Patent application number | Description | Published |
20090286245 | TWO SLOW-STEP POLYMERASE ENZYME SYSTEMS AND METHODS - Compositions, kits, methods and systems for nucleotide sequencing comprising producing polymerase reactions that exhibit two kinetically observable steps within an observable phase of the polymerase reaction. Two slow step systems can be produced, for example, by selecting the appropriate polymerase enzyme, polymerase reaction conditions including cofactors, and polymerase reaction substrates including the primed template and nucleotides. | 11-19-2009 |
20100112645 | Generation of modified polymerases for improved accuracy in single molecule sequencing - Provided are compositions comprising modified recombinant polymerases that exhibit branching fractions that are less than the branching fractions of the polymerases from which they were derived, or branching fractions that are less than about 25% for a phosphate-labeled nucleotide analog. Also provided are compositions comprising modified recombinant polymerases that exhibit closed polymerase/DNA complexes with increased stability relative to the parental polymerases. Also provided are compositions comprising modified recombinant polymerases that exhibit decreased rate constants relative to the parental polymerases. Provided are methods for generating polymerases with the aforementioned phenotypes. Provided are methods of using such polymerases to make a DNA or to sequence a DNA template. | 05-06-2010 |
20100221716 | Classification of Nucleic Acid Templates - Methods, compositions, and systems are provided for characterization of modified nucleic acids. In certain preferred embodiments, single molecule sequencing methods are provided for identification of modified nucleotides within nucleic acid sequences. Modifications detectable by the methods provided herein include chemically modified bases, enzymatically modified bases, abasic sites, non-natural bases, secondary structures, and agents bound to a template nucleic acid. | 09-02-2010 |
20110160077 | SEQUENCING METHODS USING ENZYME CONFORMATION - Systems and methods are provided for single-molecule sequencing of template nucleic acids in which the signal from a label attached to a polymerase enzyme is used to monitor conformational changes in the polymerase which occur while labeled nucleotides or nucleotide analogs are added to a growing nucleic acid chain which is complementary to the template nucleic acid. The signal indicative of the conformational state of the enzyme is used to determine with higher confidence when true nucleotide or nucleotide analog incorporation events occur, allowing for the improved quality of base calls and sequence determination. | 06-30-2011 |
20110183320 | CLASSIFICATION OF NUCLEIC ACID TEMPLATES - Methods, compositions, and systems are provided for characterization of modified nucleic acids. In certain preferred embodiments, single molecule sequencing methods are provided for identification of modified nucleotides within nucleic acid sequences. Modifications detectable by the methods provided herein include chemically modified bases, enzymatically modified bases, abasic sites, non-natural bases, secondary structures, and agents bound to a template nucleic acid. | 07-28-2011 |
20110189659 | Generation of modified polymerases for improved accuracy in single molecule sequencing - Provided are compositions comprising recombinant DNA polymerases that include amino acid substitutions, insertions, deletions and/or heterologous or exogenous features that confer modified properties upon the polymerase for enhanced single molecule sequencing. Such properties can include reduced reaction rates at one or more steps of the polymerase kinetic cycle, increased closed polymerase/DNA complex stability, enhanced metal ion coordination, reduced exonuclease activity, decreased branching fractions, and the like. Polymerases that exhibit branching fractions that are less than the branching fractions of the polymerases from which they were derived, or branching fractions that are less than about 25% for a phosphate-labeled nucleotide analog, are also provided. Also provided are nucleic acids which encode the polymerases with the aforementioned phenotypes, as well as methods of using such polymerases to make a DNA or to sequence a DNA template. | 08-04-2011 |
20110212437 | SINGLE MOLECULE SEQUENCING WITH TWO DISTINCT CHEMISTRY STEPS - Methods, Compositions, and Systems are provided for nucleic acid sequencing where the sequential incorporation of nucleotides uses two distinct chemical steps. A plurality of nucleotide analogs, each having a labeled leaving group at its 3′ hydroxyl can be sequentially added to a growing strand in the presence of a selective cleaving activity that cleaves the 3′ hydroxyl leaving group preferentially after it has been incorporated. The selective cleaving agent can comprise an exonuclease activity, and the exonuclease activity can be a polymerase-associated exonuclease activity. Nucleotide analogs having labels on both a cleavable polyphosphate portion and on a 3′ hydroxyl leaving group can provide signals characteristic of nucleotide analog incorporation. Systems having illumination optics, collection optics, and substrates observe signals from the labels as they are being incorporated into a growing nucleic acid strand, allowing for the sequencing of template nucleic acids. | 09-01-2011 |
20120034602 | Recombinant Polymerases For Improved Single Molecule Sequencing - Provided are compositions comprising recombinant DNA polymerases that include amino acid substitutions, insertions, deletions, and/or exogenous features that confer modified properties upon the polymerase for enhanced single molecule sequencing. Such properties can include enhanced metal ion coordination, reduced exonuclease activity, reduced reaction rates at one or more steps of the polymerase kinetic cycle, decreased branching fraction, altered cofactor selectivity, increased yield, increased thermostability, increased accuracy, increased speed, increased readlength, and the like. Also provided are nucleic acids which encode the polymerases with the aforementioned phenotypes, as well as methods of using such polymerases to make a DNA or to sequence a DNA template. | 02-09-2012 |