Synthesis of oligodeoxynucleotides containing 2-thiopyrimidine residues--a new protection scheme.
A method is described for the incorporation of 2'-deoxy-2-thiouridine (dS2U) and 2'-deoxy-2-thiothymidine (dS2T) into oligodeoxynucleotides at predetermined positions. This requires N3 or O4-acylation of dS2U and dS2T with toluoyl chloride. These base-protected thiopyrimidines are completely stable toward the aqueous iodine oxidation reagent used in the phosphoramidite DNA synthesis method. The toluoyl protecting group is removed during the standard post-synthetic ammonia treatment. This novel protection strategy allows dS2U and dS2T to be efficiently incorporated into oligodeoxynucleotides at predetermined sites without the usual problem of desulfurization and decomposition. Several 14-mers containing the Eco-RI recognition site (dGGCGGAAXXCCGCC and dGGCGGAAXXCGCGG, where X represents dT, dS2U or dS2T) have been synthesized and characterized by base composition, thermal denaturation, CD spectroscopy and endonuclease substrate activity.
Kuimelis
R G
RG
Department of Chemistry, University of California, Davis 95616.
Nambiar
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KP
D001483:Base Sequence; D002942:Circular Dichroism; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009691:Nucleic Acid Denaturation; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis* / Q000737:chemistry / Q000302:isolation & purification; D013873:Thionucleotides / Q000737:chemistry*; D013891:Thiouridine / Q000031:analogs & derivatives / Q000737:chemistry*; D013936:Thymidine / Q000031:analogs & derivatives / Q000737:chemistry*
D009838:Oligodeoxyribonucleotides; D013873:Thionucleotides; D013891:Thiouridine; D013936:Thymidine