Characterization of a new feedback-resistant 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase AroF of Escherichia coli

Jossek, G. M. D.; Bongaerts, J.; Sprenger, G. A.

doi:10.1111/j.1574-6968.2001.tb10795.x

Journal Article

Characterization of a new feedback-resistant 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase AroF of Escherichia coli

Jossek, G. M. D.FZJ* ; Bongaerts, J. ; Sprenger, G. A.FZJ*

2001
Wiley-Blackwell Oxford [u.a.]

FEMS microbiology letters 202, 145 - 148 (2001) [10.1111/j.1574-6968.2001.tb10795.x]

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Please use a persistent id in citations: http://hdl.handle.net/2128/28466 doi:10.1111/j.1574-6968.2001.tb10795.x

Abstract: Tyrosine feedback-inhibits the 3-deoxy-d-arabino-heptulosonate 7-phosphate (DAHP) synthase isoenzyme AroF of Escherichia coli. Here we show that an Asn-8 to Lys-8 substitution in AroF leads to a tyrosine-insensitive DAHP synthase. This mutant enzyme exhibited similar activities (v=30–40 U mg−1) and substrate affinities (Kmerythrose-4-phosphate=0.5 mM, positive cooperativity with respect to phospho(enol)pyruvate) as the wild-type AroF, but showed decreased thermostability. An engineered AroF enzyme lacking the seven N-terminal residues also was tyrosine-resistant. These results strongly suggest that the N-terminus of AroF is involved in the molecular interactions occurring in the feedback-inhibition mechanism.

Keyword(s): 3-deoxy-D-arabino-heptulosonate synthase (auto) ; feedback-inhibition (auto) ; AroF (auto) ; tyrosine resistance (auto) ; Escherichia coli (auto)