关键词: 施氏假单胞菌A1501, GlnK蛋白, &alpha, -酮戊二酸, 分子互作

Abstract: PⅡ protein is a general regulator of nitrogen metabolism in bacteria, which can sense the changes of carbon and nitrogen signals in cells and fine-tune the interaction between itself and the target proteins, so as to achieve the purpose of cascade regulation of nitrogen fixation. α-ketoglutarate is an important signal molecule of intracellular carbon status. Previous studies have found that PⅡ protein can bind α-ketoglutarate to sense intracellular carbon status, but there are differences in different bacteria. Pseudomonas stutzeri A1501 contains only one PⅡ protein GlnK, which plays an important role in the regulation of nitrogen fixation in A1501, but the specific carbon signal perception and transduction mechanisms needs to be further explored. Based on this, GlnK protein was expressed in Escherichia coli exogenously, and the in vitro interaction between GlnK protein and carbon signal molecule α-ketoglutarate was studied by microscale thermophoresis (MST) method. It was found that GlnK could interact with the signal molecule α-ketoglutarate in vitro, and it was further confirmed that the 89th glycine (G89, Gly89) of GlnK protein might be related to the interaction. The results laid a foundation for further analysis of α-ketoglutarate signal transduction in A1501, and also provided theoretical support for the in-depth analysis of the coupling mechanism of carbon and nitrogen metabolism of nitrogen-fixing bacteria.

Key words: Pseudomonas stutzeri A1501, GlnK protein, α-ketoglutarate, interaction