Moderately thermostable phage Φ11 Cro repressor has novel DNA-binding capacity and physicochemical properties
Moderately thermostable phage Φ11 Cro repressor has novel DNA-binding capacity and physicochemical properties
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DOI：
10.5483/bmbrep.2009.42.3.160
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发表时间：
2009-03-31
期刊：
影响因子：
3.8
通讯作者：
Sau, Subrata
中科院分区：
文献类型：
--
作者：
Das, Malabika;Ganguly, Tridib;Sau, Subrata
温和金黄色葡萄球菌噬菌体Phi 11具有与类葡萄球菌相似的cl和cro阻遏基因。使用极纯的Phi 11 Cro（Phi 11 cro基因的产物），我们证明了这种蛋白质具有单结构域结构，在微摩尔浓度下在溶液中形成二聚体，即使在450 ℃下也保持了大部分的α螺旋结构。Phi 11 Cro在55-75 ℃的温度范围内对嗜热菌蛋白酶敏感，并在接近630 ℃的温度下开始聚集，这表明该蛋白质具有中等的热稳定性。在Phi 11 cl-cro基因间区域的三个同源15-bp操纵子（O 1、O2和O3）中，Phi 11 Cro仅有效地结合位于cl基因上游的O3。我们的比较分析表明，DNA结合能力，二级结构和二聚化效率的热稳定Phi 11 Cro是不同的P22 Cro和λ Cro，最好的表征代表的两个结构不同的Cro家族。[BMB报告2009; 42（3）：160-165]
The temperate Staphylococcus aureus phage Phi 11 harbors cl and cro repressor genes similar to those of lambdoid phages. Using extremely pure Phi 11 Cro (the product of the Phi 11 cro gene) we demonstrated that this protein possesses a single domain structure, forms dimers in solution at micromolar concentrations and maintains a largely alpha-helical structure even at 450 degrees C. Phi 11 Cro was sensitive to thermolysin at temperatures ranging from 55-75 degrees C and began to aggregate at similar to 630 degrees C, suggesting that the protein is moderately thermostable. Of the three homologous 15-bp operators (O1, O2, and O3) in the Phi 11 cl-cro intergenic region, Phi 11 Cro only binds efficiently to O3, which is located upstream of the cl gene. Our comparative analyses indicate that the DNA binding capacity, secondary structure and dimerization efficiency of thermostable Phi 11 Cro are distinct from those of P22 Cro and lambda Cro, the best characterized representatives of the two structurally different Cro families. [BMB reports 2009; 42(3): 160-165]