Hanaoka Yoshiko, Kimoto Hideyuki, Yoshimume Kazuaki, Hara Isao, Matsuyama Hidetoshi, Yumoto Isao
Graduate School of Agriculture, Hokkaido University, Sapporo, Japan.
Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukisamu-Higashi, Toyohira-ku, Sapporo, 062-8517 Japan.
Indian J Microbiol. 2020 Sep;60(3):353-362. doi: 10.1007/s12088-020-00878-3. Epub 2020 May 6.
Catalase has crucial role in adaptive response to HO. Main channel structure responsible for substrate selectivity was estimated to understand the relationship between the evolutionary direction of catalases from and which survive in cold and high concentration of hydrogen peroxide, and their catalytic property. . catalase (EKTA) exhibited a higher ratio of compound I formation rate using peracetic acid (a substrate lager than HO)/catalase activity using HO as the substrate than . catalase (PKTA). It was considered that the ratio was attributed to the size of the amino acid residues locating at the bottle neck structure in the main channel. The differences in the ratio of the compound I formation rate with peracetic acid to catalase activity with HO between the deeper branches in the phylogenetic tree in both EKTA and PKTA were large. This indicates that catalases from the hydrogen peroxide-tolerant bacteria have evolved in different directions, exhibiting effective catalytic activity and allowing broader substrates size or HO-specific substrate acceptability in EKTA and PKTA, respectively. It is considered that the main channel structure reflected the difference in the evolutionary direction of clade 1 and clade 3 catalases.
过氧化氢酶在对过氧化氢的适应性反应中起关键作用。通过估计负责底物选择性的主要通道结构，以了解在寒冷和高浓度过氧化氢环境中存活的过氧化氢酶的进化方向与其催化特性之间的关系。嗜冷栖热袍菌过氧化氢酶（EKTA）与嗜热栖热袍菌过氧化氢酶（PKTA）相比，使用过氧乙酸（一种比过氧化氢更大的底物）时化合物I形成速率与使用过氧化氢作为底物时的过氧化氢酶活性之比更高。据认为，该比例归因于位于主通道瓶颈结构处的氨基酸残基的大小。在系统发育树中，EKTA和PKTA较深分支中过氧乙酸与过氧化氢酶活性的化合物I形成速率之比差异很大。这表明来自耐过氧化氢细菌的过氧化氢酶已朝着不同方向进化，分别在EKTA和PKTA中表现出有效的催化活性，并允许更宽的底物大小或对过氧化氢特异性底物的接受性。据认为，主通道结构反映了1类和3类过氧化氢酶进化方向的差异。
