Chitobiose phosphorylase from vibrio Proteolyticus, a member of glycosyl transferase family 36, has a clan GH-L-like (α/α)6 barrel fold
Chitobiose phosphorylase from vibrio Proteolyticus, a member of glycosyl transferase family 36, has a clan GH-L-like (α/α)6 barrel fold
复制标题
DOI：
10.1016/j.str.2004.03.027
复制
发表时间：
2004-06-01
期刊：
影响因子：
5.7
通讯作者：
Fushinobu, S
中科院分区：
文献类型：
--
作者：
Hidaka, M;Honda, Y;Fushinobu, S
蛋白水解菌几丁二糖磷酸化酶(ChBP)属于糖基转移酶家族36(GT-36)，催化壳二糖的可逆磷酸化反应生成α-GlcNAc-1-磷酸和反式构型的GlcNAc。作为GT-36酶的第一个已知结构，我们测定了ChBP与GlcNAc和SO4形成的三元络合物的晶体结构。这也是首次在糖和硫酸盐离子的络合物中发现转化磷酸水解酶的结构，并揭示了酶-糖-磷酸盐的伪三元络合物结构。ChBP由一个β夹心结构域和一个(α/α)(6)桶结构域组成，构成了GT家族中一个独特的结构。相反，它与GH-L家族中的糖苷水解酶(GH)、糖淀粉酶(GH-15)和麦芽糖磷酸化酶(GH-65)在结构上显示出显著的相似性。由于结构上的相似性，以及ChBP和GHS之间的远距离序列相似性，GT-36家族被重新归类为一个新的GH家族，即GH-94。
Vibrio proteolyticus chitobiose phosphorylase (ChBP) belongs to glycosyl transferase family 36 (GT-36), and catalyzes the reversible phosphorolysis of chitobiose into alpha-GlcNAc-1-phosphate and GlcNAc with inversion of the anomeric configuration. As the first known structures of a GT-36 enzyme, we determined the crystal structure of ChBP in a ternary complex with GlcNAc and SO4. It is also the first structures of an inverting phosphorolytic enzyme in a complex with a sugar and a sulfate ion, and reveals a pseudo-ternary complex structure of enzyme-sugar-phosphate. ChBP comprises a beta sandwich domain and an (alpha/alpha)(6) barrel domain, constituting a distinctive structure among GT families. Instead, it shows significant structural similarity with glycoside hydrolase (GH) enzymes, glucoamylases (GH-15), and maltose phosphorylase (GH-65) in clan GH-L. The structural similarity reported here, together with distant sequence similarities between ChBP and GHs, led to the reclassification of family GT-36 into a novel GH family, namely GH-94.