title: Molecular dynamics DFT:B3LYP study of guanosinetriphosphate conversion into guanosinemonophosphate upon Mg2+ chelation of alpha and beta phosphate oxygens of the triphosphate tail.
abstract: A molecular dynamics DFT:B3LYP (6-31G(**) basis set) study is used to elucidate the mechanism of guanosinetriphosphate (GTP) conversion into guanosinemonophosphate (GMP) upon the action of Mg(2+) (magnesium cofactor). The computations are carried out at 310 K in a volume of 178 water molecules, which surround the Mg(2+)-GTP complex and imitate the effect of solution. Over 5 ps, Mg(2+)-GTP appears to be fully decomposed, yielding five final products: two hydrated molecules of inorganic phosphate Pi, a hydrated Mg(2+), atomic oxygen (which in the course of a couple of subsequent reactions gains two hydrogens and converts into a water molecule) and a highly active *GMP radical. The radical production is linked to presence of Mg(2+), which initiates a radical mechanism of GTP cleavage. At the initial stage, Mg(2+) undergoes reduction to Mg(+), accompanied by the formation of an ion-radical pair with GTP, (+)Mg*-*GTP(3-). Without Mg(2+), an inert form of GMP (the ionic mechanism of GTP hydrolytic cleavage) rather than GMP is produced. *GMP production, which is similar to that of *AMP (adenosinemonophosphate), *CMP (cytidinemonophosphate), TMP (thymidinemonophosphate) and *UMP (uridinemonophosphate), plays a crucial role in DNA and RNA single chain synthesis.
authors.affiliation: Saint-Petersburg State University, Universitetskaya Embankment 7/9, Saint-Petersburg, 199034, Russian Federation. clarisse@svs.ru
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Tulub
mesh_terms: D002614:Chelating Agents / Q000737:chemistry*; D004247:DNA / Q000138:chemical synthesis; D006157:Guanosine Monophosphate / Q000737:chemistry*; D006160:Guanosine Triphosphate / Q000737:chemistry*; D006868:Hydrolysis; D008274:Magnesium / Q000737:chemistry*; D008956:Models, Chemical; D008968:Molecular Conformation; D010100:Oxygen / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry*; D011122:Polyphosphates / Q000737:chemistry*; D011742:Pyrimidine Nucleotides / Q000737:chemistry; D012313:RNA / Q000138:chemical synthesis
chemical_list: D002614:Chelating Agents; D010710:Phosphates; D011122:Polyphosphates; D011742:Pyrimidine Nucleotides; D012313:RNA; D006157:Guanosine Monophosphate; D006160:Guanosine Triphosphate; D004247:DNA; D008274:Magnesium; C005692:triphosphoric acid; D010100:Oxygen