Effects of module truncation on biochemical characteristics and products distribution of a new alginate lyase with two catalytic modules
Effects of module truncation on biochemical characteristics and products distribution of a new alginate lyase with two catalytic modules
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模块截短对具有两个催化模块的新型藻酸盐裂解酶生化特性和产物分布的影响
DOI：
10.1093/glycob/cwz064
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发表时间：
2019-12-01
期刊：
影响因子：
4.3
通讯作者：
Yao, Zhong
中科院分区：
文献类型：
--
作者：
Hu, Fu;Li, Qian;Yao, Zhong
在这项工作中，我们研究了功能的结构模块内的海藻酸裂解酶截断为两个连续的催化模块的内型海藻酸裂解酶。进一步研究了模块缺失对生化特性和产物分布的影响。N-末端模块（Aly 7 B-CDI）对藻酸盐、polyM或polyG没有表现出活性，但C-末端模块（Aly 7 B-CDII）保留其活性。全长酶（Aly 7 B）和其截短的对应物（Aly 7 B-CDII）具有相似的底物特异性，但Aly 7 B-CDII具有较低的活性。此外，在30 ℃下Aly 7 B的活性远高于Aly 7 B-CDII。然而，Aly 7 B-CDII具有比全长酶更高的最适pH和更好的pH稳定性。Aly 7 B的最终降解产物为不饱和二、三和四寡糖，而Aly 7 B-CDII的最终降解产物为不饱和单、二、三、四和五寡糖。因此，通过表征Aly 7 B及其截短体，进一步阐明了非催化模块Aly 7 B-CDI对催化模块Aly 7 B-CDII的潜在影响。这些数据有助于理解这些不同模块的功能。
In this work, we investigated the functions of structural modules within alginate lyase by truncating an endo-type alginate lyase into two successive catalytic modules. The effects of module deletion on biochemical characteristics and product distributions were further investigated. The N-terminal module (Aly7B-CDI) exhibited no activity toward alginate, polyM or polyG, but the C-terminal module (Aly7B-CDII) retained its activity. The full-length enzyme (Aly7B) and its truncated counterpart (Aly7B-CDII) had similar substrate specificities, but Aly7B-CDII had lower activity. Moreover, the activity of Aly7B was much higher than Aly7B-CDII at 30 degrees C. Aly7B-CDII, however, possessed higher optimal pH and better pH stability than the full-length enzyme. The final degradation products for Aly7B were unsaturated di-, tri- and tetra-oligosaccharides, and those for Aly7B-CDII were unsaturated mono-, di-, tri-, tetra- and penta-oligosaccharides. Therefore, the potential impact of the noncatalytic module Aly7B-CDI on the catalytic module Aly7B-CDII was further elucidated by characterizing Aly7B and its truncations. These data contribute to the functional understanding of these differing modules.