Mosaic Evolution of Beta-Barrel-Porin-Encoding Genes in <i>Escherichia coli</i>
Xiongbin Chen, Xuxia Cai, Zewei Chen, Jinjin Wu, Gaofeng Hao, Quan Xiang Luo, Shuhong Liu, Junya Zhang, Yueming Hu, Guoqiang Zhu, Wolfgang Koester, Aaron P. White, Yi Cai, Yejun Wang
Abstract
Microevolution studies can disclose more elaborate evolutionary mechanisms of genes, appearing especially important for genes with multifaceted function such as those encoding outer membrane proteins. However, in most cases, the gene is considered as a whole unit, and the evolutionary patterns are disclosed. Here, we report that multiple bacterial porin proteins follow mosaic evolution, with local ingenic recombination combined with spontaneous mutations based on positive Darwinian selection, and conservation for most structural regions. This could represent a common mechanism for bacterial outer membrane proteins. The variable regions within each porin family showed large coincidence with the binding sites of bacteriophages, antibiotics, and immune factors and therefore would represent effective targets for the development of new antibacterial agents or vaccines.