Mutated T7 RNA Polymerases
The present invention pertains to a mutated T7 RNA polymerase and its use, the T7 RNA polymerase being mutated at position 744, the glutamine (Q) being replaced by an amino acid selected from arginine (Q744R), leucine (Q744L) or proline (Q744P).
1. A T7 RNA polymerase comprising the amino acid sequence of SEQ ID NO: 16 that is mutated at position 744, wherein the glutamine (Q) at position 744 is replaced by an amino acid selected from arginine (Q744R), leucine (Q744L) or proline (Q744P).
2. The RNA polymerase of claim 1 comprising the mutation Q744R.
3. The RNA polymerase of claim 1 comprising the mutations F849I, F880Y and S430P.
4. The RNA polymerase of claim 3 comprising the mutation C510R.
5. The RNA polymerase of claim 3 comprising the mutation S767G.
6. A gene coding the T7 RNA polymerase of claim 1 .
7. An expression vector comprising the gene of claim 6 and the appropriate expression sequences.
8. A cell transformed with the vector of claim 7 , and capable of expressing mutated RNA polymerase.
9. A method for amplifying nucleic acids, the method comprising the step of using the RNA polymerase of claim 1 in a transcription amplification reaction of nucleic acids.
10. The method of claim 9 , wherein said transcription amplification reaction of nucleic acids is an isothermal transcription amplification reaction of nucleic acids.
11. A mixture of enzymes used in an isothermal transcription amplification reaction comprising:
the RNA polymerase of claim 1 ; and
an enzyme having a reverse transcriptase activity.
12. The mixture of enzymes of claim 11 , said enzyme having a reverse transcriptase activity also having an RNAse H activity.