Effects of N[superscript 2],N[superscript 2]-dimethylguanosine on RNA structure and stability: Crystal structure of an RNA duplex with tandem m[superscript 2 subscript 2]G:A pairs

Journal Article · Mon Dec 15 04:00:00 EST 2008 · RNA

DOI:https://doi.org/10.1261/rna.1078508· OSTI ID:1007011

Pallan, Pradeep S; Kreutz, Christoph; Bosio, Silvia; Micura, Ronald; Egli, Martin ^[1]

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1. Innsbruck University

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-a-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.

• Research Organization: Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
• Sponsoring Organization: USDOE
• OSTI ID: 1007011
• Journal Information: RNA, Journal Name: RNA Journal Issue: 10, 2008 Vol. 14
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

08 HYDROGEN
36 MATERIALS SCIENCE
BEHAVIOR
CRYSTAL STRUCTURE
ESCHERICHIA COLI
FUNCTIONS
GUANINE
HYDROGEN
MELTING
METHYLATION
MODIFICATIONS
NUCLEOSIDES
POTENTIALS
RNA
STABILITY