Effects of G-Quadruplex Topology on Electronic Transfer Integrals.
G-quadruplex is a quadruple helical form of nucleic acids that can appear in guanine-rich parts of the genome. The basic unit is the G-tetrad, a planar assembly of four guanines connected by eight hydrogen bonds. Its rich topology and its possible relevance as a drug target for a number of diseases have stimulated several structural studies. The superior stiffness and electronic π-π overlap between consecutive G-tetrads suggest exploitation for nanotechnologies. Here we inspect the intimate link between the structure and the electronic properties, with focus on charge transfer parameters. We show that the electronic couplings between stacked G-tetrads strongly depend on the three-dimensional atomic structure. Furthermore, we reveal a remarkable correlation with the topology: a topology characterized by the absence ofsyn-antiG-G sequences can better support electronic charge transfer. On the other hand, there is no obvious correlation of the electronic coupling with usual descriptors of the helix shape. We establish a procedure to maximize the correlation with a global helix shape descriptor.
China Building Materials Academy, Beijing 100024, China. swm@mail.sdu.edu.cn.
Wenming
W
Sun
Center S3, CNR Institute of Nanoscience, Via Campi 213/A, Modena 41125, Italy. daniele.varsano@nano.cnr.it.
Daniele
D
Varsano
Center S3, CNR Institute of Nanoscience, Via Campi 213/A, Modena 41125, Italy. rosa.difelice@unimore.it.|Department of Physics and Astronomy, Universsity of Southern California, Los Angeles, CA 90089, USA. rosa.difelice@unimore.it.
Rosa
R
Di Felice
DNA; G-quadruplex; density functional theory; electronic coupling; structure; transfer integrals