Kinetic analysis of the template effect in ribooligoguanylate elongation

The paper presents kinetic studies on the reaction of elongation of the 3-prime-5-prime-linked ribooligoguanylates with guanosine 5-prime-phospho-2-methylimidazolide (2-MelmpG) in the presence or absence of a complementary template, the polycytidylic acid. In the absence of poly(C), the reaction leads to three isomeric oligomers that are elongated by one monomer unit: the 3-prime-5-prime linked, the 2-prime-5-prime linked, and the pyrophosphate, formed in a ratio of 1:2:5. In the presence of the template, the reaction is 20-fold faster and yields products (n + 1), (n + 2), (n + 3), etc., as long as 2-MelmpG is available. The formation of the natural, 3-prime-5-prime-linked isomer, is enhanced selectively by 140-fold at 37 C, and its relative yield increases with decreasing temperature.