The toxicity of Vip3Aa protein on insect pests is known, however, it remains unclear underlying the structure-dependent molecular function of the Vip3Aa protein. To investigate the novel function of the Vip3Aa protein, we isolated recombinant Vip3Aa protein. The recombinant Vip3Aa protein was mostly present as oligomeric form depending on the hydrophobic amino acid residue. We found that the oligomeric Vip3Aa protein specifically binds to nucleic acids, including single-stranded (ssDNA) and double-stranded DNA (dsDNA). The conformational and functional domains of the Vip3Aa protein were confirmed by separating the Vip3Aa full and Vip3Aa active (actVip3Aa) forms using size exclusion chromatography and nucleic acid binding activity. Interestingly, actVip3Aa protein had a conformational change and decreased DNA binding activity compared to that of the Vip3Aa full, suggesting that N-terminal part of the Vip3Aa play an important role in maintaining the conformation and nucleic acid binding activity. These studies highlight novel functional characterization of the insecticidal protein Vip3Aa on DNA binding activity and may be attributed to the protection of DNA from the damage caused by oxidative stress.

Vip3Aa蛋白对害虫的毒性是已知的，但仍不清楚Vip3Aa蛋白的结构依赖性分子功能。为了研究Vip3Aa蛋白的新功能，我们分离了重组Vip3Aa蛋白。重组Vip3Aa蛋白主要以寡聚形式存在，具体取决于疏水氨基酸残基。我们发现寡聚的Vip3Aa蛋白特异性结合核酸，包括单链（ssDNA）和双链DNA（dsDNA）。通过使用尺寸排阻色谱法和核酸结合活性分离Vip3Aa完整形式和Vip3Aa活性形式（actVip3Aa）形式，确认了Vip3Aa蛋白的构象和功能域。有趣的是，与完整的Vip3Aa相比，actVip3Aa蛋白具有构象变化并降低了DNA结合活性，这表明Vip3Aa的N端部分在维持构象和核酸结合活性方面起着重要作用。