title: The effects of molecular crowding on the structure and stability of g-quadruplexes with an abasic site.
abstract: Both cellular environmental factors and chemical modifications critically affect the properties of nucleic acids. However, the structure and stability of DNA containing abasic sites under cell-mimicking molecular crowding conditions remain unclear. Here, we investigated the molecular crowding effects on the structure and stability of the G-quadruplexes including a single abasic site. Structural analysis by circular dichroism showed that molecular crowding by PEG200 did not affect the topology of the G-quadruplex structure with or without an abasic site. Thermodynamic analysis further demonstrated that the degree of stabilization of the G-quadruplex by molecular crowding decreased with substitution of an abasic site for a single guanine. Notably, we found that the molecular crowding effects on the enthalpy change for G-quadruplex formation had a linear relationship with the abasic site effects depending on its position. These results are useful for predicting the structure and stability of G-quadruplexes with abasic sites in the cell-mimicking conditions.
authors.affiliation: Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, 7-1-20 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Fujimoto
authors.forename: Shu-Ichi
authors.initials: S
authors.lastname: Nakano
authors.forename: Daisuke
authors.initials: D
authors.lastname: Miyoshi
authors.forename: Naoki
authors.initials: N
authors.lastname: Sugimoto