Extensive backbone dynamics in the GCAA RNA tetraloop analyzed using 13C NMR spin relaxation and specific isotope labeling.

ABSTRACT: Conformational dynamics play a key role in the properties and functions of proteins and nucleic acids. Heteronuclear NMR spin relaxation is a uniquely powerful site-specific probe of dynamics in proteins and has found increasing applications to nucleotide base side chains and anomeric sites in RNA. Applications to the nucleic acid ribose backbone, however, have been hampered by strong magnetic coupling among ring carbons in uniformly 13C-labeled samples. In this work, we apply a recently developed, metabolically directed isotope labeling scheme that places 13C with high efficiency and specificity at the nucleotide ribose C2' and C4' sites. We take advantage of this scheme to explore backbone dynamics in the well-studied GCAA RNA tetraloop. Using a combination of CPMG (Carr-Purcell-Meiboom-

SUBMITTER: Johnson JE 

PROVIDER: S-EPMC2729180 | biostudies-literature | 2008 Dec

REPOSITORIES: biostudies-literature