Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, Louisiana 70112, United States.
Department of Computer Science, Tulane University, 6823 St Charles Avenue, New Orleans, Louisiana 70118, United States.
Biochemistry. 2021 May 25;60(20):1578-1586. doi: 10.1021/acs.biochem.1c00095. Epub 2021 May 6.
Chicken ovalbumin (cOVA) has been studied for decades primarily due to the robust genetic and molecular resources that are available for experimental investigations. cOVA is a member of the serpin superfamily of proteins that function as protease inhibitors, although cOVA does not exhibit this activity. As a serpin, cOVA possesses a protease-sensitive reactive center loop that lies adjacent to the OVA 323-339 CD4+ T-cell epitope. We took advantage of the previously described single-substitution variant, OVA R339T, which can undergo the dramatic structural transition observed in serpins, to study how changes in loop size and protein stability influence the processing and presentation of the OVA 323-339 epitope. We observed that the OVA R339T loop insertion increases the stability and protease resistance, resulting in the reduced presentation of the OVA 323-339 epitope . These findings have implications for the design of more effective vaccines for the treatment of infectious diseases and cancer as well as the development of more robust CD4+ T-cell epitope prediction tools.
鸡卵清白蛋白 (cOVA) 已被研究了数十年，主要是因为其具有强大的遗传和分子资源，可用于实验研究。cOVA 是丝氨酸蛋白酶抑制剂超家族的一员，尽管 cOVA 不具有这种活性。作为丝氨酸蛋白酶抑制剂，cOVA 具有靠近 OVA 323-339 CD4+ T 细胞表位的蛋白酶敏感反应中心环。我们利用先前描述的单取代变体 OVA R339T，该变体可以经历丝氨酸蛋白酶抑制剂中观察到的剧烈结构转变，来研究环大小和蛋白质稳定性的变化如何影响 OVA 323-339 表位的加工和呈递。我们观察到 OVA R339T 环插入增加了稳定性和蛋白酶抗性，导致 OVA 323-339 表位的呈递减少。这些发现对于设计更有效的传染病和癌症治疗疫苗以及开发更强大的 CD4+ T 细胞表位预测工具具有重要意义。
