Uracil in deoxyribonucleotide polymers reduces their template-primer activity for E. coli DNA polymerase I.
The physical and biochemical properties of two pairs of synthetic DNA template-primers were investigated. The copolymer poly(dA-dU) . poly(dA-dU) and the homopolymer duplex poly(dA). poly(dU) were characterized by a lower Tm and by a higher buoyant density value than the respective thymine polynucleotides poly(dA-dT) . poly(dA-dT) and poly(dA) . poly(dT). The polymerizing and the primer terminus adding reactions of a homogenous E. coli DNA polymerase I preparation, as measured by incorporation of [3H]dAMP into the acid-insoluble fraction, were significantly poorer with uracil-containing template-primers than with thymine templates. Moreover, the uracil-containing polynucleotides inhibited the polymerizing activity of DNA polymerase I to a greater extent than the thymine polynucleotides, when the enzymatic activity was investigated with a dATP/dTTP/dUTP-free incorporation system making use of poly(dI-dC) . poly(dI-dC) as the template-primer.
D004256:DNA Polymerase I / Q000378:metabolism*; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D003854:Deoxyribonucleotides; D004926:Escherichia coli / Q000201:enzymology*; D007700:Kinetics; D011061:Poly A; D011063:Poly A-U; D011067:Poly dA-dT / Q000031:analogs & derivatives; D011089:Polydeoxyribonucleotides; D013329:Structure-Activity Relationship; D013698:Templates, Genetic
D003854:Deoxyribonucleotides; D011089:Polydeoxyribonucleotides; D011063:Poly A-U; D011061:Poly A; C015465:poly(dA); D011067:Poly dA-dT; C020468:poly(d(A-U)); D004256:DNA Polymerase I; D004259:DNA-Directed DNA Polymerase