Limits of RNA 2 '-OH Mimicry by Fluorine: Crystal Structure of Bacillus halodurans RNase H Bound to a 2 '-FRNA:DNA Hybrid

作者：Pallan Pradeep S; Prakash Thazha P; de Leon Arnie R; Egli Martin^*

来源：Biochemistry, 2016, 55(38): 5321-5325.

DOI：10.1021/acs.biochem.6b00849

RNase H1 cleaves the RNA strand of RNA:DNA hybrids. Replacement of RNA 2'-hydroxyls by fluorine (FRNA) is commonly used to stabilize aptamers and siRNAs. However, FRNA:DNA hybrids fail to elicit RNase H activity. The underlying reasons are unclear, as 2'-OH groups are not directly involved in cleavage. We determined the crystal structure of Bacillus halodurans RNase H bound to a FRNA:DNA hybrid. The structure points to dynamic (slippage of the FRNA:DNA hybrid relative to the enzyme), geometric (different Curvatures of FRNA:DNA and RNA:DNA hybrids), and electronic reasons (Mg2+ absent from the active site of the FRNA:DNA complex) for the loss of RNaseH activity.

• 出版日期2016-9-27