THE REPLICATION TERMINATOR PROTEIN OF ESCHERICHIA-COLI IS A DNA SEQUENCE-SPECIFIC CONTRA-HELICASE
THE REPLICATION TERMINATOR PROTEIN OF ESCHERICHIA-COLI IS A DNA SEQUENCE-SPECIFIC CONTRA-HELICASE
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DOI：
10.1016/0092-8674(89)90012-3
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发表时间：
1989-11-17
期刊：
影响因子：
64.5
通讯作者：
BASTIA, D
中科院分区：
文献类型：
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作者：
KHATRI, GS;MACALLISTER, T;BASTIA, D
我们克隆了编码大肠杆菌复制终止蛋白的tus基因，并高效表达了其基因产物。过度生产菌株已用于以高产量纯化终止子 (ter) 蛋白，使其接近同质。该蛋白质是单一的 36 kd 多肽。使用ter蛋白和高度纯化的dnaB解旋酶，我们证明终止子蛋白是DNA序列特异性的反解旋酶，即，当该蛋白与其识别序列(.tau.)结合时，强烈阻碍双链DNA的ATP依赖性解旋。这种反解旋酶活性是极性的，即解旋阻抗仅发生在 tau 的一个方向上。顺序。结果阐明了 .tau 处的复制终止机制。
We have cloned the tus gene that encodes the replication termintor protein of Escherichia coli and have efficiently expressed its gene product. The overproducer strain has been used to purify the terminator (ter) protein in high yield to near homogeneity. The protein is a single 36 kd polypeptide. Using the ter protein and highly purified dnaB helicase, we show that the terminator protein is a DNA sequence-specific contra-helicase, i.e., the protein when bound to its recognition sequence (.tau.) strongly impedes the ATP-dependent unwinding of double-stranded DNA. This contra-helicase activity is polar, i.e., the impedance to unwinding takes place in only one orientation of the .tau. sequence. The results illuminate the mechanism of replication termination specifically at .tau.