DelProposto James, Majmudar Chinmay Y, Smith Janet L, Brown William Clay
High-throughput Protein Lab, Center for Structural Biology, Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, Michigan 48109, USA.
Protein Expr Purif. 2009 Jan;63(1):40-9. doi: 10.1016/j.pep.2008.08.011. Epub 2008 Sep 12.
A persistent problem in heterologous protein production is insolubility of the target protein when expressed to high level in the host cell. A widely employed strategy for overcoming this problem is the use of fusion tags. The best fusion tags promote solubility, may function as purification handles and either do not interfere with downstream applications or may be removed from the passenger protein preparation. A novel fusion tag is identified that meets these criteria. This fusion tag is a monomeric mutant of the Ocr protein (0.3 gene product) of bacteriophage T7. This fusion tag displays solubilizing activity with a variety of different passenger proteins. We show that it may be used as a purification handle similar to other fusion tags. Its small size and compact structure are compatible with its use in downstream applications of the passenger protein or it may be removed and purified away from the passenger protein. The use of monomeric Ocr (Mocr) as a complement to other fusion tags such as maltose-binding protein will provide greater flexibility in protein production and processing for a wide variety of protein applications.
在异源蛋白质生产中，一个长期存在的问题是目标蛋白在宿主细胞中高水平表达时会出现不溶性。克服这一问题的一种广泛采用的策略是使用融合标签。最佳的融合标签可促进溶解性，可作为纯化工具，并且既不干扰下游应用，也可从目的蛋白制剂中去除。已鉴定出一种符合这些标准的新型融合标签。这种融合标签是噬菌体T7的Ocr蛋白（0.3基因产物）的单体突变体。这种融合标签对多种不同的目的蛋白都具有增溶活性。我们表明它可以用作与其他融合标签类似的纯化工具。它的小尺寸和紧凑结构使其适用于目的蛋白的下游应用，或者可以从目的蛋白中去除并纯化。使用单体Ocr（Mocr）作为麦芽糖结合蛋白等其他融合标签的补充，将为各种蛋白质应用在蛋白质生产和加工方面提供更大的灵活性。
