In a one-step reaction, DNA strands with the appropriate signal-generating moieties (probes) attached can be used in a simple, one-step “no-wash” method. Neither DPC™ probe is capable of generating a signal independently, creating a system of essentially “zero background”. Because the reactions can be performed under aqueous conditions at neutral pH and room temperature, the system is well suited for in situ, in vitro and in vivo applications.

Nucleic Acids

For nucleic acid detection, two hybridization probes bind to nucleic acid analytes and bring signaling precursors together for DPC-mediated signal generation. These precursors to the signaling compound do not signal themselves and thus our detection systems have extremely low background, resulting in high signal-noise ratios and sensitivity. When in close proximity, i.e. upon binding of associated recognition elements on a target nucleic acid (DNA or RNA) molecule, these probes undergo a DPC-mediated chemical reaction to produce a signaling product.

Proteins and Protein Complexes

Protein DPC uses two separate probes that recognize two elements of the protein. Each probe has a recognition element (e.g. antibody) and a signaling precursor (see figure below).

Target recognition and signal generation by DPC probes. *Recognition moiety may be any molecule such as antibody, aptamer, peptide, or small molecule. Target may be a protein, protein complex or protein modification

As two binding events are required to generate the signaling event, the system allows one to measure two sites (epitopes) on a single protein, or on a pair of proteins bound to one another in a complex. This provides a means to obtain “functional” information about cell signaling events by detecting key changes in individual proteins, such as how they are modified (post-translational modification) or how they interact with other proteins in complexes.

Forming the DNA duplex enables the sample recognition elements to act cooperatively to generate increased avidity. The formation of a ternary complex provides enhanced specificity and diminished false positive and false negative rates. The format facilitates detection of proteins in their functional context and is ideal for measuring homo- or heterodimers, fusion proteins, auto-antibodies and components of signaling pathways.

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