Davies Gideon J, Gloster Tracey M, Henrissat Bernard
Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5YW, UK.
Curr Opin Struct Biol. 2005 Dec;15(6):637-45. doi: 10.1016/j.sbi.2005.10.008. Epub 2005 Nov 2.
Enzymes that catalyse the synthesis and breakdown of glycosidic bonds account for 1-3% of the proteins encoded by the genomes of most organisms. At the current rate, over 12 000 glycosyltransferase and glycoside hydrolase open reading frames will appear during 2006. Recent advances in the study of the structure and mechanism of these carbohydrate-active enzymes reveal that glycoside hydrolases continue to display a wide variety of scaffolds, whereas nucleotide-sugar-dependent glycosyltransferases tend to be grafted onto just two protein folds. The past two years have seen significant advances, including the discovery of a novel NAD+-dependent glycosidase mechanism, the dissection of the reaction coordinate of sialidases and a better understanding of the expanding roles of auxiliary carbohydrate-binding domains.
催化糖苷键合成与分解的酶占大多数生物体基因组所编码蛋白质的1%至3%。按照目前的速度，2006年期间将会出现超过12000个糖基转移酶和糖苷水解酶的开放阅读框。这些碳水化合物活性酶的结构与作用机制研究的最新进展表明，糖苷水解酶仍呈现出多种多样的支架结构，而依赖核苷酸糖的糖基转移酶往往仅嫁接到两种蛋白质折叠结构上。过去两年取得了重大进展，包括发现了一种新的依赖烟酰胺腺嘌呤二核苷酸（NAD+）的糖苷酶机制、剖析了唾液酸酶的反应坐标以及对辅助碳水化合物结合结构域不断扩展的作用有了更好的理解。
