Quantum Mechanical Simulation of the Interaction Between the Radioprotector cysteamine and DNA

Abstract

Interaction between DNA and aminothiol radioprotectors has been proved to be purely peripheral, i.e., it does not affect the bases but solely the sugar-phosphate backbone. (This interaction is essentially electrostatic, between the phosphate sites and the radioprotector cationic groups.)In order to progress in the understanding of the conformational aspects of this interaction, we have carried out a quantum mechanical simulation of the approach by a cysteamine molecule of the DNA backbone.Major conclusions drawn from this study are: ( I ) The ab-inirio calculation of the charge distribution on the cysteamine radioprotector cation shows that this molecule possesses a positive NH3 head and SH tail. (2) The XILO energy variations of the supermolecule (dideoxyrihe-triphosphate + cysteamine) show minimal zones which enable us to specify the positions and the distortion of the cysteamine radioprotector in interaction with the DNA backbone.

Conformation and electrostatic properties quantum determination of the new radioprotector and anticancer drug I-102

“…The geometries (bond lengths and bond angles) are those of our previous article [18] for cysteamine and those of glycine are taken from Ref. 19.…”

“…The geometries (bond lengths and bond angles) are those of our previous article [18] for cysteamine and those of glycine are taken from Ref. 19. In the absence of crystallographic data concerning the S1-C9 length and the C2-S1- C9 angle in 1-102 molecule, a special study was performed.…”

Simulation of the Radioprotective Action of Mercaptoethylamine Derivatives and its Analogues with their Quantum-Chemical and Information Features

“…In a fairly narrow range of energies 8eV ≤ ∆ε ≤ 9eV (group of chemical compounds Nos. [16][17][18][19][20][21][22][23][24] there is a significant change in the radio-protective properties of low molecular weight compounds. The energy interval ∆ε can be compared with the threshold processes of deexcitation of metastable states of biomacromolecules, associated both with the interception of migrating electronic excitation in the biosystem, as well as with the prevention of possible molecular conformational transitions.…”

“…From experiments [20,21] aimed at studying the radioprotective effect of cysteamine on mammalian cells, it is known that radio-protector molecules quickly penetrate into cells and reach nuclear DNA without difficulties associated with transport. Lowmolecular compounds can interact with DNA [22] and, thus, contribute to the stabilization of the macromolecule structure by participating in the dissipation of the excitation electronic energy into the conformational energy of the impurity nuclear subsystem. It is possible that conformational transitions induced by interaction with lowmolecular compounds lead to changes in the electronic state of the active groups of biomacromolecules and their mutual arrangement.…”