Janecek Stefan, Svensson Birte, MacGregor E Ann
Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, SK-84551 Bratislava, Slovakia.
FEBS Lett. 2007 Apr 3;581(7):1261-8. doi: 10.1016/j.febslet.2007.02.036. Epub 2007 Feb 28.
Although both the alpha-amylase super-family, i.e. the glycoside hydrolase (GH) clan GH-H (the GH families 13, 70 and 77), and family GH31 share some characteristics, their different catalytic machinery prevents classification of GH31 in clan GH-H. A significant but remote evolutionary relatedness is, however, proposed for clan GH-H with GH31. A sequence alignment, based on the idea that residues equivalent in the primordial catalytic GH-H/GH31 (beta/alpha)(8)-barrel may not be found in the present-day GH-H and GH31 structures at strictly equivalent positions, shows remote sequence homologies covering beta3, beta4, beta7 and beta8 of the GH-H and GH31 (beta/alpha)(8)-barrels. Structure comparison of GH13 alpha-amylase and GH31 alpha-xylosidase guided alignment of GH-H and GH31 members for construction of evolutionary trees. The closest sequence relationship displayed by GH31 is to GH77 of clan GH-H.
虽然α-淀粉酶超家族，即糖苷水解酶（GH）家族GH-H（GH家族13、70和77），与GH31家族有一些共同特征，但它们不同的催化机制使得GH31无法归类于GH-H家族。然而，有人提出GH-H家族与GH31家族存在显著但遥远的进化相关性。基于在当今的GH-H和GH31结构中，原始催化性GH-H/GH31（β/α）8桶中同等的残基可能不在严格等同的位置这一观点进行的序列比对，显示出覆盖GH-H和GH31（β/α）8桶的β3、β4、β7和β8的遥远序列同源性。GH13α-淀粉酶和GH31α-木糖苷酶的结构比较指导了GH-H和GH31成员的比对，以构建进化树。GH31显示出与GH-H家族的GH77最接近的序列关系。
