Intermittent detection during analytical reactions
Methods, devices, and systems for performing intermittent detection during analytical reactions are provided. Such methods facilitate collection of reaction data from disparate reaction times. Further, such methods are useful for reducing photo-induced damage of one or more reactants in an illuminated analytical reaction at a given reaction time. In preferred embodiments, the reaction mixture is subjected to at least one illuminated and non-illuminated period and allowed to proceed such that the time in which the reaction mixture is illuminated is less than a photo-induced damage threshold period.
1. A method of performing an analytical reaction, comprising:
a) preparing a reaction mixture containing components of the analytical reaction, wherein at least one of the components is a detectable component;
b) initiating the analytical reaction in the reaction mixture to begin progression of the analytical reaction, wherein the analytical reaction comprises an enzyme selected from the group consisting of a polymerase, a ligase, a ribosome, a nuclease, and a kinase; and
c) maintaining conditions that allow the analytical reaction to proceed while subjecting the reaction mixture to at least one detection period and at least one non-detection period during the progression of the analytical reaction, wherein the detection period is an illuminated period and the non-detection period is a non-illuminated period, and further wherein the detectable component is present during both said detection period and said non-detection period, thereby performing the analytical reaction.
2. The method of claim 1 , further comprising collecting illumination data during the illuminated period, collecting non-illumination data during the non-illuminated period, and further wherein an optical system is used in collecting the illumination data but is not used in collecting the non-illumination data.
3. The method of claim 1 , wherein the enzyme is a polymerase and the method further comprises pause or stop points to control the activity of the polymerase during the analytical reaction.
4. The method of claim 1 , wherein said subjecting the reaction mixture to at least one detection period and at least one non-detection period during the progression of the analytical reaction results in a change in one or more aspects of the analytical reaction, said aspects selected from the group consisting of processivity, fidelity, rate, and duration.
5. The method of claim 1 , wherein the analytical reaction is a sequencing reaction comprising a single nucleic acid template, wherein the sequencing reaction generates sequence reads during the detection period by detecting the detectable component, and does not generate sequence reads during the non-detection period by suspending detection of the detectable component.
6. The method of claim 5 , wherein the sequencing reaction comprises at least two detection periods and generates a plurality of noncontiguous sequence reads from the single nucleic acid template.
7. The method of claim 6 , wherein the plurality comprises at least three noncontiguous sequence reads.
8. The method of claim 5 , wherein the single nucleic acid template comprises multiple repeat sequences.
9. The method of claim 5 , wherein the sequencing reaction comprises passage of the single nucleic acid template through a nanopore.
10. The method of claim 5 , wherein the sequencing reaction comprises primer extension by a polymerase enzyme and the detectable component is a nucleotide or nucleotide analog.
11. The method of claim 1 , wherein the analytical reaction is a processive reaction.
12. The method of claim 11 , further comprising collecting detection data in real time during the detection period, collecting non-detection data in real time during the non-detection period, and combining the detection data and the non-detection data to characterize the analytical reaction.
13. The method of claim 1 , wherein the detectable component has a detectable label.
14. The method of claim 13 , wherein the detectable label is a luminescent, fluorescent, or fluorogenic label.
15. The method of claim 1 , wherein the detectable component is a labeled nucleotide or nucleotide analog, and further wherein a concentration of the labeled nucleotide or nucleotide analog in the reaction mixture is greater than a concentration of any unlabeled nucleotide or nucleotide analog present in the reaction mixture throughout the progression of the analytical reaction.
16. The method of claim 1 , wherein the detection period and the non-detection period are created without any substitution of components in the analytical reaction during progression of the analytical reaction.
17. The method of claim 1 , wherein a plurality of analytical reactions are characterized, and further wherein the plurality of analytical reactions are disposed on a solid support.
18. A method of generating a plurality of noncontiguous sequence reads from a single nucleic acid template molecule, comprising:
a) preparing a reaction mixture comprising the single template nucleic acid molecule, a polymerase enzyme, and a set of labeled nucleotides or nucleotide analogs, wherein the set comprises at least one type of labeled nucleotide or nucleotide analog for each of the natural nucleobases (A, G, T, and C), and further wherein each type of labeled nucleotide or nucleotide analog in the set comprises a detectable label that distinguishes it from every other type in the set;
b) initiating the polymerization reaction to begin a first processive incorporation of a plurality of the labeled nucleotides or nucleotide analogs into a nascent nucleic acid strand complementary to the single template nucleic acid molecule;
c) detecting the first processive incorporation by optical means, thereby generating one of the plurality of noncontiguous sequence reads from the single template nucleic acid template molecule;
d) performing a buffer exchange to substitute the labeled nucleotides or nucleotide analogs with unlabeled nucleotides or nucleotide analogs;
e) allowing the polymerization reaction to begin a second processive incorporation of the unlabeled nucleotides or nucleotide analogs without detecting the second processive incorporation of the unlabeled nucleotides or nucleotide analogs;
f) performing a buffer exchange to substitute the unlabeled nucleotides or nucleotide analogs with the labeled nucleotides or nucleotide analogs;
g) allowing the polymerization reaction to initiate a third processive incorporation of a plurality of the labeled nucleotides or nucleotide analogs; and
h) detecting the third processive incorporation by optical means, thereby generating a second of the plurality of noncontiguous sequence reads from the single template nucleic acid molecule.
19. The method of claim 18 further comprising repeating steps d-g, wherein steps d-g are repeated n times to generate (n+2) noncontiguous sequence reads.