刘婧, 王杰, 华子春. Annexin A4-EGFP融合蛋白的表达纯化及其凋亡检测能力初探J. 药学学报, 2017,52(6): 904-910. doi: 10.16438/j.0513-4870.2017-0340
引用本文: 刘婧, 王杰, 华子春. Annexin A4-EGFP融合蛋白的表达纯化及其凋亡检测能力初探J. 药学学报, 2017,52(6): 904-910. doi: 10.16438/j.0513-4870.2017-0340
LIU Jing, WANG Jie, HUA Zi-chun. Expression, purification of annexin A4-EGFP fusion protein and preliminary study on its apoptosis detection abilityJ. Acta Pharmaceutica Sinica, 2017,52(6): 904-910. doi: 10.16438/j.0513-4870.2017-0340
Citation: LIU Jing, WANG Jie, HUA Zi-chun. Expression, purification of annexin A4-EGFP fusion protein and preliminary study on its apoptosis detection abilityJ. Acta Pharmaceutica Sinica, 2017,52(6): 904-910. doi: 10.16438/j.0513-4870.2017-0340

Annexin A4-EGFP融合蛋白的表达纯化及其凋亡检测能力初探

Expression, purification of annexin A4-EGFP fusion protein and preliminary study on its apoptosis detection ability

  • 摘要: 膜联蛋白(annexin)是一类进化保守的多基因家族蛋白,可与细胞膜磷脂酰丝氨酸(phosphatidyl­;serine,PS)结合,由于PS与许多重要疾病密切相关,具有作为药物发现新靶点的潜力,使得annexin具有良好 的药物发现价值和新药研发前景。Annexin A4(以下称A4)是膜联蛋白家族成员之一,参与多项细胞功能,如胞吐作用和凝血反应,所有这些功能与膜联蛋白可结合酸性磷脂的能力相关。目前对A4的功能尚不完全了解,获得足量的A4是深入了解A4的结构与功能的基础。为了克服传统从生物组织中提纯人源A4的方法得率不高,且较为复杂等问题,本文通过原核系统重组表达A4,以获取大量可溶性蛋白,探究其与PS的结合能力,为后续研究奠定基础。利用分子生物学的手段构建融合表达质粒pET28a-annexin A4-EGFP,大量表达、选用并比较了两种获取可溶性annexin A4-EGFP(以下称A4-EGFP)融合蛋白的纯化方法,同时检测A4-EGFP对凋亡细胞的识别能力。通过亲和层析纯化获得纯度为80% 的A4-EGFP;而选用膜吸附纯化方式,最终获得了纯度达90% 的 蛋白。流式细胞仪检测结果显示:A4-EGFP融合蛋白可识别和标记早期凋亡细胞,其与PS亲和力为79.58±11.68 nmol·L-1,与A5-EGFP和PS的亲和力同处一个数量级。本文成功实现了A4-EGFP在原核体系中的高效可溶性表达,建立了简易、高效的分离纯化方法,获得了产率高达75.2 mg·L-1的A4-EGFP,为深入研究A4的功能及其潜在的应用奠定了基础。

     

    Abstract: Annexin is a protein of evolutionarily conserved polygene family that binds to cell membrane phosphatidylserine (PS). PS is closely related to many diseases with a potential as a new drug target. Annexin has a good value in drug discovery and new drug development. Annexin A4 is a member of the annexins family. Annexin A4 involves in a number of cellular functions, such as exocytosis and coagulation. These functions are related to binding of annexin to acidic phospholipids. However, the detail function(s) of annexin A4 has not been fully uncovered. Production of annexin A4 in large quantity is prerequisite for indepth investigation of the structure-function relationship of annexin A4. Human annexin A4 was originally purified from the natural resource at a low yield due to the complex procedure. In the present study, annexin A4 was expressed in a prokaryotic system with a high yield of soluble protein. The plasmid pET28a-annexin A4-EGFP was constructed for the expression. Recombinant annexin A4-EGFP was purified using two methods. Affinity chromatography approach gave a protein yield at purity of 80%. While, the membrane absorption method produced the protein with the purity over 90%. Flow cytometric analysis showed that the annexin A4-EGFP fusion protein could recognize and bind to the apoptotic cells with an affinity PS at 79.58±11.68 nmol·L-1, which is at the same order of magnitude as A5-EGFP. We successfully achieved the efficient expression of annexin A4-EGFP in prokaryotic system, and provided an easy and convenient method for purifying a large amount of annexin A4-EGFP with a high purity. This study has laid a solid foundation for our study of the function of annexin A4 in the future.

     

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