Institute of Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 38 Bratislava, Slovak Republic.
Institute of Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 38 Bratislava, Slovak Republic.
Biotechnol Adv. 2021 Mar-Apr;47:107704. doi: 10.1016/j.biotechadv.2021.107704. Epub 2021 Feb 3.
Xylan is the most abundant hemicellulose in nature and as such it is a huge source of renewable carbon. Its bioconversion requires a battery of xylanolytic enzymes. Of them the most important are the endo-β-1,4-xylanases which depolymerize the polysaccharide into smaller fragments. Most of the xylanases are members of glycoside hydrolase (GH) families 10 and 11, although they are classified in some other GH families. The relatively new xylanases of GH30 are of special interest. Initially, they appeared to be specific glucuronoxylanases, however, other specificities were found later among prokaryotic and in particular eukaryotic enzymes. This review gives an overview of the substrate and product specificities observed for the GH30 xylanases characterized to date. An emphasis is given to the structure-activity relationship in order to explain how minor differences in catalytic centre and its vicinity can alter catalytic properties from the endoxylanase into the reducing end xylose releasing exoxylanase or into the non-reducing end xylobiohydrolase. Biotechnological potential of the GH30 xylanases is also considered.
木聚糖是自然界中最丰富的半纤维素，因此它是可再生碳的巨大来源。它的生物转化需要一系列木聚糖酶。其中最重要的是内切-β-1,4-木聚糖酶，它将多糖分解成较小的片段。大多数木聚糖酶属于糖苷水解酶 (GH) 家族 10 和 11，尽管它们也被分类在其他一些 GH 家族中。相对较新的 GH30 木聚糖酶特别引人注目。最初，它们似乎是特异性的葡糖醛酸木聚糖酶，但后来在原核生物中发现了其他特异性，特别是真核酶。这篇综述概述了迄今为止表征的 GH30 木聚糖酶的底物和产物特异性。重点介绍了结构-活性关系，以解释催化中心及其附近的微小差异如何将催化特性从内切木聚糖酶改变为还原末端释放木糖的外切木聚糖酶，或改变为非还原末端的木二糖水解酶。还考虑了 GH30 木聚糖酶的生物技术潜力。
