title: pH-dependent structures of an i-motif DNA in solution.
abstract: We have investigated for the first time the structure of i-motif DNA in solution at various pH conditions by using synchrotron small-angle X-ray scattering technique. To facilitate direct structural comparison between solution structures of i-motif DNA at various pH values, we created atomic coordinates of i-motif DNA from a fully folded to unfolded atomic model. Under mild acidic conditions, the conformations for i-motif DNA appeared to be similar to that of the partially unfolded i-motif atomic model in overall shape, rather than the fully folded i-motif atomic model. Collectively, our observations indicate that i-motif DNA molecule is structurally dynamic over a wide pH range, adopting multiple conformations ranging from the folded i-motif structure to a random coil conformation. As the i-motif structure has been used as an important component in nanomachines, we can therefore believe that the structural evidence presented herein will promote the development of future DNA-based molecular-actuator devices.
authors.affiliation: Department of Chemistry, National Research Laboratory for Polymer Synthesis and Physics, Pohang Accelerator Laboratory, Center for Electro-Photo Behaviors in Advanced Molecular Systems, Polymer Research Institute, Republic of Korea. sjk@hanyang.ac.kr
authors.forename: Kyeong Sik
authors.initials: KS
authors.lastname: Jin
authors.forename: Su Ryon
authors.initials: SR
authors.lastname: Shin
authors.forename: Byungcheol
authors.initials: B
authors.lastname: Ahn
authors.forename: Yecheol
authors.initials: Y
authors.lastname: Rho
authors.forename: Seon Jeong
authors.initials: SJ
authors.lastname: Kim
authors.forename: Moonhor
authors.initials: M
authors.lastname: Ree
mesh_terms: D004247:DNA / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D053838:Scattering, Small Angle; D012996:Solutions; D014961:X-Ray Diffraction
chemical_list: D012996:Solutions; D004247:DNA