3'-minor groove binder-DNA probes increase sequence specificity at PCR extension temperatures

Nucleic Acids Res. 2000 Jan 15;28(2):655-61. doi: 10.1093/nar/28.2.655.

Abstract

DNA probes with conjugated minor groove binder (MGB) groups form extremely stable duplexes with single-stranded DNA targets, allowing shorter probes to be used for hybridization based assays. In this paper, sequence specificity of 3'-MGB probes was explored. In comparison with unmodified DNA, MGB probes had higher melting temperature (T(m)) and increased specificity, especially when a mismatch was in the MGB region of the duplex. To exploit these properties, fluorogenic MGB probes were prepared and investigated in the 5'-nuclease PCR assay (real-time PCR assay, TaqMan assay). A 12mer MGB probe had the same T(m)(65 degrees C) as a no-MGB 27mer probe. The fluorogenic MGB probes were more specific for single base mismatches and fluorescence quenching was more efficient, giving increased sensitivity. A/T rich duplexes were stabilized more than G/C rich duplexes, thereby leveling probe T(m)and simplifying design. In summary, MGB probes were more sequence specific than standard DNA probes, especially for single base mismatches at elevated hybridization temperatures.

MeSH terms

  • Base Pair Mismatch
  • Base Sequence
  • DNA Primers
  • DNA Probes / metabolism*
  • Hot Temperature
  • Nucleic Acid Hybridization
  • Oligodeoxyribonucleotides / chemical synthesis
  • Oligodeoxyribonucleotides / chemistry
  • Polymerase Chain Reaction

Substances

  • DNA Primers
  • DNA Probes
  • Oligodeoxyribonucleotides