Sinclair R, Yamazaki I, Bumpus J, Brock B, Chang C S, Albo A, Powers L
National Center for the Design of Molecular Function, Utah State University, Logan 84322-4630.
Biochemistry. 1992 May 26;31(20):4892-900. doi: 10.1021/bi00135a021.
The wood-degrading fungus Phanerochaete chrysosporium secretes a number of extracellular enzymes called lignin peroxidases which are involved in the degradation of both lignin and a number of persistent environmental pollutants. Lignin peroxidase isozyme H2, a glycosylated protein of approximately 40 kDa, contains a single heme. X-ray absorption spectroscopy (XAS) has been used to probe the local environment of the iron in the active site of resting enzyme, reduced enzyme, and compound III. For the native and reduced forms, respectively, the average Fe-pyrrole nitrogen distances are 2.055 and 2.02 A (+/- 0.015 A); the Fe-proximal nitrogen distance is 1.93 and 1.91 A (+/- 0.02 A) while the Fe-distal ligand distance is 2.17 and 2.10 A (+/- 0.03 A). Although the results are not as well-defined, the active-site structure of compound III is largely 2.02 +/- 0.015 A for the average Fe-pyrrole nitrogen distance, 1.90 +/- 0.02 for the Fe-proximal nitrogen, and 1.74 +/- 0.03 A for the Fe-distal ligand distance. The heme iron-pyrrole nitrogen distance is more expanded in ligninase H2 than in other peroxidases. The possible significance of this is discussed in relation to other heme proteins.
木腐真菌黄孢原毛平革菌分泌多种细胞外酶，称为木质素过氧化物酶，这些酶参与木质素和多种持久性环境污染物的降解。木质素过氧化物酶同工酶H2是一种糖基化蛋白，分子量约为40 kDa，含有一个血红素。X射线吸收光谱法（XAS）已被用于探测静止酶、还原酶和化合物III活性位点中铁的局部环境。对于天然形式和还原形式，平均铁-吡咯氮距离分别为2.055和2.02 Å（±0.015 Å）；铁-近端氮距离为1.93和1.91 Å（±0.02 Å），而铁-远端配体距离为2.17和2.10 Å（±0.03 Å）。虽然结果不是很明确，但化合物III的活性位点结构，平均铁-吡咯氮距离在很大程度上为2.02±0.015 Å，铁-近端氮为1.90±0.02，铁-远端配体距离为1.74±0.03 Å。木质素酶H2中的血红素铁-吡咯氮距离比其他过氧化物酶中的更扩展。本文结合其他血红素蛋白讨论了其可能的意义。
