Lambda integrase cleaves DNA in cis.
Lambda integrase cleaves DNA in cis.
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Lambda 整合酶以顺式方式切割 DNA。
DOI：
10.1002/j.1460-2075.1994.tb06762.x
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Landy,A
中科院分区：
文献类型：
--
作者：
Nunes-Düby,SE;Tirumalai,RS;Dorgai,L;Yagil,E;Weisberg,RA;Landy,A
在Int位点特异性重组酶家族中，DNA的切割是通过特定酪氨酸残基对激活的剪切型磷酸二酯键进行亲核攻击来完成的。有人提出，这种酪氨酸是由与被切割位点(反式切割)以外的位点结合的原基贡献的。为了验证这一假设，利用噬菌体Lambda和HK022的紧密相关整合酶(Ints)之间的DNA结合特异性的差异，将野生型Ints和切割或激活缺陷突变体定向到双特异性底物上的特定位置。对单个位点的Int裂解分析强烈表明，DNA裂解是由与裂解位点结合的Int催化的(顺式裂解)。这一结论与之前对Int家族的两个成员FLP和Lambda Int的实验结果形成了对比，后者支持反式切割假说。我们建议解释这种差异，并讨论这一令人惊讶的发现的含义，即Int家族重组酶似乎能够同时具有顺式和反式DNA切割机制。
In the Int family of site‐specific recombinases, DNA cleavage is accomplished by nucleophilic attack on the activated scissile phosphodiester bond by a specific tyrosine residue. It has been proposed that this tyrosine is contributed by a protomer bound to a site other than the one being cleaved (‘trans’ cleavage). To test this hypothesis, the difference in DNA binding specificity between closely related integrases (Ints) from phages lambda and HK022 was exploited to direct wild type Ints and cleavage‐ or activation‐defective mutants to particular sites on bispecific substrates. Analysis of Int cleavage at individual sites strongly indicates that DNA cleavage is catalyzed by the Int bound to the cleaved site (‘cis’ cleavage). This conclusion contrasts with those from previous experiments with two members of the Int family, FLP and lambda Int, that supported the hypothesis of trans cleavage. We suggest explanations for this difference and discuss the implications of the surprising finding that Int‐family recombinases appear capable of both cis and trans mechanisms of DNA cleavage.