Institute of Microbiology Chinese Academy of Sciences, Beijing, China.
FEMS Microbiol Lett. 2013 Aug;345(2):141-6. doi: 10.1111/1574-6968.12197. Epub 2013 Jul 1.
The ice-nucleation protein (INP) from Pantoea ananatis was expressed in Escherichia coli. INP expression increased the freezing point of the E. coli culture by a few degrees. Deletion of FabH, an important enzyme in fatty acid biosynthesis, significantly inhibited the ice-nucleation activity. Increased unsaturated fatty acids in the fabH mutant cells decreased the ice-nucleation activity. Adding exogenous saturated fatty acids increased both E. coli fatty acid saturation and the ice-nucleation activity. In contrast, adding unsaturated fatty acids exhibited the opposite effects. Furthermore, an E. coli MG1655-fadR strain with high saturated fatty acids content was constructed, in which the INP activity was enhanced by about 17% compared with its activity in the wild-type MG1655 strain.
从 Pantoea ananatis 中表达的冰核蛋白（INP）在大肠杆菌中表达。INP 的表达将大肠杆菌培养物的冰点提高了几度。脂肪酸生物合成中重要酶 FabH 的缺失显著抑制了冰核活性。fabH 突变细胞中不饱和脂肪酸的增加降低了冰核活性。添加外源性饱和脂肪酸可同时增加大肠杆菌脂肪酸饱和度和冰核活性。相反，添加不饱和脂肪酸则表现出相反的效果。此外，构建了具有高饱和脂肪酸含量的大肠杆菌 MG1655-fadR 菌株，其中 INP 活性比野生型 MG1655 菌株提高了约 17%。
