Nuclear Overhauser effect study of yeast tRNAVal 1: evidence for uridine-pseudouridine base pairing

The proton NMR spectrum of yeast tRNAVal 1 has been studied using nuclear Overhauser effect (NOE), including comparison of NOE patterns between purine C8 deuterated and nondeuterated samples. Studies of the downfield region enable us to reliably assign many resonances in the acceptor and D stems. Prominent among these reliable assignments is that of the unusual base pair U psi, which is made here for the first time. Other identifications include GU2, U8-A14, the three AU base pairs of the acceptor stem, and N1 and N3 protons of psi 55.