Display of 8-hydroxy-GTP substrate properties of UTP in the reaction of polynucleotide synthesis catalyzed by RNA-polymerase from Escherichia coli in the presence of poly[d (AT) .d (AT) ] template
Bruskov, V.I.; Kuklina, O.V.
Molekuliarnaia Biologiia 22(3): 726-730
1988
ISSN/ISBN: 0026-8984 PMID: 3054496 Document Number: 312990
8-oxy-GTP was obtained via reaction of GTP with ascorbic acid and addition of hydrogen peroxide. 8-oxy-GTP is recognized and displays substrate properties of UTP on substitution of 8-oxy-GTP for UTP in polynucleotide synthesis catalyzed by E. coli RNA polymerase on a poly[d(A-T)].poly[d(A-T)] template. Such incorporation does not take place at equimolar quantities of GTP and 8-Br-GTP. The incorporation of 8-oxy-GTP instead of UTP, is 2.5-3 times higher upon replacement of Mg2+ by Mn2+ ions. The dinucleotide ApU serving as an initiator rises the incorporation level of 8-oxy-GTP both for Mg2+ and Mn2+ ions. 8-oxy-GTP slightly inhibits poly[r(A-U)] synthesis, but UTP strongly inhibits the incorporation of 8-oxy-GTP. [alpha-32P] 8-oxy-GTP is incorporated mainly instead of UTP, but it can be incorporated also during the substitution of 8-oxy-GTP for ATP.