzyme , biology , stereochemistry , materials science , metallurgy
Hydroxymandelate synthase (HmaS) and hydroxyphenylpyruvate dioxygenase (HppD) are non‐heme iron‐dependent dioxygenases, which share a common substrate and first catalytic step. The catalytic pathways then diverge to yield hydroxymandelate for secondary metabolism, or homogentisate in tyrosine catabolism. To probe the differences between these related active sites that channel a common intermediate down alternative pathways, we attempted to interconvert their activities by directed evolution. HmaS activity was readily introduced to HppD by just two amino acid changes. A parallel attempt to engineer HppD activity in HmaS was unsuccessful, suggesting that homogentisate synthesis places greater chemical and steric demands on the active site.