Dimarogona Maria, Topakas Evangelos, Christakopoulos Paul, Chrysina Evangelia D
Institute of Organic and Pharmaceutical Chemistry, National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, 11635 Athens, Greece.
Acta Crystallogr D Biol Crystallogr. 2012 Jul;68(Pt 7):735-42. doi: 10.1107/S0907444912007044. Epub 2012 Jun 15.
Xylanase enzymes have been the focus of considerable research in recent decades owing to their extensive use in a variety of biotechnological applications. Previous structural studies of a number of GH10 xylanases revealed that all GH10 family members have the (β/α)(8)-barrel fold and their catalytic site is conserved. The structure of a new GH10 xylanase from Fusarium oxysporum (FoXyn10a) was determined at 1.94 Å resolution from crystals belonging to the tetragonal space group P4(1)2(1)2 with five molecules per asymmetric unit. Comparison of the structure of FoXyn10a with previously determined structures of GH10 family members indicated that most of the differences were located in the loop regions between the ordered secondary-structure elements of the barrel, as expected. However, alignment of FoXyn10a with sequence and structural homologues denoted an atypically long loop connecting strand β6b and helix α6 that was only present in one other GH10 xylanase, the structure of which is not known. This structural feature may be of functional importance, with potential implications in the catalytic efficiency of the enzyme.
近几十年来，木聚糖酶因其在各种生物技术应用中的广泛使用而成为大量研究的焦点。先前对多种GH10木聚糖酶的结构研究表明，所有GH10家族成员都具有(β/α)(8)桶状折叠结构，且其催化位点保守。从属于四方晶系空间群P4(1)2(1)2、每个不对称单元有五个分子的晶体中，以1.94 Å的分辨率确定了来自尖孢镰刀菌的一种新的GH10木聚糖酶（FoXyn10a）的结构。将FoXyn10a的结构与先前确定的GH10家族成员的结构进行比较表明，正如预期的那样，大多数差异位于桶状结构中有序二级结构元件之间的环区。然而，将FoXyn10a与序列和结构同源物进行比对时发现，连接β6b链和α6螺旋的环异常长，这种环只在另一种GH10木聚糖酶中存在，而其结构尚不清楚。这一结构特征可能具有功能重要性，对该酶的催化效率可能有潜在影响。
