Description of a Versatile Peroxidase Involved in the Natural Degradation of Lignin That Has Both Manganese Peroxidase and Lignin Peroxidase Substrate Interaction Sites

作者：Susana Camarero, Sovan Sarkar, Francisco Javier Ruiz-Dueñas, Marı́a Jesús Martı́nez, Ángel T. Martı́nez, Ángel T. Martı́nez · 发表于：Journal of Biological Chemistry · 年份：1999 · DOI：10.1074/jbc.274.15.10324 · 被引用次数：396 · 研究领域：Enzyme-mediated dye degradation、Analytical chemistry methods development、Chromium effects and bioremediation

Two major peroxidases are secreted by the fungus Pleurotus eryngii in lignocellulose cultures. One is similar to Phanerochaete chrysosporium manganese-dependent peroxidase. The second protein (PS1), although catalyzing the oxidation of Mn2+ to Mn3+ by H2O2, differs from the above enzymes by its manganese-independent activity enabling it to oxidize substituted phenols and synthetic dyes, as well as the lignin peroxidase (LiP) substrate veratryl alcohol. This is by a mechanism similar to that reported for LiP, as evidenced by p-dimethoxybenzene oxidation yielding benzoquinone. The apparent kinetic constants showed high activity on Mn2+, but methoxyhydroquinone was the natural substrate with the highest enzyme affinity (this and other phenolic substrates are not efficiently oxidized by the P. chrysosporium peroxidases). A three-dimensional model was built using crystal models from four fungal peroxidase as templates. The model suggests high structural affinity of this versatile peroxidase with LiP but shows a putative Mn2+ binding site near the internal heme propionate, involving Glu36, Glu40, and Asp181. A specific substrate interaction site for Mn2+ is supported by kinetic data showing noncompetitive inhibition with other peroxidase substrates. Moreover, residues reported as involved in LiP interaction with veratryl alcohol and other aromatic substrates are present in peroxidase PS1 such as His82 at the heme-channel opening, which is remarkably similar to that of P. chrysospor...