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Synthesis and Use of Modified Peptide Nucleic Acids for Visual Detection of DNA

Synthesis and Use of Modified Peptide Nucleic Acids for Visual Detection of DNA

[(S,S)-Trans-1,2-Cyclopentane Diamine-Modified and Gamma-Lysine-Modified-Peptide Nucleic Acids as Probes for Nucleic Acid Detection: Synthesis and Application]

Modification of peptide nucleic acids (PNAs) by the incorporation of trans-1,2-diaminocyclopentane into the PNA provides for more highly sensitive and selective detection of DNA and RNA sequences. The compounds disclosed in this invention have the potential for use in the development of nucleic acid detection kits for various pathogens.

Genomic analysis can provide key diagnostic information about the presence of pathogens or disease. At the present time DNA-based devices, such as DNA microarrays, are used for such an analysis. However, most of these analyses require the amplification of the DNA under investigation. Replacing the DNA probe with peptide nucleic acid (PNA) greatly facilitates the DNA detection because the binding strength of PNAs to complementary DNA is stronger than DNA binding to complementary DNA. Strong binding between PNA and DNA can eliminate the need for prior DNA amplification. Furthermore, PNAs bind to DNAs under low salt conditions, which disfavor formation of double-stranded DNA. By operating under low salt conditions, DNA can be denatured to ensure that target sequences are available for binding to a PNA probe. In addition, PNA is a synthetic molecule that cannot be broken down by enzymes, so the stability of PNAs allow for a device with a longer shelf life than one made from DNA. This technology also permits the presence of complementary DNA to be detected by eye (i.e. without instrumentation).

Applications:

The PNAs that have been synthesized in this invention may be adapted for detecting an infectious agent, such as anthrax, avian flu, severe acute respiratory syndrome (SARS), human papilloma virus (HPV), or human immunodeficiency virus (HIV). Other applications include:


DNA analysis in biochemical research
Chiral synthesis
Diagnosis of pathogens in the environment
Diagnosis of disease

Advantages:

Peptide nucleic acids do not need refrigeration
Binding to complementary DNA can be detected by eye
Complementary double-stranded DNA can be detected without prior dissociation

Development Status:

PNA backbone structure has been improved by incorporation of cyclopentane rings in the PNA backbone.
An improved synthesis of cyclopentane-containing PNA has been developed
Visual detection of anthrax DNA has been demonstrated.
Patent Status:

DHHS Reference No. E-308-2006, a provisional patent application has been filed.

Licensing Contact:

Dr. Susan M. Carson, 301-435-5020, carsons@od.nih.gov

National Institutes of Health. April 2007.