Nucleotide sequence of the gene for bacteriophage T7 RNA polymerase.

Differences between two previously published nucleotide sequences for bacteriophage T7 gene 1 have been resolved. The revised sequence has eight changes from the sequence that was used to compile the complete nucleotide sequence of T7 DNA. The revisions do not change the total number of nucleotides in T7 DNA or the predicted number of amino acids in T7 RNA polymerase. Only one of the changes introduces any change in predicted cleavage sites for known restriction endonucleases, and the correctness of the revised sequence at this position has been confirmed by cutting T7 DNA with the appropriate enzyme. However, the revisions do make a substantial difference in the amino acid sequence predicted for T7 RNA polymerase: 37 of the 883 amino acids are changed, 35 because of a shift in reading frame for one stretch of 37 amino acids. The predicted reading frame through this region now agrees with that predicted for the same region of the homologous T3 RNA polymerase. The calculated molecular weight for T7 RNA polymerase is now 98,856.