Assembly of EcoKI DNA methyltransferase requires the C-terminal region of the HsdM modification subunit
Assembly of EcoKI DNA methyltransferase requires the C-terminal region of the HsdM modification subunit
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DOI：
10.1016/s0301-4622(02)00251-x
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发表时间：
2003-01-21
影响因子：
3.8
通讯作者：
Dryden, DTF
中科院分区：
文献类型：
--
作者：
Powell, LM;Lejeune, E;Dryden, DTF
I型DNA限制和修饰系统的甲基转移酶组分包含三个亚基，一个DNA序列特异性亚基和两个DNA修饰亚基。 EcoK1甲基转移酶的有限蛋白水解表明59-kDa修饰亚基的55-kDa N-末端片段对降解具有抗性。我们纯化了该片段，并通过质谱测定确定蛋白水解从 C 末端去除了 43 或 44 个氨基酸。该片段无法与其他亚基相互作用，尽管它仍然具有二级和三级结构以及结合 S-腺苷甲硫氨酸辅因子的能力。我们得出结论，EcoKI 修饰亚基的 C 端区域对于 EcoKI 甲基转移酶的组装至关重要。 (C) 2002 Elsevier Science B.V. 保留所有权利。
The methyltransferase component of type I DNA restriction and modification systems comprises three subunits, one DNA sequence specificity subunit and two DNA modification subunits. Limited proteolysis of the EcoKl methyltransferase shows that a 55-kDa N-terminal fragment of the 59-kDa modification subunit is resistant to degradation. We have purified this fragment and determined by mass spectrometry that proteolysis removes 43 or 44 amino acids from the C-terminus. The fragment fails to interact with the other subunits even though it still possesses secondary and tertiary structure and the ability to bind the S-adenosylmethionine cofactor. We conclude that the C-terminal region of the modification subunit of EcoKl is essential for the assembly of the EcoKI methyltransferase. (C) 2002 Elsevier Science B.V. All rights reserved.