T7 DNA polymerase
First Claim
1. A purified modified gene encoding a modified bacteriophage T7-type DNA polymerase wherein said polymerase comprises sufficient DNA polymerase activity for use in DNA sequencing when said polymerase is combined with any host factor necessary for said DNA polymerase activity, and wherein said modified gene modified to reduce the activity of naturally-occurring exonuclease activity of the naturally occurring DNA polymerase.
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Abstract
The invention relates to methods of DNA sequencing including a method for determining the nucleotide base sequence of a DNA molecule, comprising providing the DNA molecule annealed with a primer molecule able to hybridize to the DNA molecule, incubating the annealed mixture with a DNA polymerase, except reverse transcriptase, in the presence of four different deoxynucleoside triphosphates and a chain terminating agent which terminates DNA synthesis at a specific nucleotide base, the concentration of all four deoxynucleoside triphosphates at the start of said incubating being sufficient to allow DNA synthesis to continue until terminated by said agent. The DNA products of the incubating reaction are separated according to their size, so that at least a part of the nucleotide base sequence of the DNA molecule can be determined. In a furter embodiment the primer may be extended and labelled prior to the incubating reaction.
43 Citations
27 Claims
- 1. A purified modified gene encoding a modified bacteriophage T7-type DNA polymerase wherein said polymerase comprises sufficient DNA polymerase activity for use in DNA sequencing when said polymerase is combined with any host factor necessary for said DNA polymerase activity, and wherein said modified gene modified to reduce the activity of naturally-occurring exonuclease activity of the naturally occurring DNA polymerase.
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9. A purified modified gene encoding a modified bacteriophage T7-type DNA polymerase wherein said polymerase comprises sufficient DNA polymerase activity for use in DNA sequencing when said polymerase is combined with any host factor necessary for said DNA polymerase activity, and wherein said modified gene results from the modification of a naturally occurring gene modified to eliminate the naturally occurring exonuclease activity of the naturally occurring DNA polymerase.
- 10. A modified gene encoding a modified bacteriphage T7-type DNA polymerase, wherein said polymerase comprises sufficient DNA polymerase activity for use in DNA sequencing when said polymerase is combined with any host factor necessary for said DNA polymerase activity and wherein said modified gene results from the modification of a naturally occurring gene modified to reduce by at least 30% the naturally occurring exonuclease activity of the naturally occurring DNA polymerase.
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19. A purified modified T7-DNA polymerase having sufficient DNA polymerase activity for use in DNA sequencing when said polymerase is combined with any host factor necessary for said DNA polymerase activity, wherein said polymerase, compared to native DNA polymerase, lacks one or more amino acids and thereby has a reduced exonuclease activity.
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20. A purified modified T7-type DNA polymerase having sufficient DNA polymerase activity for use in DNA sequencing when said polymerase is combined with any host factor necessary for said DNA polymerase activity, wherein said polymerase, compared to native DNA polymerase has one or more amino acids substituted by an amino acid other than that naturally occurring at the site of substitution, and thereby has a reduced exonuclease activity.
- 24. A modified gene encoding a processive modified DNA polymerase, wherein said polymerase comprises sufficient DNA polymerase activity for use in DNA sequencing when said polymerase is combined with any host factor necessary for said DNA polymerase activity, and wherein said modified gene results from the modification of a naturally occurring gene modified to reduce the activity of naturally occurring exonuclease activity of the naturally occurring DNA polymerase.
Specification