Photocleavable labeled nucleotides and nucleosides and methods for their use in DNA sequencing
Provided are novel nucleotides, nucleoside, and their derivatives described herein, that can be used in DNA sequencing technology and other types of DNA analysis. In one embodiment, the nucleotide or nucleoside with an unprotected 3′-OH group is derivatized at the nucleobase to include a fluorescent dye attached via a linker to a photocleavable terminating group. The photocleavable-fluorescent group is designed to terminate DNA synthesis as well as be cleaved so that DNA oligomers can be sequenced efficiently in a parallel format. The design of such rapidly cleavable fluorescent groups on nucleotides and nucleosides can enhance the speed and accuracy of sequencing of large oligomers of DNA in parallel, to allow rapid whole genome sequencing, and the identification of polymorphisms and other valuable genetic information, as well as allowing further manipulation and analysis of nucleic acid molecules in their native state following cleavage of the fluorescent group.
1. A compound according to the following formula or a salt thereof:
wherein R 1 is H, monophosphate, diphosphate, triphosphate, or alpha thiotriphosphate;
R 2 is H or OH;
the Base is cytosine, uracil, thymine, adenine, guanine, or naturally occurring derivatives thereof;
the Cleavable terminating moiety-Linker-Dye is a group of the formula:
wherein
R 3 and R 4 are each independently H, a C 1 -C 12 straight chain or branched alkyl, a C 2 -C 12 straight chain or branched alkenyl or polyenyl, a C 2 -C 12 straight chain or branched alkynyl or polyalkynyl, or an aromatic group, with the proviso that at least one of R 3 and R 4 is H;
R 5 , R 6 , R 7 and R 8 are each independently H, OCH 3 , NO 2 , CN, a halide, a C 1 -C 12 straight chain or branched alkyl, a C 2 -C 12 straight chain or branched alkenyl or polyenyl, a C 2 -C 12 straight chain or branched alkynyl or polyalkynyl, an aromatic group, or the Linker-Dye group, with the proviso that at least one of R 5 , R 6 , R 7 , and R 8 is the Linker-Dye group;
the Cleavable terminating moiety imparts polymerase termination properties to the compound and is attached to the Base by a direct bond or a linkage group;
the Linker and the linkage group are, independently, a bifunctional group; and
the Dye is a fluorophore.
2. A compound according to claim 1 , wherein the linkage group is selected from —OCH 2 —, —OC(O)—, —O—, —CH 2 C(O)—, —OC(O)OCH 2 —, and —CH 2 OC(O) —.
3. A compound according to claim 1 , wherein the compound is a formula or salt thereof selected from the group consisting of:
wherein R 1 is H, monophosphate, diphosphate, triphosphate, or alphathiotriphosphate,
R 2 is H or OH,
R 3 and R 4 are each independently H or a C 1 -C 12 straight chain or branched alkyl, with the proviso that at least one of R 3 and R 4 is H,
R 5 , R 7 , and R 8 are each independently selected from the group consisting of H, OCH 3 , NO 2 , CN, a halide, and a C 1 -C 12 straight chain or branched alkyl, and
R 6 is the Linker-Dye group, which is further defined as:
wherein X is C≡C, and
Dye is a fluorophore.
4. A compound according to claim 3 , wherein R 3 and R 4 are selected from the group consisting of —CH 3 , —CH 2 CH 3 , —CH 2 CH 2 CH 3 , isopropyl, and tert-butyl.
5. A compound-according to claim 3 , wherein the compound is selected from the group consisting of
6. The compound of claim 1 , wherein the compound is able to terminate a polymerase reaction at an efficiency between about 70% to about 100%.
7. The compound of claim 6 , wherein the compound is able to terminate a polymerase reaction at an efficiency between about 90% to about 100%.