Temperature-dependent 31P n.m.r. shifts to assess the conformations of branched tri- and tetra-nucleotides which are formed as lariats in the splicing reactions

Abstract

Temperature-dependent changes of ³¹P n.m.r. chemical shifts (Δδ) have been used to estimate the secondary structure of branched tri- and tetra-nucleotides formed in the splicing reaction; these studies have provided independent evidence, confirming our earlier ¹H n.m.r. studies, that the 2′→ 5′ stacking is the predominant structural feature that dictates the secondary structure of the branched trinucleotides while the branched tetranucleotides exist in the form of a distorted A-RNA helix without any 2′→ 5′ stacking.