Gleiter S, Lilie H
Martin-Luther-Universität Halle, Institut für Biotechnologie, D-06120 Halle, Germany.
Protein Sci. 2001 Feb;10(2):434-44. doi: 10.1110/ps.31101.
Therapeutic application of virus-based delivery systems often implies a change of the tropism of these vectors. This can be achieved by insertion of polypeptides (e.g., antibody fragments) in viral coat proteins. Such fusion proteins have only been used in viral vectors so far and, as part of a virus, they have not been available for a detailed biophysical characterization. We analyzed a fusion protein called VP1-Z, which is based on the polyoma virus coat protein VP1 and protein Z. Protein Z is an engineered antibody-binding domain derived from protein A from Staphylococcus aureus. The fusion VP1-Z was constructed by insertion of protein Z in the HI-loop of VP1. As wild-type VP1, VP1-Z formed pentameric capsomers and assembled to VLPs in vitro. The stability of these particles was very similar compared to that of VLPs of wild-type VP1. Protein Z was fully structured in the fusion protein and was still capable of binding antibodies on the surface of VLPs of VP1-Z. Using this fusion protein, we could change the tropism of polyoma VLPs toward cells presenting on their surface the antigen of the coupled antibody.
基于病毒的递送系统的治疗应用通常意味着这些载体的嗜性发生改变。这可以通过在病毒衣壳蛋白中插入多肽（例如抗体片段）来实现。到目前为止，这种融合蛋白仅用于病毒载体，并且作为病毒的一部分，它们尚未用于详细的生物物理表征。我们分析了一种名为VP1-Z的融合蛋白，它基于多瘤病毒衣壳蛋白VP1和蛋白Z。蛋白Z是一种源自金黄色葡萄球菌蛋白A的工程化抗体结合结构域。通过将蛋白Z插入VP1的HI环中构建融合蛋白VP1-Z。与野生型VP1一样，VP1-Z形成五聚体衣壳粒并在体外组装成病毒样颗粒。与野生型VP1的病毒样颗粒相比，这些颗粒的稳定性非常相似。蛋白Z在融合蛋白中完全结构化，并且仍然能够结合VP1-Z病毒样颗粒表面的抗体。使用这种融合蛋白，我们可以将多瘤病毒样颗粒的嗜性改变为朝向在其表面呈现偶联抗体抗原的细胞。
