4iqs

Publication Abstract from PubMed

Unlike DNA, in addition to the 2'-OH group, uracil nucleobase and its modifications play essential roles in structure and function diversities of non-coding RNAs. Non-canonical U*U base pair is ubiquitous in non-coding RNAs, which are highly diversified. However, it is not completely clear how uracil plays the diversifing roles. To investigate and compare the uracil in U-A and U*U base pairs, we have decided to probe them with a selenium atom by synthesizing the novel 4-Se-uridine ((Se)U) phosphoramidite and Se-nucleobase-modified RNAs ((Se)U-RNAs), where the exo-4-oxygen of uracil is replaced by selenium. Our crystal structure studies of U-A and U*U pairs reveal that the native and Se-derivatized structures are virtually identical, and both U-A and U*U pairs can accommodate large Se atoms. Our thermostability and crystal structure studies indicate that the weakened H-bonding in U-A pair may be compensated by the base stacking, and that the stacking of the trans-Hoogsteen U*U pairs may stabilize RNA duplex and its junction. Our result confirms that the hydrogen bond (O4(...)H-C5) of the Hoogsteen pair is weak. Using the Se atom probe, our Se-functionalization studies reveal more insights into the U*U interaction and U-participation in structure and function diversification of nucleic acids.

Structural insights of non-canonical U*U pair and Hoogsteen interaction probed with Se atom.,Sheng J, Gan J, Soares AS, Salon J, Huang Z Nucleic Acids Res. 2013 Dec 1;41(22):10476-87. doi: 10.1093/nar/gkt799. Epub 2013, Sep 5. PMID:24013566^[1]

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