Emulating Titin by a Multidomain DNA Structure

Titin, a giant protein containing multiple tandem domains, is essential in maintaining the superior mechanical performance of muscle. The consecutive and reversible unfolding and refolding of the domains are crucial for titin to serve as a modular spring. Since the discovery of the mechanical features of a single titin molecule, the exploration of biomimetic materials with titin-emulating modular structures has been an active field. However, it remains a challenge to prepare these modular polymers on a large scale due to the complex synthesis process. In this study, we propose modular DNA with multiple hairpins (MH-DNA) as the fundamental block for the bottomup design of advanced materials. By analyzing the unfolding and refolding dynamics of modular hairpins by atomic force microscopy (AFM)-based single-molecule force spectroscopy (SMFS), we find that MH-DNA shows comparable stability to those of polyproteins like titin. The unique low hysteresis of modular hairpin makes it an ideal molecular spring with remarkable mechanical efficiency. On the basis of the well-established DNA synthesis techniques, we anticipate that MH-DNA can be used as a promising building block for advanced materials with a combination of superior structural stability, considerable extensibility, and high mechanical efficiency.

Automated summary

Titin, a giant protein, plays a vital role in muscle's superior mechanical performance. The unfolding and refolding of its tandem domains are crucial for its modular spring function. This study proposes the use of modular DNA with multiple hairpins (MH-DNA) as a fundamental block for designing advanced materials. The analysis using atomic force microscopy (AFM)-based single-molecule force spectroscopy (SMFS) shows that MH-DNA exhibits similar stability to polyproteins like titin, making it an ideal molecular spring with exceptional mechanical efficiency.