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7‐Deazapurine Oligodeoxyribonucleotides: The effects of 7‐deaza‐8‐methylguanine on dna structure and stability
Author(s) -
Seela Frank,
Chen Yaoming,
Mittelbach Cathrin
Publication year - 1998
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19980810310
Subject(s) - chemistry , phosphoramidite , duplex (building) , guanine , guanosine , stereochemistry , dna , phosphonate , residue (chemistry) , nucleotide , oligonucleotide , crystallography , combinatorial chemistry , biochemistry , gene
Oligodeoxyribonucleotides containing 7‐deaza‐2′‐deoxy‐8‐methylguanosine (m 8 c 7 G d ; 2b ) were prepared. For this purpose, the phosphonate 3a and the phosphoramidite 3b were synthesized and employed in solidphase oligodeoxyribonucleotide synthesis. The structures and the thermodynamic data of duplex formation of oligodeoxyribonucleotides containing 2b were investigated by temperature‐dependent CD and UV spectra and compared with those containing 7‐deaza‐2′‐deoxy‐7‐methylguanosine (m 7 c 7 G d ) or 7‐deaza‐2′‐deoxy‐guanosine (c 7 G d ; 2a ). In general, compound 2b reduces the duplex stability. In case of the sequence d(m 8 c 7 G‐C) 4 (18) , the B → Z transition was facilitated by the incorporation of 2b . Moreover, a single 7‐deaza‐8‐methylguanine residue present in an oligodeoxyribonucleotide tract of guanine residues destabilizes the dG quadruplex significantly. This destabilization is more pronounced than in the case of 7‐deazaguanine or 7‐deaza‐7‐methyl‐guanine.