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001-es BibID:	BIBFORM031408
035-os BibID:	WOS:000246842300026 PMID:17497910
Első szerző:	Solt Iván
Cím:	Electrostatic versus nonelectrostatic effects in DNA sequence discrimination by divalent ions Mg2+ and Mn2+ / Iván Solt, István Simon, Attila G. Császár, Monika Fuxreiter
Dátum:	2007
ISSN:	1520-6106
Megjegyzések:	Mg(2+) and Mn(2+) ions are critical to the functioning of phosphoryl transfer enzymes, such as restriction endonucleases. Although these ions play similar roles in the chemical steps, they govern substrate specificity via modulating sequence discrimination by up to a factor of 10(5) with Mg(2+) and only up to a factor of 10 with Mn(2+). To explain whether such diversity originates in fundamental differences in the electronic structures of the nucleobase-hydrated-metal ion complexes, structures and interaction energies were determined at the density functional (DFT) and second-order Moller-Plesset (MP2) levels of theory. Although both metal ions favor identical binding sites, Mn(2+) complexes exhibit greater distortions from the ideal octahedral geometry and larger variability than the corresponding Mg(2+) systems. In inner-shell complexes, with direct contact between the metal and the nucleobase, Mg(2+) is preferred over Mn(2+) in the gas phase, due primarily to nonelectrostatic effects. The interaction energies of the two metal ions are more similar in the outer-shell complexes, likely due to reduced charge transfer between the hydrated metal ion and the base moieties. Inclusion of solvation effects can amplify the relative nucleobase preferences of Mg(2+) and Mn(2+), indicating that bulk hydration modulates the balance between electrostatic and nonelectrostatic terms. In most cases, the base substitutions in solution are facilitated more by Mn(2+) than by Mg(2+). Electrostatic properties of the environment were demonstrated to have a major influence on the nucleobase preferences of the two metal ions. Overall, quantum chemical calculations suggest that the contrasting selectivity of Mg(2+) and Mn(2+) cofactors toward nucleobases derives from the larger flexibility of the Mn(2+) complexes accompanied by the excessive polarization and charge-transfer effects as well as less favorable solvation.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban egyetemen (Magyarországon) készült közlemény
Megjelenés:	The journal of physical chemistry. B. - 111 : 22 (2007), p. 6272-6279. -
További szerzők:	Simon István Császár Attila G. (1959-) (kémikus) Fuxreiter Mónika (1969-) (kutató vegyész)
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat DOI
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