Abstract: Objective: To design a self-assembling peptide K2I4K2 as a new type of surfactant to stabilize Taq DNA polymerase, to explore the half-life of Taq DNA polymerase at high temperature and the influence on PCR amplification efficiency. Methods: Circular dichroism spectrum was used to detect the secondary structure of short peptide K2I4K2 in different physical and chemical condition. Atomic force microscope was used to detect the nanostructure characteristics formed by K2I4K2. UV-vis spectrum was used to examine the impact on the half-life of Taq enzyme stabilized by K2I4K2 at high temperature. Ordinary PCR was used to verify the feasibility of the application of K2I4K2 in the PCR. RT-qPCR was used to detecte of K2I4K2’s effect on the amplification efficiency of Taq polymerase. Results: Peptide K2I4K2 can form nanofiber structure in salt solution, and owns stable secondary structure at high temperature. UV-vis spectrum result indicated that peptide K2I4K2 increases the half-life by 1.6-fold compared with the stability in buffer alone. Furthermore, RT-qPCR indicated that peptide K2I4K2 greatly increase the amplification efficiency of Taq polymerase. Conclusion: Peptide K2I4K2 more significantly increased the thermal stability of the Taq DNA polymerase at a high temperature, and can be well used in the PCR system.

Key words: self-assembling peptide, nanofiber, half-life of Taq DNA polymerase, amplification of PCR