1c4l

Publication Abstract from PubMed

The formation of the C-U base pair in a duplex was observed in solution by means of the temperature profile of (15)N chemical shifts, and the precise geometry of the C-U base pair was also determined by NOE-based structure calculation. From the solution structure of the RNA oligomer, r[CGACUCAGG].r[CCUGCGUCG], it was found that a single C-U mismatch preferred being stacked in the duplex rather than being flipped-out even in solution. Moreover, it adopts an irregular geometry, where the amino nitrogen (N4) of the cytidine and keto-oxygen (O4) of the uridine are within hydrogen-bonding distance, as seen in crystals. To further prove the presence of a hydrogen bond in the C-U pair, we employed a point-labeled cytidine at the exocyclic amino nitrogen of the cytidine in the C-U pair. The temperature profile of its (15)N chemical shift showed a sigmoidal transition curve, indicating the presence of a hydrogen bond in the C-U pair in the duplex.

Solution structure of an RNA duplex including a C-U base pair.,Tanaka Y, Kojima C, Yamazaki T, Kodama TS, Yasuno K, Miyashita S, Ono A, Ono A, Kainosho M, Kyogoku Y Biochemistry. 2000 Jun 20;39(24):7074-80. PMID:10852704^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.