Pairing properties of the methylester of 5-carboxymethyl uridine in the wobble position of yeast tRNA3Arg.

At optimum magnesium concentration (10 mM) both yeast tRNA1Arg and tRNA3Arg are able to bind to poly (A,G) and A-G-A in presence of Escherichia coli robisomes. With A-G-G only tRNA1Arg ginds, wherea tRNA3Arg (anticodon mcm5 U-C-U) is not bound. This result means that the methylcarboxymethyl substituant in position 5 of U prevents its wobble with G.