Mechanism for Oxidation of High-Molecular-Weight Substrates by a Fungal Versatile Peroxidase, MnP2

• DOI: 10.1128/aem.02080-07
• Publication Date: 2008-03-08T02:09:58Z
• Authors: Takahisa Tsukihara; Yoichi Honda; Ryota Sakai; Takahito Watanabe; Takashi Watanabe
• Keywords: Molecular mass; Sodium dodecyl sulfate

ABSTRACT Unlike general peroxidases, Pleurotus ostreatus MnP2 was reported to have a unique property of direct oxidization high-molecular-weight compounds, such as Poly R-478 and RNase A. To elucidate the mechanism for oxidation polymeric substrates by MnP2, series mutant enzymes were produced using homologous gene expression system, their reactivities characterized. A enzyme with an Ala substituting exposing Trp (W170A) drastically lost activity veratryl alcohol (VA), R-478, A, whereas kinetic properties Mn 2+ H 2 O substantially unchanged. These results demonstrated that, in addition VA, are directly oxidized at W170. Moreover, mutants Q266F V166/168L, amino acid substitution(s) around W170 resulted decreased only substrates. results, along three-dimensional modeling mutants, suggested that mutations caused steric hindrance access Another mutant, R263N, contained newly generated N glycosylation site showed higher molecular mass sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. Interestingly, R263N exhibited increased reactivity VA The existence additional carbohydrate modification catalytic this discussed. This is first study fungal peroxidase system.