Shultzaberger R K, Schneider T D
Catoctin High School, 14745 Sabillasville Road, Thurmont, MD 21788, USA.
Nucleic Acids Res. 1999 Feb 1;27(3):882-7. doi: 10.1093/nar/27.3.882.
In vitro experiments that characterize DNA-protein interactions by artificial selection, such as SELEX,are often performed with the assumption that the experimental conditions are equivalent to natural ones. To test whether SELEX gives natural results, we compared sequence logos composed from naturally occurring leucine-responsive regulatory protein (Lrp) binding sites with those composed from SELEX-generated binding sites. The sequence logos were significantly different, indicating that the binding conditions are disparate. A likely explanation is that the SELEX experiment selected for a dimeric or trimeric Lrp complex bound to DNA. In contrast, natural sites appear to be bound by a monomer. This discrepancy suggests that in vitro selections do not necessarily give binding site sets comparable with the natural binding sites.
通过人工筛选（如SELEX）来表征DNA-蛋白质相互作用的体外实验，通常是在实验条件等同于自然条件的假设下进行的。为了测试SELEX是否能得出自然结果，我们将由天然存在的亮氨酸响应调节蛋白（Lrp）结合位点组成的序列标识与由SELEX产生的结合位点组成的序列标识进行了比较。这些序列标识有显著差异，表明结合条件不同。一个可能的解释是，SELEX实验选择的是与DNA结合的二聚体或三聚体Lrp复合物。相比之下，天然位点似乎是由单体结合的。这种差异表明，体外筛选不一定能得到与天然结合位点相当的结合位点集。
