琥珀酰化修饰对甘油醛-3-磷酸脱氢酶活性的影响

通过定点突变和生物学分析，研究了赖氨酸琥珀酰化对GAPDH活性的影响。结果表明：发菜GAPDH基因全长为1 014 bp,由338个氨基酸组成，其中K264位点在藻类中高度保守。将K264位点的氨基酸K(AAA)突变为R(AGA),野生型和突变型GAPDH在大肠杆菌中表达，获得一个36.61 ku的外源蛋白。纯化后蛋白活性测定发现，发生琥珀酰化修饰比未发生琥珀酰化修饰的GAPDH(K264)活性显著降低，表明琥珀酰化修饰参与发菜GAPDH活性的调节。研究结果为深入研究发菜GAPDH的分子信息和生物学功能提供理论参考。

Effect of Succinylation Modification on Activity of Glyceraldehyde-3-phosphate Dehydrogenase

Lysine succinylation,a reversible and widely distributed post-translational modification,is known to play a regulatory role in both eukaryotes and prokaryotes.Our previous study found significant succinylation of GAPDH in Nostoc flagelliforme under drought stress,however,the effect of succinylated modification on GAPDH enzyme activity remains unclear.In this study,we investigated the influence of lysine succinylation on GAPDH activity by site-directed mutagenesis and biological analysis.The results showed that the GAPDH gene of N.flagelliforme was 1 014 bp in length and consisted of 338 amino acids,of which K264 was highly conserved in algae.The amino acid sequence AAA at K264 site was mutated into R (AGA),and wild type and mutant GAPDH of N.flagelliforme were expressed in E.coli to obtain a 36.61 ku foreign protein.The activity of GAPDH (K264) with succinylation modification after purification was significantly lower than that of GAPDH without the modification,indicating that succinylation modification was involved in the regulation of GAPDH activity in N.flagelliforme.These results confirm that the succinylation modification of GAPDH is an regulation mechanism in response to drought stress of N.flagelliforme,which provide a theoretical basis for further research on the molecular information and biological functions of GAPDH in N.flagelliforme.