Enhanced probe binding
Methods for enhancing the binding of oligonucleotide probes to DNA and RNA are disclosed. The methods make use of thermodynamic and kinetic effects to reduce probe mismatches and failure of complementary probes to bind to DNA and RNA templates. Mapping and sequencing of the probed DNA and RNA samples are contemplated herein.
1. A method for producing a biomolecule analyte, the method comprising:
a) providing a single-stranded DNA or RNA template comprising (i) two or more secondary structures and (ii) a plurality of probe recognition sites comprising at least two different types of nucleotide recognition sites complementary to at least two different types of sequence-specific oligonucleotide probes, wherein each type of nucleotide recognition sites of the at least two different types of nucleotide recognition sites comprises multiple identical nucleotide recognition sites;
b) hybridizing a first type of the at least two different types of sequence-specific oligonucleotide probes to the template such that multiple probes of the first type of the at least two different types of sequence-specific oligonucleotide probes bind to the multiple identical nucleotide recognition sites of the first type of nucleotide recognition sites of the at least two different types of recognition sites and form a hybridized template comprising multiple probes of the first type of the at least two different types of sequence-specific oligonucleotide probes;
c) after the hybridizing step, conducting a base extension reaction from a 3′ end of each of the multiple probes of the first type of the at least two different types of sequence-specific oligonucleotide probes along the hybridized template comprising multiple probes of the first type of the at least two different types of sequence-specific oligonucleotide probes;
d) terminating the base-extension reaction after step c) is conducted for a time period such that (i) the multiple probes of the first type of the at least two different types of sequence-specific oligonucleotide probes are securely hybridized to the template and (ii) other types of recognition sites of the at least two different types of recognition sites of the hybridized template are left unoccupied, thereby forming a base extension product comprising the hybridized template;
e) after step d), applying heat or chemicals to the base extension product to denature the hybridized template such that at least a portion of said two or more secondary structures of the hybridized template is broken, thereby forming a denatured DNA or RNA comprising the multiple probes of the first type of the at least two different types of sequence-specific oligonucleotide probes; and
f) thereafter, performing steps b) to d) by hybridizing a second type of the at least two different types of sequence-specific oligonucleotide probes to the denatured DNA or RNA, thereby producing the biomolecule analyte, wherein the biomolecule analyte comprises DNA or RNA (i) comprising a reduced number of the secondary structures and (ii) comprising multiple probes of the first type of the at least two different types of sequence-specific oligonucleotide probes and multiple probes of the second type of the at least two different types of sequence-specific oligonucleotide probes, wherein the first type of the at least two different types of sequence-specific oligonucleotide probes and the second type of the at least two different types of sequence-specific oligonucleotide probes have different nucleotide sequences and are hybridized to different types of nucleotide recognition sites of the at least two different types of nucleotide recognition sites.
2. The method of claim 1 , wherein the denaturing step comprises applying the heat to the base extension product.
3. The method of claim 1 , wherein at least a portion of the at least two different types of sequence-specific oligonucleotide probes comprises tagged probes.
4. The method of claim 1 , wherein at least a portion of the template or the at least two different types of sequence-specific oligonucleotide probes is coated with a protein.
5. The method of claim 1 , wherein step b) is performed at a temperature ≥a first Tm wherein the first Tm is the melting temperature of the first type of the at least two different types of sequence-specific oligonucleotide probes and the hybridizing step in step f) is performed at a temperature ≥a second Tm, wherein the second Tm is the melting temperature of the second type of the at least two different types of sequence-specific oligonucleotide probes.
6. The method of claim 1 , wherein step c) is conducted at a temperature ≥a first Tm wherein the first Tm is the melting temperature of the first type of the at least two different types of sequence-specific oligonucleotide probes and the base extension reaction in step f) is conducted at a temperature ≥a second Tm wherein the second Tm is the melting temperature of the second type of the at least two different types of sequence-specific oligonucleotide probes.
7. A method for analyzing a biomolecule analyte comprising the steps of:
a) producing the biomolecule analyte using the method of claim 1 ;
b) disposing the biomolecule analyte in a fluidic channel, wherein the fluidic channel is a nanochannel or microchannel;
c) applying a potential along the fluidic channel;
d) translocating the biomolecule analyte from a first end of the fluidic channel to a second end of the fluidic channel; and
e) detecting electrical properties cross the fluidic channel as the biomolecule analyte moves through the fluidic channel, thereby analyzing the biomolecule analyte.