Download MendeleyEffects of N2,N2-dimethylguanosine on RNA structure and stability: crystal structure of an RNA duplex with tandem m2 2G:A pairs.
Pallan, P.S., Kreutz, C., Bosio, S., Micura, R., Egli, M.(2008) RNA 14: 2125-2135
- PubMed: 18772248
- DOI: https://doi.org/10.1261/rna.1078508
- Primary Citation of Related Structures:
3CJZ - PubMed Abstract:
Methylation of the exocyclic amino group of guanine is a relatively common modification in rRNA and tRNA. Single methylation (N(2)-methylguanosine, m(2)G) is the second most frequently encountered nucleoside analog in Escherichia coli rRNAs. The most prominent case of dual methylation (N(2),N(2)-dimethylguanosine, m(2) (2)G) is found in the majority of eukaryotic tRNAs at base pair m(2) (2)G26:A44. The latter modification eliminates the ability of the N(2) function to donate in hydrogen bonds and alters its pairing behavior, notably vis-à-vis C. Perhaps a less obvious consequence of the N(2),N(2)-dimethyl modification is its role in controlling the pairing modes between G and A. We have determined the crystal structure of a 13-mer RNA duplex with central tandem m(2) (2)G:A pairs. In the structure both pairs adopt an imino-hydrogen bonded, pseudo-Watson-Crick conformation. Thus, the sheared conformation frequently seen in tandem G:A pairs is avoided due to a potential steric clash between an N(2)-methyl group and the major groove edge of A. Additionally, for a series of G:A containing self-complementary RNAs we investigated how methylation affects competitive hairpin versus duplex formation based on UV melting profile analysis.
Organizational Affiliation:
Department of Biochemistry, School of Medicine, Vanderbilt University, Nashville, Tennessee 37232, USA.
