Cock Peter J A, Whitworth David E
Mol Biol Evol. 2007 Nov;24(11):2355-7. doi: 10.1093/molbev/msm170. Epub 2007 Aug 19.
Two-component systems (TCSs) are common signal transduction systems, typically comprising paired histidine protein kinase (HK) and response regulator (RR) proteins. In many examples, it appears RR and HK genes have fused, producing a "hybrid kinase " We have characterized a set of prokaryotic genes encoding RRs, HKs, and hybrid kinases, enabling characterization of gene fusion and fission. Primary factors correlating with fusion rates are the presence of transmembrane helices in HKs and the presence of DNA-binding domains in RRs, features that require correct (and separate) spatial location. In the absence of such features, there is a relative abundance of fused genes. The order of paired HK and RR genes and the nucleotide distance between encoded domains also correlate with apparent gene fusion rates. We propose that localization requirements and relative positioning of encoded domains within TCS genes affect the function (and therefore retention) of hybrid kinases resulting from gene fusion.
双组分系统（TCSs）是常见的信号转导系统，通常由配对的组氨酸蛋白激酶（HK）和反应调节蛋白（RR）组成。在许多实例中，RR和HK基因似乎发生了融合，产生了一种“杂合激酶”。我们已经对一组编码RR、HK和杂合激酶的原核基因进行了表征，从而能够对基因融合和裂变进行表征。与融合率相关的主要因素是HK中跨膜螺旋的存在以及RR中DNA结合结构域的存在，这些特征需要正确（且分开）的空间定位。在没有这些特征的情况下，融合基因相对丰富。配对的HK和RR基因顺序以及编码结构域之间的核苷酸距离也与明显的基因融合率相关。我们提出TCS基因内编码结构域的定位要求和相对位置会影响基因融合产生的杂合激酶的功能（进而影响其保留情况）。
