Bujnicki J M, Radlinska M, Zaleski P, Piekarowicz A
Bioinformatics Laboratory, International Institute of Molecular and Cell Biology, Warszawa, Poland.
Acta Biochim Pol. 2001;48(4):969-83.
In this paper we report cloning and experimental characterization of the DNA adenine methyltransferase (dam) gene from Haemophilus influenzae and comparison of its product with the Dam protein from the lysogenic phage of H. influenzae, HP1. Molecular modeling of M.HinDam and M.HP1Dam was carried out, providing a framework for a comparative analysis of these enzymes and their close homologs in the structural context. Both proteins share the common fold and essential cofactor-binding and catalytic residues despite overall divergence. However, subtle but significant differences in the cofactor-binding pocket have been identified. Moreover, while M.HinDam seems to contact its target DNA sequence using a number of loops, most of them are missing from M.HP1Dam. Analysis of both MTases suggests that their catalytic activity was derived from a common ancestor, but similar sequence specificities arose by convergence.
在本文中，我们报道了流感嗜血杆菌DNA腺嘌呤甲基转移酶（dam）基因的克隆及实验特性分析，并将其产物与流感嗜血杆菌溶原性噬菌体HP1的Dam蛋白进行了比较。对M.HinDam和M.HP1Dam进行了分子建模，为在结构背景下对这些酶及其密切同源物进行比较分析提供了框架。尽管总体上存在差异，但这两种蛋白质具有共同的折叠结构以及必需的辅因子结合和催化残基。然而，已确定在辅因子结合口袋中存在细微但显著的差异。此外，虽然M.HinDam似乎利用多个环与靶DNA序列接触，但M.HP1Dam中大多数此类环缺失。对这两种甲基转移酶的分析表明，它们的催化活性源自共同的祖先，但相似的序列特异性是趋同产生的。
