The solution structure of the self-complementary deca-ribonucleotide 5'- r(GCGA*AUUCGC)-3' containing 9-[2-O-(β-D-ribofuranosyl)-β-D- ribofuranosyl]adenine (A*), a modified nucleotide that occurs in lower eukaryotic methionine initiator tRNAs (tRNAs(i)(Met)), was determined by NMR spectroscopy. Unexpectedly, the modification has no effect on the thermal stability of the duplex. However, the extra ribose moiety is in the C(3')- endo conformation and takes up a well-defined position in the minor groove, which is in agreement with its position in tRNAs(i)(Met) as determined by X- ray crystallography. Molecular-dynamics simulations on the RNA duplex in H 2 O show that the position of the extra ribofuranose moiety seems to be stabilized by bridged H-bonds (mediated by two H 2 O molecules) to the backbone of the complementary chain.

Original publication

DOI

10.1002/1522-2675(20000607)83:6<1278::AID-HLCA1278>3.0.CO;2-Q

Type

Journal article

Journal

Helvetica Chimica Acta

Publication Date

01/01/2000

Volume

83

Pages

1278 - 1289