Sequence-specific detection of individual DNA strands using engineered nanopores
Stefan Howorka1, Stephen Cheley1
& Hagan Bayley1, 2
1
Department of Medical Biochemistry and Genetics, The Texas A&M University System Health Science Center, 440 Reynolds Medical Building, College Station, TX 77843-1114.
2
Department of Chemistry, Texas A&M University, College Station, TX 77843-3255.
We describe biosensor elements that are capable of identifying individual DNA strands with single-base resolution. Each biosensor element consists of an individual DNA oligonucleotide covalently attached within the lumen of the -hemolysin (HL) pore to form a "DNA−nanopore". The binding of single-stranded DNA (ssDNA) molecules to the tethered DNA strand causes changes in the ionic current flowing through a nanopore. On the basis of DNA duplex lifetimes, the DNA−nanopores are able to discriminate between individual DNA strands up to 30 nucleotides in length differing by a single base substitution. This was exemplified by the detection of a drug resistance−conferring mutation in the reverse transcriptase gene of HIV. In addition, the approach was used to sequence a complete codon in an individual DNA strand tethered to a nanopore.
-hemolysin (
