1osu
From Proteopedia
STRUCTURE OF THE RNA HEXAMER, R(UUCGCG), WITH A 5'-UU-OVERHANG EXHIBITING HOOGSTEEN-LIKE TRANS U-U BASE PAIRS
Overview
The crystal structure of the RNA fragment, 5'-r(UUCGCG)-3', has been determined at 1.4 A resolution by a combination of single isomorphous replacement and molecular search methods. The 3'-terminal CGCG portion of the hexamer engages in Watson-Crick hydrogen bonding while the 5'-terminal UU-overhang forms novel Hoogsteen-like U.U self-base pairs with the overhang of an adjacent duplex. The U.U pairs display a single conventional hydrogen bond between O4 (U1) and N3 (U8) and a CH-O hydrogen bond between C5-H (U1) and O4 (U8), through the Hoogsteen face of the pyrimidine base U1. This unusual arrangement of one of the bases results in a trans U.U pair on antiparallel strands in contrast to the usual cis base pairs. The structure emphasizes the pronounced polymorphism of U.U pairs and has implications for folding of RNA molecules.
About this Structure
Full crystallographic information is available from OCA.
Reference
The structure of r(UUCGCG) has a 5'-UU-overhang exhibiting Hoogsteen-like trans U.U base pairs., Wahl MC, Rao ST, Sundaralingam M, Nat Struct Biol. 1996 Jan;3(1):24-31. PMID:8548450 Page seeded by OCA on Sat May 3 04:14:31 2008
