The metabolism of sucrose is of crucial importance for life on Earth. In plants, enzymes called invertases split sucrose into glucose and fructose, contributing to the regulation of metabolic fluxes. Invertases differ in their localization and pH optimum. Acidic invertases present in plant cell walls and vacuoles belong to glycoside hydrolase family 32 (GH32) and have an all‐β structure. In contrast, neutral invertases are located in the cytosol and organelles such as chloroplasts and mitochondria. These poorly understood enzymes are classified into a separate GH100 family. Recent crystal structures of the closely related neutral invertases InvA and InvB from the cyanobacterium Anabaena revealed a predominantly α‐helical fold with unique features compared with other sucrose‐metabolizing enzymes. Here, a neutral invertase (AtNIN2) from the model plant Arabidopsis thaliana was heterologously expressed, purified and crystallized. As a result, the first neutral invertase structure from a higher plant has been obtained at 3.4 Å resolution. The hexameric AtNIN2 structure is highly similar to that of InvA, pointing to high evolutionary conservation of neutral invertases.

中文翻译：

---

拟南芥中性转化酶2的晶体结构。

蔗糖的代谢对于地球上的生命至关重要。在植物中，转化酶将蔗糖分解为葡萄糖和果糖，有助于调节代谢通量。蔗糖酶的定位和最适 pH 值不同。植物细胞壁和液泡中存在的酸性转化酶属于糖苷水解酶家族 32 (GH32)，具有全β结构。相反，中性蔗糖酶位于细胞质和细胞器，如叶绿体和线粒体中。这些人们知之甚少的酶被分为一个单独的 GH100 家族。最近，来自蓝藻鱼腥藻的密切相关的中性蔗糖酶 InvA 和 InvB 的晶体结构显示，与其他蔗糖代谢酶相比，其主要具有独特的 α 螺旋折叠特征。在这里，来自模式植物拟南芥的中性转化酶（AtNIN2）被异源表达、纯化和结晶。结果，我们获得了第一个来自高等植物的中性蔗糖酶结构，分辨率为 3.4 Å。AtNIN2 六聚体结构与 InvA 高度相似，表明中性转化酶具有高度进化保守性。