title: Porphyrin intercalation in G4-DNA quadruplexes by molecular dynamics simulations.
abstract: We investigated the intercalation of a porphyrin derivative (TMPyP) between guanine tetrads (G4-tetrads, G4t's) in 4-stranded G4-DNA oligomers by classical molecular dynamics simulations. Contrary to experimental evidence on very short oligomers that contain stabilizing cations, we find that TMPyP can stack with the G4-tetrads in the absence of interplane cations. A high TMPyP/G4t stoichiometric ratio of 1/2 induces strong deformations of the G4-quadruplexes. A lower ratio of 1/8 is better compatible with the helical conformation. When a TMPyP is accommodated between two tetrads, the stacking distance between the intercalated molecule and a G4-tetrad is approximately 4.3-4.7 A. We find that the possibility of regular TMPyP intercalation depends on the length of the quadruplex, on the stoichiometric ratio and on the edge termination motif.
authors.affiliation: INFM-CNR National Center on nanoStructures and bioSystems at Surfaces (S3), I-41100 Modena, Italy.
authors.forename: Manuela
authors.initials: M
authors.lastname: Cavallari
authors.forename: Anna
authors.initials: A
authors.lastname: Garbesi
authors.forename: Rosa
authors.initials: R
authors.lastname: Di Felice
mesh_terms: D003198:Computer Simulation; D054856:G-Quadruplexes; D006860:Hydrogen Bonding; D008958:Models, Molecular; D015394:Molecular Structure; D009690:Nucleic Acid Conformation; D011166:Porphyrins / Q000737:chemistry*
chemical_list: D011166:Porphyrins; C021096:tetra(4-N-methylpyridyl)porphine