...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Experimental Botany >Substrate oxidation sites in versatile peroxidase and other basidiomycete peroxidases
【24h】

Substrate oxidation sites in versatile peroxidase and other basidiomycete peroxidases

机译：通用过氧化物酶和其他担子菌过氧化物酶中的底物氧化位点

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Versatile peroxidase (VP) is defined by its capabilities to oxidize the typical substrates of other basidiomycete peroxidases: (i) Mn(2+), the manganese peroxidase (MnP) substrate (Mn(3+) being able to oxidize phenols and initiate lipid peroxidation reactions); (ii) veratryl alcohol (VA), the typical lignin peroxidase (LiP) substrate; and (iii) simple phenols, which are the substrates of Coprinopsis cinerea peroxidase (CIP). Crystallographic, spectroscopic, directed mutagenesis, and kinetic studies showed that these 'hybrid' properties are due to the coexistence in a single protein of different catalytic sites reminiscent of those present in the other basidiomycete peroxidase families. Crystal structures of wild and recombinant VP, and kinetics of mutated variants, revealed certain differences in its Mn-oxidation site compared with MnP. These result in efficient Mn(2+) oxidation in the presence of only two of the three acidic residues forming its binding site. On the other hand, a solvent-exposed tryptophan is the catalytically-active residue in VA oxidation, initiating an electron transfer pathway to haem (two other putative pathways were discarded by mutagenesis). Formation of a tryptophanyl radical after VP activation by peroxide was detected using electron paramagnetic resonance. This was the first time that a protein radical was directly demonstrated in a ligninolytic peroxidase. In contrast with LiP, the VP catalytic tryptophan is not beta-hydroxylated under hydrogen peroxide excess. It was also shown that the tryptophan environment affected catalysis, its modification introducing some LiP properties in VP. Moreover, some phenols and dyes are oxidized by VP at the edge of the main haem access channel, as found in CIP. Finally, the biotechnological interest of VP is discussed.
机译：多功能过氧化物酶（VP）由其氧化其他担子菌过氧化物酶的典型底物的能力定义：（i）Mn（2+），锰过氧化物酶（MnP）底物（Mn（3+）能够氧化酚和引发脂质过氧化反应）; （ii）藜芦醇（VA），典型的木质素过氧化物酶（LiP）底物; （iii）简单的酚，它们是灰粉菌过氧化物酶（CIP）的底物。晶体学，光谱学，定向诱变和动力学研究表明，这些“杂化”性质是由于不同催化位点的单一蛋白质共存所致，让人联想到其他担子菌过氧化物酶家族中存在的那些。野生和重组VP的晶体结构，以及突变变体的动力学，与MnP相比揭示了其Mn氧化位点的某些差异。这些导致在形成其结合位点的三个酸性残基中只有两个的情况下有效的Mn（2+）氧化。另一方面，暴露于溶剂的色氨酸是VA氧化中的催化活性残基，从而引发了血红素的电子转移途径（通过诱变去除了其他两个推定的途径）。使用电子顺磁共振检测过氧化物激活VP后色氨酸基的形成。这是第一次在木质素分解过氧化物酶中直接显示蛋白质自由基。与LiP相比，VP催化色氨酸在过氧化氢过量下不会被β-羟基化。还表明色氨酸环境影响催化，其修饰在VP中引入了一些LiP性质。此外，如在CIP中所发现的那样，一些酚和染料在主要血红素通道的边缘被VP氧化。最后，讨论了VP的生物技术兴趣。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号