1.11.1.5 evolution MacA belongs to the family of diheme cytochrome c peroxidases -, 724337 1.11.1.5 malfunction an enzyme knockout mutant DELTAZmcytC exhibits filamentous shapes and reduction in growth under a shaking condition at a high temperature compared to the parental strain and became hypersensitive to exogenous H2O2. Under the same condition, the mutation causes increased expression of genes for three other antioxidant enzymes. Peroxidase activity almost abolished in mutant DELTA ZmcytC. The enzyme knockout mutant strain shows activity with ubiquinol-1 as a substrate but not with reduced horse heart cytochrome c, and it shows antimycin A-sensitive NADH oxidase activity 725756 1.11.1.5 malfunction significantly higher H2O2 accumulation in ccp1-null cells and catalytically inactive Ccp1W191F mutant cells. Ccp1W191F is a more persistent H2O2 signaling protein than wild-type Ccp1 -, 725070 1.11.1.5 malfunction while the wild-type CcP is very stable to oxidative degradation by excess hydrogen peroxide, CcP mutant R48A/W51A/H52A is inactivated within four cycles of the peroxygenase reaction 724658 1.11.1.5 metabolism bacterial diheme c-type cytochrome peroxidases catalyze the periplasmic reduction of hydrogen peroxide to water. CcpA does not seem to be part of a CymAMtrA-FccA-based electron transfer network in the periplasm of Shewanella oneidensis 724008 1.11.1.5 additional information CcP requires reductive activation for full activity. The rates of catalysis and activation differ between maltose-binding-protein-fusion and tag-free CcP and also depend on the identity of the electron donor 724366 1.11.1.5 additional information cytochrome c peroxidase-cytochrome c complex: the binding interface between LmP and LmCytc has one strong and one weak ionic interaction, the Lm redox pair is more dependent on ionic interactions than on nonpolar interactions 726385 1.11.1.5 additional information enzyme-cytochrome c protein-protein docking and modeling, overview 724335 1.11.1.5 additional information His175 and Asp235 in the proximal heme pocket form another H-bonding cluster that provides a proton-binding site that is responsive to changes in the redox state of the heme iron. Arg-48 is not a good candidate for the proton-binding site. Arg48 interacts with multiple waters, is located near the bottom of the solvent-access channel in CcP. The carboxylate group of heme propionate-7, His181, and Asp37 form a hydrogen-bonded cluster near the heme iron -, 725645 1.11.1.5 additional information resting ferric (FeIII) Ccp1III is oxidized by H2O2 to compound I,which has a FeIV heme and a cation radical on residue W191. Compound I reacts with ferrous (FeII) Cyc1II to form compound II with a FeIV heme but no W191 radical. Reaction with a second Cyc1II reduces the FeIV heme to yield resting Ccp1III. The Ccp1W191F variant rapidly reacts with H2O2 but is very slowly reduced by Cyc1II such that it exhibits negligible Cyc1II-oxidizing activity, reaction mechanism, overview -, 725070