Korczynska Justyna E, Danielsen Steffen, Schagerlöf Ulrika, Turkenburg Johan P, Davies Gideon J, Wilson Keith S, Taylor Edward J
Structural Biology Laboratory, Department of Chemistry, The University of York, York YO10 5YW, England.
Acta Crystallogr Sect F Struct Biol Cryst Commun. 2010 Sep 1;66(Pt 9):973-7. doi: 10.1107/S1744309110025601. Epub 2010 Aug 21.
Lysins are important biomolecules which cleave the bacterial cell-wall polymer peptidoglycan. They are finding increasing commercial and medical application. In order to gain an insight into the mechanism by which these enzymes operate, the X-ray structure of a CAZy family GH25 ;lysozyme' from Aspergillus fumigatus was determined. This is the first fungal structure from the family and reveals a modified alpha/beta-barrel-like fold in which an eight-stranded beta-barrel is flanked by three alpha-helices. The active site lies toward the bottom of a negatively charged pocket and its layout has much in common with other solved members of the GH25 and related GH families. A conserved active-site DXE motif may be implicated in catalysis, lending further weight to the argument that this glycoside hydrolase family operates via a ;substrate-assisted' catalytic mechanism.
溶素是重要的生物分子，可裂解细菌细胞壁聚合物肽聚糖。它们在商业和医学上的应用越来越广泛。为了深入了解这些酶的作用机制，测定了来自烟曲霉的碳水化合物活性酶家族GH25“溶菌酶”的X射线结构。这是该家族的首个真菌结构，揭示了一种修饰的α/β桶状折叠，其中一个八链β桶两侧有三个α螺旋。活性位点位于带负电荷口袋的底部，其布局与GH25和相关GH家族的其他已解析成员有很多共同之处。保守的活性位点DXE基序可能参与催化作用，进一步支持了这个糖苷水解酶家族通过“底物辅助”催化机制起作用的观点。
