Manganese Peroxidase from Phanerochaete chrysosporium

Abstract

A detailed three-dimensional model of manganese peroxidase was constructed using lignine peroxidase as the structural scaffold. This is the only protein in the peroxidase family except for cytochrome c peroxidase for which a resolved crystal structure is available.The model was built using the following procedure: (a) structurally preserved regions were derived from similar regions in the sequence alignment of the two proteins; (b) non-similar regions were modelled by searching a set of resolved protein structures for fragments which fitted in geometrically and choosing the best fitting fragment. Side chains were constructed by calculating rotamer-rotamer interaction energies and minimizing intramolecular energy. Model refinement was performed by molecular mechanics calculation.The quality of the model was assessed on the basis of the propensity of the amino acids to be inserted into regular secondary-structure elements and to be exposed to solvent.All the lignine peroxidase regions not used for model construction because of the lack of similarity, except the helix fragment Leu261 -Phe269, correspond to external loops, suggesting reliable modelling.The manganese peroxidase model structure was analyzed in detail and several functionally relevant structural features were predicted, the most important being : (a) the very close structural similarity between lignine and manganese peroxidase active sites, suggesting a similar mode of hydrogen peroxide activation; (b) the substitution of polar residues for the hydrophobic amino acids exposed at the edge of the channel involved in substrate recognition in lignine peroxidase, suggesting that manganese peroxidase does not directly bind aromatic substrates; (c) the location of residues potentially able to bind Mn2+, spatially positioned on the side of the 3-CH3 heme edge.

Biomass pyrolysis liquid to citric acid via 2-step bioconversion

“…The pyrolysis liquid can be used as carbon source for P. chrysosporium EBL0511 to grow at higher concentration, possibly because of higher concentration of hydrogen ion. The system of ligninolytic enzyme from P. chrysosporium is composed of lignin peroxidase, manganese peroxidase and glyoxal oxidase, which has a special degrading mechanism [ 25 ]. Similar to the oxidation of malonate by Manganese peroxidase (MnP) [ 26 ], for example, its biochemical reactions involved in the oxidation of glycolaldehyde by MnP are proposed as following 0ons ( 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 and 9 ): …”