The mechanism of conformational proofreading is utilized in the system of homologous recombination to discern between similar DNA sequences. Homologous recombination facilitates the exchange of genetic material between homologous DNA molecules. This crucial process requires detecting a specific homologous DNA sequence within a huge variety of heterologous sequences. The detection is mediated by RecA in E. coli, or members of its superfamily in other organisms. RecA first polymerizes along a stretch of single-stranded DNA, and then this protein-DNA filament searches for homology along double-stranded DNA. In the RecA-DNA filament, the distance between bases increases significantly with respect to the bare 3.4 Å in the double-strand (by 50% on average). 
This sets a significant energetic barrier on the search, since the double-stranded DNA has to stretch by the same magnitude to check for homology. 
By formulating the DNA recognition process as a signal detection problem, it was shown that the experimentally observed RecA-induced DNA deformation and the binding energetics are fine-tuned to ensure optimal sequence detection. The amount of deformation is such that binding to homologous DNA sequences only slightly decreases, while binding to wrong sequences decreases significantly. This is exactly the conformational proofreading mechanism.