集胞藻酰基载体蛋白基因过量表达对脂肪酸合成的影响

酰基载体蛋白(ACP)是微生物脂肪酸生物合成途径中的一个关键蛋白。为了促进集胞藻脂肪酸的积累,以集胞藻PCC6803为研究对象,成功构建了用于过量表达ACP(ssl2084)基因的同源重组质粒ssl2084⁽(+))并在集胞藻PCC6803中进行转化。将ssl2084⁽(+))突变株进行DNA水平和蛋白质水平鉴定,结果表明,ssl2084基因已经得到过量表达。利用气相色谱—质谱联用技术(GC-MS)对突变藻株在不同温度下脂肪酸的含量及组分进行检测,发现在30℃培养条件下ssl2084⁽(+))突变株中C12:0、C16:0和C18:0的含量显著增加,分别为1.50、8.74和0.60 mg·g^-1,与野生型相比分别增加了54.71%、50.82%和155.86%;在20℃低温胁迫培养条件下,C12:0、C16:0和C18:0的含量分别达到1.70、11.85和2.31 mg·g^-1,与野生型相比分别增加了31.94%、47.35%和39.90%。以上结果表明,在集胞藻PCC68...

Effects of overexpression of acyl carrier protein gene in Synechocystis on fatty acids synthesis

Acyl carrier protein (ACP) is a key protein in fatty acid biosynthesis pathway of microorganisms. In order to promote the accumulation of fatty acids in Synechocystis, the homologous recombinant plasmid ssl2084⁽⁺⁾ was successfully constructed for overexpressing the ACP (ssl2084) gene and transformed into wild-type Synechocystis sp. PCC6803. Identification of the ssl2084⁽⁺⁾ mutant strain at the DNA and protein levels showed that the ssl2084 gene had been overexpressed. The content and composition of the fatty acids in the mutant strain under different temperatures were detected by liquid chromatography-mass spectrometry (GC-MS). The results showed that the contents of C12:0, C16:0 and C18:0 in ssl2084⁽⁺⁾ mutant at 30 ℃ were 1.50, 8.74 and 0.60 mg·g^-1, respectively, which increased by 54.71%, 50.82% and 155.86%, respectively, compared with the wild type. Under the condition of low temperature stress culture at 20 ℃, the contents of C12:0, C16:0 and C18:0 reached 1.70, 11.85 and 2.31 mg·g^-1, respectively, which increased by 31.94%, 47.35% and 39.90%, respectively, compared with the wild type. The above results indicated that overexpression of ssl2084 gene in Synechocystis sp. PCC6803 could increase the content of medium and long chain fatty acids, and the low temperature condition could further increase the content of medium and long chain fatty acids.