Institute of Cell Biophysics, Russian Academy of Sciences, PSCBR RAS, Institutskaya, 3, Pushchino 142290, Russia.
Institute of Protein Research, Russian Academy of Sciences, Institutskaya, 4, Pushchino 142290, Russia.
Int J Mol Sci. 2022 Jul 29;23(15):8379. doi: 10.3390/ijms23158379.
ExuR and UxuR are paralogous proteins belonging to the GntR family of transcriptional regulators. Both are known to control hexuronic acid metabolism in a variety of Gammaproteobacteria but the relative impact of each of them is still unclear. Here, we apply 2D difference electrophoresis followed by mass-spectrometry to characterise the changes in the proteome in response to a or deletion. Our data clearly show that the effects are different: deletion of resulted in strongly enhanced expression of D-mannonate dehydratase UxuA and flagellar protein FliC, and in a reduced amount of outer membrane porin OmpF, while the absence of ExuR did not significantly alter the spectrum of detected proteins. Consequently, the physiological roles of proteins predicted as homologs seem to be far from identical. Effects of deletion were largely dependent on the cultivation conditions: during growth with glucose, UxuA and FliC were dramatically altered, while during growth with glucuronate, activation of both was not so prominent. During the growth with glucose, maximal activation was detected for FliC. This was further confirmed by expression analysis and physiological tests, thus suggesting the involvement of UxuR in the regulation of bacterial motility and biofilm formation.
ExuR 和 UxuR 是属于 GntR 家族转录调控因子的同工蛋白。两者都已知可控制多种γ变形菌中的己糖二酸代谢，但它们各自的相对影响仍不清楚。在这里，我们应用二维差异电泳结合质谱法来描述响应或缺失的蛋白质组变化。我们的数据清楚地表明，这些影响是不同的：缺失导致 D-甘露糖酸脱水酶 UxuA 和鞭毛蛋白 FliC 的表达显著增强，而外膜孔蛋白 OmpF 的含量减少，而 ExuR 的缺失则没有显著改变检测到的蛋白质谱。因此，预测为同源物的蛋白质的生理作用似乎远非相同。的缺失的影响在很大程度上取决于培养条件：在葡萄糖生长时，UxuA 和 FliC 发生了剧烈变化，而在葡糖醛酸生长时，两者的激活并不那么明显。在葡萄糖生长过程中，检测到 FliC 的最大激活。这通过表达分析和生理测试进一步得到证实，因此表明 UxuR 参与了细菌运动性和生物膜形成的调节。
