1. 毕业设计（论文）的内容和要求

论文内容 大肠杆菌是生产动物蛋白药物蛋白使用广泛的宿主，然而，在大肠杆菌通过细胞质表达生产含二硫键的真核短多肽是非常困难的，会被多种蛋白质降解的同时，很难在细胞质成正确的二硫键。

白介素21即白细胞介素-21，由活化的cd4 t细胞分泌，分子结构与il-15相似，参与调节b细胞增殖，协同il-15促进骨髓前体细胞增殖和nk细胞增殖、分化和细胞毒活性。

本课题致力于获得大量白介素，为其临床应用奠定基础。

2. 参考文献

[1] smith d b, johnson k s. single-step purification of polypeptides expressed in escherichia coli as fusions with glutathione s-transferase[j]. gene, 1988, 67: 31-40. [2] duplay p, hofnung m. two regions of mature periplasmic maltose-binding protein of escherichia coli involved in secretion[j]. journal of bacteriology, 1988, 170: 4445-4450. [3] wilkinson, d.l., harrison, r.g., 1991. predicting the solubility of recombinant proteins in escherichia coli. biotechnology (n. y.) 9, 443#8211;448. [4] bird l e. high throughput construction and small scale expression screening of multi-tag vectors in escherichia coli[j]. methods, 2011, 55: 29-37. [5] dummler a, lawrence a m, de marco a. simplified screening for the detection of soluble fusion constructs expressed in e. coli using a modular set of vectors[j]. microbial cell factories, 2005, 4: 34. [6] costa s j, almeida a, castro a, et al. the novel fh8 and h fusion partners for soluble protein expression in escherichia coli: a comparison with the traditional gene fusion technology[j]. applied microbiology and biotechnology, 2013, 97: 6779-6791. [7] young c l, britton z t, robinson a s. recombinant protein expression and purification: a comprehensive review of affinity tags and microbial applications[j]. biotechnol j, 2012, 7: 620-634. [8] song j a, lee d s, park j s, et al. the n‐domain of escherichia coli phosphoglycerate kinase is a novel fusion partner to express aggregation‐prone heterologous proteins[j]. biotechnology and bioengineering, 2012, 109: 325-335. [9] santner a a, croy c h, vasanwala f h, et al. sweeping away protein aggregation with entropic bristles: intrinsically disordered protein fusions enhance soluble expression[j]. biochemistry, 2012, 51: 7250-7262. [10] costa s j m d. development of a novel fusion system for recombinant protein production and purification in escherichia coli[j]. 2013. [11] ohana r f, encell l p, zhao k, et al. halotag7: a genetically engineered tag that enhances bacterial expression of soluble proteins and improves protein purification[j]. protein expr purif, 2009, 68: 110-120. [12] cheng y, gu j, wang h-g, et al. espa is a novel fusion partner for expression of foreign proteins in escherichia coli[j]. journal of biotechnology, 2010, 150: 380-388. [13] 王彤，张娟*，厉道娟，罗晨，吴沁航，高美风，王旻。

重组人白介素 21 的原核表达与体外活性研究的优化。

药物生物技术 pharmaceutical biotechnology 2013，20(4) : 283 ～ 28 [14] 李振国 ,徐明波 ,牛罡 ,陈遥 ,姚文兵在大肠杆菌周质表达重组蛋白的研究进展。

3. 毕业设计（论文）进程安排

起讫日期 设计（论文）各阶段工作内容 备 注 2017.2.26-2017.3.2 初步实验，考察初步结果 2017.3.3-2017.3.9 查阅文献，设计实验方案 2017.3.10-2017.5.4 完善实验方案，系统地进行实验 2017.5.5-2017.5.31 整理实验数据，总结实验结果 2017.6.1-2017.6.15 撰写毕业论文