RNA bulges and the helical periodicity of double-stranded RNA.

摘要: RNA MOLECULES typically exhibit extensive secondary structure, including double-stranded duplex, hairpins, internal loops, bulged bases and pseudoknotted1,2 structures (reviewed in refs 3 4). This is intimately connected with biological function, splicing reactions5,6 ribozyme activity7,8. The formation of RNA–DNA hybrids important the transcription DNA, reverse viral RNA, DNA replication. Bulged helices are potentially significant folding providing sites for specific protein–RNA interactions, as illustrated by TFIIIA Xenopus9and coat protein phage R17 (ref. 10). Most information about structure derives from fibre diffraction11,12 or crystallography natural molecules, notably transfer RNA13–17, but until recently there have been few systematic studies using designed sequences18–22. We used gel electrophoresis to investigate properties both duplexes solution. As helices23–25, bulges introduce pronounced kinks into helices, depending on number types bulge its position fragment. By varying spacing between two bulge-induced kinks, we measured periodicity