Shibata Naoki, Mori Koichi, Hieda Naoki, Higuchi Yoshiki, Yamanishi Mamoru, Toraya Tetsuo
Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Ako-gun, Hyogo 678-1297, Japan.
Structure. 2005 Dec;13(12):1745-54. doi: 10.1016/j.str.2005.08.011.
The crystal structures of ADP bound and nucleotide-free forms of molecular chaperone-like diol dehydratase-reactivating factor (DDR) were determined at 2.0 and 3.0 A, respectively. DDR exists as a dimer of heterodimer (alphabeta)2. The alpha subunit has four domains: ATPase domain, swiveling domain, linker domain, and insert domain. The beta subunit, composed of a single domain, has a similar fold to the beta subunit of diol dehydratase (DD). The binding of an ADP molecule to the nucleotide binding site of DDR causes a marked conformational change of the ATPase domain of the alpha subunit, which would weaken the interactions between the DDR alpha and beta subunits and make the displacement of the DDR beta subunit by DD through the beta subunit possible. The binding of the DD beta subunit to the DDR alpha subunit induces steric repulsion between the DDR alpha and DD alpha subunits that would lead to the release of a damaged cofactor from inactivated holoDD.
分别在2.0埃和3.0埃的分辨率下测定了分子伴侣样二醇脱水酶激活因子（DDR）结合ADP和无核苷酸形式的晶体结构。DDR以异源二聚体（αβ）2的二聚体形式存在。α亚基有四个结构域：ATP酶结构域、旋转结构域、连接结构域和插入结构域。由单个结构域组成的β亚基与二醇脱水酶（DD）的β亚基具有相似的折叠结构。ADP分子与DDR的核苷酸结合位点结合会导致α亚基的ATP酶结构域发生显著的构象变化，这会削弱DDR的α亚基和β亚基之间的相互作用，并使DD通过β亚基取代DDR的β亚基成为可能。DD的β亚基与DDR的α亚基结合会在DDR的α亚基和DD的α亚基之间诱导空间排斥，这将导致失活的全酶DD中受损辅因子的释放。
