DNA G-Wire Formation Using an Artificial Peptide is Controlled by Protease Activity

• Main Authors: Kenji Usui, Arisa Okada, Shungo Sakashita, Masayuki Shimooka, Takaaki Tsuruoka, Shu-ichi Nakano, Daisuke Miyoshi, Tsukasa Mashima, Masato Katahira, Yoshio Hamada
• Format: Article
• Language: English
• Published: MDPI AG 2017-11-01
• Series: Molecules
• Subjects: designed peptide; G-wire; G-quadruplex; protease; peptide nucleic acid; PNA
• Online Access: https://www.mdpi.com/1420-3049/22/11/1991

The development of a switching system for guanine nanowire (G-wire) formation by external signals is important for nanobiotechnological applications. Here, we demonstrate a DNA nanostructural switch (G-wire <--> particles) using a designed peptide and a protease. The peptide consists of a PNA sequence for inducing DNA to form DNA–PNA hybrid G-quadruplex structures, and a protease substrate sequence acting as a switching module that is dependent on the activity of a particular protease. Micro-scale analyses via TEM and AFM showed that G-rich DNA alone forms G-wires in the presence of Ca2+, and that the peptide disrupted this formation, resulting in the formation of particles. The addition of the protease and digestion of the peptide regenerated the G-wires. Macro-scale analyses by DLS, zeta potential, CD, and gel filtration were in agreement with the microscopic observations. These results imply that the secondary structure change (DNA G-quadruplex <--> DNA/PNA hybrid structure) induces a change in the well-formed nanostructure (G-wire <--> particles). Our findings demonstrate a control system for forming DNA G-wire structures dependent on protease activity using designed peptides. Such systems hold promise for regulating the formation of nanowire for various applications, including electronic circuits for use in nanobiotechnologies.