Exonuclease VIII of Escherichia coli. II. Mechanism of action.
Exonuclease VIII of Escherichia coli. II. Mechanism of action.
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DOI：
10.1016/s0021-9258(17)44473-5
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发表时间：
1983-09
期刊：
影响因子：
--
通讯作者：
J. Joseph;R. Kolodner
中科院分区：
文献类型：
--
作者：
J. Joseph;R. Kolodner
来自大肠杆菌的外切核酸酶VIII显示优先降解线性双链体DNA，尽管检测到与单链线性DNA底物的有限量的活性。用含有单链断裂或缺口的双链环状底物未观察到溶核活性。外切核酸酶VIII显示从分子的5'末端降解线性双链体DNA，并通过进行性反应机制在5'至3'方向上进行。起始可以从5 '-羟基或5'-磷酸残基以相等的速率发生。线性双链DNA的降解产物是等量的5 ′-单核苷酸和单链DNA。外切核酸酶VIII在基因重组中可能发挥的作用进行了讨论。
Exonuclease VIII from Escherichia coli was shown to preferentially degrade linear duplex DNA, although a limited amount of activity with single-stranded linear DNA substrates was detected. No nucleolytic activity was observed with double-stranded circular substrates containing single strand breaks or gaps. Exonuclease VIII was shown to degrade linear duplex DNA from the 5' termini of the molecules and proceed in the 5' to 3' direction via a processive reaction mechanism. Initiation could occur from either a 5'-hydroxyl or 5'-phosphate residue at equal rates. The products of degradation of linear duplex DNA were an equivalent amount of 5'-mononucleotides and single-stranded DNA. Possible roles for exonuclease VIII in genetic recombination are discussed.