National Institute of Advanced Industrial Science and Technology, Biomass Technology Research Center, 3-11-32 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-0046, Japan.
FEBS Lett. 2012 Apr 5;586(7):1009-13. doi: 10.1016/j.febslet.2012.02.029. Epub 2012 Mar 6.
Hyperthermophilic glycoside hydrolase family 12 endocellulase (EGPf) from the archaeon Pyrococcus furiosus catalyzes the hydrolytic cleavage of β-1,4-glucosidic linkage in β-glucan cellulose. A truncated EGPf (EGPfΔN30) mutant lacking the proline and hydroxyl-residue rich region at the N terminus was constructed, and its crystal structure was resolved at an atomic resolution of 1.07 Å. Our results indicate that the structure of EGPf, which consists of a β-jelly roll, exhibits structural similarity with the endocellulase of Thermotoga maritima. Additionally, we further determined that the thermostability of EGPf is maintained in part by the binding of Ca²⁺ in a DxDxDG Ca²⁺-binding motif, atypical of most archaeal proteins.
嗜热糖苷水解酶家族 12 内切纤维素酶（EGPf）来自古菌 Pyrococcus furiosus，能够催化β-1,4-糖苷键在β-葡聚糖纤维素中的水解。构建了一个缺失 N 端脯氨酸和富含羟基残基区域的截短 EGPf（EGPfΔN30）突变体，并解析了其原子分辨率为 1.07 Å的晶体结构。我们的结果表明，由β-果冻卷组成的 EGPf 结构与海洋栖热菌的内切纤维素酶具有结构相似性。此外，我们还进一步确定，EGPf 的热稳定性部分是通过在一个 DxDxDG Ca²⁺结合基序中结合 Ca²⁺来维持的，这种基序在大多数古菌蛋白中并不典型。
