Characterization of the structure and melting behavior of the loop I fragment of ColE1 RNA I.
We have synthesized two RNA fragments: a 42-mer corresponding to the full loop I sequence of the loop I region of ColE1 antisense RNA (RNA I), plus three additional Gs at the 5'-end, and a 31-mer which has 11 5'-end nucleotides (G(-2)-U9) deleted. The secondary structure of the 42-mer, deduced from one- and two-dimensional NMR spectra, consists of a stem of 11 base-pairs which contains a U-U base-pair and a bulged C base, a 7 nucleotide loop, and a single-stranded 5' end of 12 nucleotides. The UV-melting study of the 42-mer further revealed a multi-step melting behavior with transition temperatures 32 degrees C and 71 degrees C clearly discernible. In conjunction with NMR melting study the major transition at 71 degrees C is assigned to the overall melting of the stem region and the 32 degrees C transition is assigned to the opening of the loop region. The deduced secondary structure agrees with that proposed for the intact RNA I and provides structural bases for understanding the specificity of RNase E.
Division of Structural Biology, Institute of Biomedical Sciences, Nankang, Taiwan, R.O.C.
T H
TH
Lin
H D
HD
Lin
J L
JL
Yang
V R
VR
Kaberdin
S
S
Lin-Chao
T H
TH
Huang
D001482:Base Composition; D009682:Magnetic Resonance Spectroscopy; D009690:Nucleic Acid Conformation; D010957:Plasmids / Q000235:genetics; D016372:RNA, Antisense / Q000737:chemistry*; D013696:Temperature
D016372:RNA, Antisense