NMR Studies and Minimum Energy Conformation Calculations on the 5′-Terminus of Mammalian mRNA

Abstract

The 5′-terminal region of a wide variety of mRNAs of eukaryotes contain an unusual sequence of nucleosides in which the terminal is 7-methylguanosine(Rottman et al. 1974). In this structure the 5′ hydroxyl of 7-methylguanosine is connected through a triphosphate bridge to the 5′ hydroxyl of 2′–0-methylated nucleosides. It has been shown that this unusual sequence is necessary for mRNA to carry out in vitro translation with fidelity (Adams and Cory, 1975; Furuichi et al, 1977). To understand the structure-function relationships we have explored whether the presence of 7-methylated guanosine at the terminus endows any unique stereochemical features to mRNAs. The conformational properties of 7-methylguanosine-5′ monophosphate (7-Me-5′ GMP) and 5′ GMP have been studied using NMR spectroscopy and theoretical calculations using classical potential functions.