Enzyme Substrate Complex of the H200C Variant of Homoprotocatechuate 2,3-Dioxygenase: Mossbauer and Computational Studies.

ABSTRACT: The extradiol, aromatic ring-cleaving enzyme homoprotocatechuate 2,3-dioxygenase (HPCD) catalyzes a complex chain of reactions that involve second sphere residues of the active site. The importance of the second-sphere residue His200 was demonstrated in studies of HPCD variants, such as His200Cys (H200C), which revealed significant retardations of certain steps in the catalytic process as a result of the substitution, allowing novel reaction cycle intermediates to be trapped for spectroscopic characterization. As the H200C variant largely retains the wild-type active site structure and produces the correct ring-cleaved product, this variant presents a valuable target for mechanistic HPCD studies. Here, the high-spin Fe(II) states of resting H200C and the H200C-homoprotocatechuate enzyme-su

SUBMITTER: Meier KK 

PROVIDER: S-EPMC4924929 | biostudies-literature | 2016 Jun

REPOSITORIES: biostudies-literature