Li G, Xiao W, Torrence PF. Synthesis and properties of second-generation 2-5A-antisense chimeras with enhanced resistance to exonucleases.
J Med Chem 1997;
40:2959-66. [PMID:
9288179 DOI:
10.1021/jm970227d]
[Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In order to stabilize 2-5A-antisense chimeras to exonucleases, we have synthesized chimeric oligonucleotides in which the last phosphodiester bond at the 3'-terminus of the antisense domain was inverted from the usual 3',5'-linkage to a 3',3'-linkage. The preparation of such analogues was accomplished through standard phosphoramidite chemistry with the use of a controlled pore glass solid support with a nucleoside attached through its 5'-hydroxyl, thereby permitting elongation at the 3'-hydroxyl. The structures of such terminally inverted linkage chimeras of the general formula pA4-[pBu]2-(pdNn3'-3'dN) were corroborated by a combination of snake venom phosphodiesterase digestion in the presence or absence of bacterial alkaline phosphatase. Most characteristically, the presence of the 3'-terminal-inverted phosphodiester linkage produced an unnatural dinucleotide of general composition dN3'p3'dM. These structures could be confirmed by independent synthesis and fast atom bombardment mass spectroscopy (FAB). 2-5A-Antisense chimeras of this structural class, pA4-[pBu]2-(pdNn'3-3'dN), were 5-6-fold more stable than their unmodified congeners, pA4-[pBu]2-(pdN)n, to degradation by a representative phosphodiesterase from snake venom. In 10% human serum, the new 2-5A-antisense chimeras, pA4-[pBu]2-(pdNn3'-3'dN), possessed a half-life that was 28-fold longer than that of the unmodified chimeras. These results provide entry to a second generation of 2-5A-antisense chimeras.
Collapse