Identification of one of the apurinic/apyrimidinic lyase active sites of topoisomerase V by structural and functional studies.
Identification of one of the apurinic/apyrimidinic lyase active sites of topoisomerase V by structural and functional studies.
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DOI：
10.1093/nar/gks1017
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发表时间：
2013-01-07
影响因子：
14.9
通讯作者：
Mondragón A
中科院分区：
文献类型：
--
作者：
Rajan R;Prasad R;Taneja B;Wilson SH;Mondragón A
拓扑异构酶V（Topo-V）是拓扑异构酶新亚型的唯一成员。Topo-V是独特的，因为它是一种双功能酶，在同一蛋白质内携带拓扑异构酶和DNA修复裂解酶活性。以前的研究表明，拓扑异构酶结构域跨越蛋白质的N-末端，随后是12个串联螺旋-发夹-螺旋[（HhH）2]结构域。存在至少两个DNA修复裂解酶活性位点用于脱嘌呤/脱嘧啶（AP）位点加工，一个在N-末端区域内，第二个在Topo-V的C-末端结构域内，但它们的确切位置和特征未知。在本研究中，N-末端78-kDa片段的拓扑-V（拓扑-78），含有拓扑异构酶结构域和裂解酶DNA修复结构域之一，其特征在于结构和生化研究。结果表明，N端69-kDa片段是同时具有拓扑异构酶和AP裂解酶活性的最小片段。Topo-78的裂解酶活性位点位于第五和第六（HhH）2结构域的连接处。从生物化学和结构数据来看，Lys 571似乎是负责裂解酶活性的最可能的亲核试剂。我们的实验还表明Topo-V最有可能在体内充当I类AP核酸内切酶。
Topoisomerase V (Topo-V) is the only member of a novel topoisomerase subtype. Topo-V is unique because it is a bifunctional enzyme carrying both topoisomerase and DNA repair lyase activities within the same protein. Previous studies had shown that the topoisomerase domain spans the N-terminus of the protein and is followed by 12 tandem helix–hairpin–helix [(HhH)2] domains. There are at least two DNA repair lyase active sites for apurinic/apyrimidinic (AP) site processing, one within the N-terminal region and the second within the C-terminal domain of Topo-V, but their exact locations and characteristics are unknown. In the present study, the N-terminal 78-kDa fragment of Topo-V (Topo-78), containing the topoisomerase domain and one of the lyase DNA repair domains, was characterized by structural and biochemical studies. The results show that an N-terminal 69-kDa fragment is the minimal fragment with both topoisomerase and AP lyase activities. The lyase active site of Topo-78 is at the junction of the fifth and sixth (HhH)2 domains. From the biochemical and structural data, it appears that Lys571 is the most probable nucleophile responsible for the lyase activity. Our experiments also suggest that Topo-V most likely acts as a Class I AP endonuclease in vivo.
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DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
4.8
作者：
Belova, GI;Prasad, R;Slesarev, AI
通讯作者：
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影响因子：
14.9
作者：
Baker NM;Rajan R;Mondragón A
通讯作者：
Mondragón A
DOI：
10.1107/s0907444994003112
发表时间：
1994-09-01
期刊：
ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY
影响因子：
--
作者：
BAILEY, S
通讯作者：
BAILEY, S
通过用移相替换分子替代蛋白质复合物的结构。
DOI：
10.1107/s0907444906045975
发表时间：
2007-01
期刊：
Acta crystallographica. Section D, Biological crystallography
影响因子：
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作者：
McCoy AJ
通讯作者：
McCoy AJ