Synthesis and Biophysical Properties of Arabinonucleic Acids (ANA): Circular Dichroic Spectra, Melting Temperatures, and Ribonuclease H Susceptibility of ANA·RNA Hybrid Duplexes
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- 作者：Anne M. Noronha ; Christopher J. Wilds ; Chun-Nam Lok ; Katya Viazovkina ; Dominique Arion ; Michael A. Parniak ; and Masad J. Damha
- 刊名：Biochemistry
- 出版年：2000
- 出版时间：June 20, 2000
- 年：2000
- 卷：39
- 期：24
- 页码：7050 - 7062
- 全文大小：902K
- 年卷期：v.39,no.24(June 20, 2000)
- ISSN：1520-4995
文摘
Arabinonucleic acid (ANA), the 2'-epimer of RNA, was synthesized from arabinonucleosidebuilding blocks by conventional solid-phase phosphoramidite synthesis. In addition, the biochemical andphysicochemical properties of ANA strands of mixed base composition were evaluated for the first time.ANA exhibit certain characteristics desirable for use as antisense agents. They form duplexes withcomplementary RNA, direct RNase H degradation of target RNA molecules, and display resistance to3'-exonucleases. Since RNA does not elicit RNase H activity, our findings establish that the stereochemistryat C2' (ANA versus RNA) is a key determinant in the activation of the enzyme RNase H. Inversion ofstereochemistry at C2' is most likely accompanied by a conformational change in the furanose sugarpucker from C3'-endo (RNA) to C2'-endo ("DNA-like") pucker (ANA) [Noronha and Damha (1998)Nucleic Acids Res. 26, 2665-2671; Venkateswarlu and Ferguson (1999) J. Am. Chem. Soc. 121, 5609-5610]. This produces ANA/RNA hybrids whose CD spectra (i.e., helical conformation) are more similarto the native DNA/RNA substrates than to those of the pure RNA/RNA duplex. These features, combinedwith the fact that ara-2'OH groups project into the major groove of the helix (where they should notinterfere with RNase H binding), help to explain the RNase H activity of ANA/RNA hybrids.