A.N.Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow, Russia.
Biotechnol J. 2011 May;6(5):538-53. doi: 10.1002/biot.201000373. Epub 2011 Mar 7.
Cellobiose dehydrogenase (CDH) is an extracellular fungal flavocytochrome specifically oxidizing cellooligosaccharides and lactose to corresponding (-lactones by a variety of electron acceptors. In contrast to basidiomycetous CDHs, CDHs of ascomycetes also display certain activity toward glucose. The objective of this study was to establish the structural reasons of such an activity of CDH from mesophilic ascomycete Chaetomium sp. INBI 2-26 (ChCDH). The complete amino acid sequence of ChCDH displayed high levels of similarity with the amino acid sequences of CDHs from the thermophilic fungi Thielavia heterotallica and Myriococcum thermophilum. Peptide mass fingerprinting of purified ChCDH provided evidence for the oxidation of methionine residues in the FAD-domain. Comparative homology modeling of the structure of the ChCDH FAD-domain in complex with the transition state analog based on the structure of the same complex of basidiomycetous CDH (1NAA) as template indicated possible structural reasons for the enhanced activity of ascomycetous CDHs toward glucose at neutral pH, which is a prerequisite for application of CDH in a variety of biocompatible biosensors and biofuel cells.
纤维二糖脱氢酶（CDH）是一种细胞外真菌黄素细胞色素，能够特异性地将纤维寡糖和乳糖氧化为相应的（-内酯，可利用多种电子受体。与担子菌纲 CDH 不同，子囊菌纲的 CDH 对葡萄糖也具有一定的活性。本研究的目的是确定嗜温子囊菌 Chaetomium sp. INBI 2-26（ChCDH）CDH 具有这种活性的结构原因。ChCDH 的完整氨基酸序列与嗜热真菌 Thielavia heterotallica 和 Myriococcum thermophilum 的 CDH 氨基酸序列具有高度相似性。纯化的 ChCDH 的肽质量指纹图谱为 FAD 结构域中蛋氨酸残基的氧化提供了证据。基于担子菌纲 CDH（1NAA）同一复合物的结构作为模板，对 ChCDH FAD 结构域与过渡态类似物复合物的结构进行比较同源建模，表明了中性 pH 下增强子囊菌 CDH 对葡萄糖活性的可能结构原因，这是 CDH 在各种生物相容性生物传感器和生物燃料电池中应用的前提。
