Olsson Ulrika, Wolf-Watz Magnus
Department of Chemistry, Chemical Biological Centre, Umeå University, Umeå 90187, Sweden.
Nat Commun. 2010 Nov 16;1:111. doi: 10.1038/ncomms1106.
Enzyme function is often dependent on fluctuations between inactive and active structural ensembles. Adenylate kinase isolated from Escherichia coli (AK(e)) is a small phosphotransfer enzyme in which interconversion between inactive (open) and active (closed) conformations is rate limiting for catalysis. AK(e) has a modular three-dimensional architecture with two flexible substrate-binding domains that interact with the substrates AMP, ADP and ATP. Here, we show by using a combination of biophysical and mutagenic approaches that the interconversion between open and closed states of the ATP-binding subdomain involves partial subdomain unfolding/refolding in an otherwise folded enzyme. These results provide a novel and, possibly general, molecular mechanism for the switch between open and closed conformations in AK(e).
酶的功能通常取决于无活性和活性结构集合之间的波动。从大肠杆菌中分离出的腺苷酸激酶（AK(e)）是一种小的磷酸转移酶，其中无活性（开放）和活性（闭合）构象之间的相互转化是催化的限速步骤。AK(e)具有模块化的三维结构，有两个与底物AMP、ADP和ATP相互作用的灵活底物结合结构域。在这里，我们通过结合生物物理和诱变方法表明，ATP结合亚结构域的开放和闭合状态之间的相互转化涉及在其他部分折叠的酶中部分亚结构域的去折叠/再折叠。这些结果为AK(e)中开放和闭合构象之间的转换提供了一种新颖且可能普遍的分子机制。
