Patent ID: 7595180

Claim:
A T7 RNA polymerase, capable of transcribing, under the control of a promoter, a polynucleotide target of interest of a sequence contained in a polynucleotide template, by synthesizing, in the presence of said template and in the absence of associated protein factor and in the absence of a ligase activity, a product of transcription containing an RNA sequence complementary to said sequence, wherein said RNA polymerase (1) is capable of synthesizing said product of transcription with a better yield when said target sequence of said template consists of RNA than when it consists of DNA and (2) is from a family of RNA polymerases whose promoters have a consensus sequence from position −17 to position −1, wherein said T7 RNA polymerase is mutated, such that said mutation consists of an alanine (A) in place of an arginine (R) at position 627 of the T7 RNA polymerase amino acid sequence set forth in SEQ ID NO:14.