SPECIFICITY OF DNA RECOGNITION IN THE NUCLEOPROTEIN COMPLEX FOR SITE-SPECIFIC RECOMBINATION BY TN21 RESOLVASE
SPECIFICITY OF DNA RECOGNITION IN THE NUCLEOPROTEIN COMPLEX FOR SITE-SPECIFIC RECOMBINATION BY TN21 RESOLVASE
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DOI：
10.1093/nar/21.24.5712
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发表时间：
1993-12-11
影响因子：
14.9
通讯作者：
HALFORD, SE
中科院分区：
文献类型：
--
作者：
HALL, SC;HALFORD, SE
来自Tn 3样转座子的解旋酶催化res位点处的位点特异性重组。每个res位点有3个解离酶结合位点，I、II和III。Tn 3和Tn 21中的res位点在I和II处具有相似的结构，但在III处不同。Tn 21 res位点的突变表明，子位点III是重组所必需的，尽管由Tn 21解离酶识别的III中的序列与Tn 3位点中的等同序列定位不同。III的缺失导致重组率下降1,000倍。但是III位的其他突变，改变了3或4个连续的碱基对，即使突变是在这种螺旋-转角-螺旋蛋白的靶序列中，也只会导致速率降低1.5至4倍。Tn 21解离酶在许多不同的DNA序列上具有相似活性的原因可能是由于其重组复合物中蛋白质-蛋白质和蛋白质-DNA相互作用的多样性。这种缺乏精确性可能是核蛋白复合物的一般特征。
Resolvases from Tn3-like transposons catalyse site-specific recombination at res sites. Each res site has 3 binding sites for resolvase, I, II, and III. The res sites in Tn3 and Tn21 have similar structures at I and II but they differ at III. Mutagenesis of the Tn21 res site showed that sub-site III is essential for recombination though the sequences in III that are recognized by Tn21 resolvase are positioned differently from the equivalent sequences in the Tn3 site. The deletion of III caused a 1,000-fold drop in the rate of recombination. But other mutations at III, changing 3 or 4 consecutive base pairs, caused only 1.5- to 4-fold decreases in rate, even when the mutations were in target sequences for this helix-turn-helix protein. The reason why Tn21 resolvase has similar activities at a number of different DNA sequences may be due to the multiplicity of protein-protein and protein-DNA interactions in its recombinogenic complex. This lack of precision may be a general feature of nucleoprotein complexes.