Principal transcription sigma factors of Pseudomonas putida strains mt-2 and G1 are significantly different.

The rpoD gene coding for the primary transcription sigma factor, sigma70, and its entire operon were cloned from strain mt-2 of the purple soil bacterium Pseudomonas putida. Comparison of the deduced amino acid sequence of Ppmt-2 sigma70 with that of sigma70 from P. putida strain G1 shows that the two proteins differ in their primary structure, molecular weight, and isoelectric point. The significance of this difference is discussed in terms of bacterial taxonomy and transcription regulation.