Thermococcus kodakarensis encodes three MCM homologs but only one is essential.
Thermococcus kodakarensis encodes three MCM homologs but only one is essential.
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DOI：
10.1093/nar/gkr624
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发表时间：
2011-12
影响因子：
14.9
通讯作者：
Kelman Z
中科院分区：
文献类型：
--
作者：
Pan M;Santangelo TJ;Li Z;Reeve JN;Kelman Z
微染色体维持（MCM）复合体被认为是古细菌和真核生物的复制解旋酶。在真核生物中，这种复合物是由六个不同但相关的多肽（MCM2-7）组成的，但在大多数古细菌中，一个MCM蛋白组装形成一个同六聚体复合物。典型情况下，柯达热球菌基因组编码三种古细菌MCM同源物，这里指定为MCM1-3，尽管MCM1和MCM2具有长而独特的n端延伸是不寻常的。结果表明，MCM2和MCM3在体外组装成同六聚体，并表现出古菌MCMs典型的DNA结合、解旋酶和atp酶活性。相比之下，MCM1不形成同六聚体，尽管MCM1结合DNA并具有atp酶活性，但在体外仅具有最低的解旋酶活性。去除n端延伸对MCM1没有明显影响，但增加了MCM2的解旋酶活性。我们构建了一个缺失了TK0096 （MCM1）和TK1361 （MCM2）基因的柯达卡菌菌株，该菌株在生长和生存能力方面没有可检测到的缺陷，但所有试图删除TK1620 （MCM3）的尝试都失败了，因为MCM3是必不可少的，可能是柯达卡菌的复制解旋酶。讨论了三种MCM蛋白的起源和可能的功能。
The minichromosome maintenance (MCM) complex is thought to function as the replicative helicase in archaea and eukaryotes. In eukaryotes, this complex is an assembly of six different but related polypeptides (MCM2-7) but, in most archaea, one MCM protein assembles to form a homohexameric complex. Atypically, the Thermococcus kodakarensis genome encodes three archaeal MCM homologs, here designated MCM1-3, although MCM1 and MCM2 are unusual in having long and unique N-terminal extensions. The results reported establish that MCM2 and MCM3 assemble into homohexamers and exhibit DNA binding, helicase and ATPase activities in vitro typical of archaeal MCMs. In contrast, MCM1 does not form homohexamers and although MCM1 binds DNA and has ATPase activity, it has only minimal helicase activity in vitro. Removal of the N-terminal extension had no detectable effects on MCM1 but increased the helicase activity of MCM2. A T. kodakarensis strain with the genes TK0096 (MCM1) and TK1361 (MCM2) deleted has been constructed that exhibits no detectable defects in growth or viability, but all attempts to delete TK1620 (MCM3) have been unsuccessful arguing that that MCM3 is essential and is likely the replicative helicase in T. kodakarensis. The origins and possible function(s) of the three MCM proteins are discussed.
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DNA结合和解旋酶活性的偶联是由MCM蛋白中的保守环介导的。
影响因子：
14.9
作者：
Sakakibara, Nozomi;Kasiviswanathan, Rajesh;Melamud, Eugene;Han, Mimi;Schwarz, Frederick P.;Kelman, Zvi
通讯作者：
Kelman, Zvi
影响因子：
2.9
作者：
Atanassova, Neli;Grainge, Ian
通讯作者：
Grainge, Ian
影响因子：
4.1
作者：
Liew, Li Phing;Bell, Stephen D.
通讯作者：
Bell, Stephen D.
影响因子：
21.3
作者：
Gambus, A;Jones, RC;Labib, K
通讯作者：
Labib, K
影响因子：
14.9
作者：
Perler, FB
通讯作者：
Perler, FB