The hydrogen bonding network of coproheme in coproheme decarboxylase from Listeria monocytogenes: Effect on structure and catalysis.

The hydrogen bonding network of coproheme in coproheme decarboxylase from Listeria monocytogenes: Effect on structure and catalysis. J Inorg Biochem. 2019 Mar 21;195:61-70 Authors: Milazzo L, Gabler T, Pfanzagl V, Michlits H, Furtmüller PG, Obinger C, Hofbauer S, Smulevich G Abstract Coproheme decarboxylase (ChdC) catalyzes the oxidative decarboxylation of coproheme to heme b, i.e. the last step in the recently described coproporphyrin-dependent pathway. Coproheme decarboxylation from Listeria monocytogenes is a robust enzymatic reaction of low catalytic efficiency. Coproheme acts as both substrate and redox cofactor activated by H2O2. It fully depends on the catalytic Y147 close to the propionyl group at position 2. In the present study we have investigated the effect of disruption of the comprehensive and conserved hydrogen bonding network between the four propionates and heme cavity residues on (i) the conformational stability of the heme cavity, (ii) the electronic configuration of the ferric redox cofactor/substrate, (iii) the binding of carbon monoxide and, (iv) the decarboxylation reaction mediated by addition of H2O2. Nine single, double and triple mutants of ChdC from Listeria monocytogenes were produced in E. coli. The respective coproheme- and heme b-complexed proteins were studied by UV-Vis, resonance Raman, circular dichroism spectroscopy, and mass spectrometry. Interactions of propionates 2 and 4 with residues in the h...
Source: Journal of Inorganic Biochemistry - Category: Biochemistry Authors: Tags: J Inorg Biochem Source Type: research