A RNA polymerase with transcriptional activity at 0 degrees C from the Antarctic bacterium Pseudomonas syringae

A DNA-dependent RNA polymerase was purified from the Antarctic psychrotroph ic bacterium Pseudomonas syringae. The RNA polymerase showed a typical euba cterial subunit composition with beta, beta', alpha(2) and sigma subunits. The subunits cross-reacted with antibodies raised against holoenzyme and th e individual subunits of the RNA polymerase of Escherichia coli. However, t he enzyme was considered unique, since unlike the RNA polymerase of mesophi lic E, coli it exhibited significant and consistent transcriptional activit y (10-15%) even at 0 degrees C. But, similar to the enzyme from the mesophi lic bacterium, the RNA polymerase from P. syringae exhibited optimum activi ty at 37 degrees C. The study also demonstrates that the RNA polymerase of P. syringae could preferentially transcribe the cold-inducible gene cspA of E. coli only at lower temperatures (0-22 degrees C). The polymerase was al so observed to be relatively more rifampicin-resistant during transcription at lower temperature. (C) 1999 Federation of European Biochemical Societie s.