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Publication Abstract from PubMed

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.

Limits of RNA 2'-OH Mimicry by Fluorine: Crystal Structure of Bacillus halodurans RNase H Bound to a 2'-FRNA:DNA Hybrid.,Pallan PS, Prakash TP, de Leon AR, Egli M Biochemistry. 2016 Sep 14. PMID:27611889^[2]

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