A novel α-d-galactosynthase from Thermotoga maritima converts β-d-galactopyranosyl azide to α-galacto-oligosaccharides
A novel α-d-galactosynthase from Thermotoga maritima converts β-d-galactopyranosyl azide to α-galacto-oligosaccharides
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DOI：
10.1093/glycob/cwq177
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发表时间：
2011-04-01
期刊：
影响因子：
4.3
通讯作者：
Moracci, Marco
中科院分区：
文献类型：
--
作者：
Cobucci-Ponzano, Beatrice;Zorzetti, Carmela;Moracci, Marco
寡糖的大规模生产是一项艰巨的任务，阻碍了聚糖在体内作用的研究和基于聚糖的新型药物的功效测试。糖苷酶是一种突变的糖苷酶，能够高产地合成寡糖，正成为生产寡糖的重要化学-酶促工具。然而，虽然β-糖苷合酶可以用相当成熟的技术产生，但α-糖苷酶的实例迄今仅限于来自糖苷水解酶29（GH 29）、GH 31和GH 95家族的酶。来自GH 29的α-l-岩藻糖苷酶使用方便的糖基叠氮化物衍生物作为糖基氟化物供体的战略替代物。然而，这种方法对其他α-糖苷酶的普遍适用性并不是微不足道的，仍有待证实。在这里，β-D-半乳糖基叠氮化物转化为α-半乳糖低聚糖，具有良好的产率和高区域选择性，催化的一种新的α-半乳糖合酶的基础上的GH 36 α-半乳糖苷酶的超嗜热细菌海栖热袍菌。这些结果为实际合成生物学上有趣的α-半乳糖低聚糖开辟了一条新途径，并证明了β-糖基叠氮化物作为供体的更广泛用途，证实了它们在扩大糖苷酶谱方面的实用性。
The large-scale production of oligosaccharides is a daunting task, hampering the study of the role of glycans in vivo and the testing of the efficacy of novel glycan-based drugs. Glycosynthases, mutated glycosidases that synthesize oligosaccharides in high yields, are becoming important chemo-enzymatic tools for the production of oligosaccharides. However, while beta-glycosynthase can be produced with a rather well-established technology, examples of alpha-glycosynthases are thus far limited only to enzymes from glycoside hydrolase 29 (GH29), GH31 and GH95 families. alpha-l-Fucosynthases from GH29 use convenient glycosyl azide derivatives as a strategic alternative to glycosyl fluoride donors. However, the general applicability of this method to other alpha-glycosynthases is not trivial and remains to be confirmed. Here, beta-d-galactopyranosyl azide was converted to alpha-galacto-oligosaccharides with good yields and high regioselectivity, catalyzed by a novel alpha-galactosynthase based on the GH36 alpha-galactosidase from the hyperthermophilic bacterium Thermotoga maritima. These results open a new avenue to the practical synthesis of biologically interesting alpha-galacto-oligosaccharides and demonstrate more widespread use of beta-glycosyl-azide as donors, confirming their utility to expand the repertoire of glycosynthases.