bi0473399_si_001.pdf (839.42 kB)
Comparison of the Global Structure and Dynamics of Native and Unmodified tRNAval†
journal contribution
posted on 2005-04-26, 00:00 authored by Annaleen Vermeulen, Scott A. McCallum, Arthur PardiThe effects of post-transcriptional modifications on the structure and dynamics of Escherichia
coli tRNAval were studied by NMR spectroscopy. NMR chemical shift data and residual dipolar couplings
were used to show that the local secondary and tertiary structures are very similar in native and unmodified
tRNAval. Rigid body restrained molecular dynamics calculations showed that the global structure of tRNA
is unchanged by the post-transcriptional modifications. Deuterium exchange NMR experiments were used
to probe the dynamics and flexibility of native and unmodified tRNAval. A similar set of slowly exchanging
(t1/2 > 3 min) imino protons were observed in both tRNAs, but the rates of exchange for the slowest
exchanging imino protons were ∼20 times faster in unmodified than in native tRNA. These results
demonstrate that the dynamics and flexibility of tRNAval, but not the local or global structure, are
significantly affected by post-transcriptional modifications.