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Specificity factor

A specificity factor is an amino acid sequence that mediates target recognition in RNA polymerase. An example is the sigma subunit of the Escherichia coli RNA polymerase holoenzyme which regulates a binding σ subunit of molecular weight 70 kDa. Under some conditions, some of the 70-kDa subunits are replaced by one of the other, more-specific factors. For instance, when bacteria are subjected to heat stress, some of the 70-kDa subunits are replaced by a 32-kDa subunit; when bound to σ32, RNA polymerase is directed to a specialized set of promoters with a different consensus sequence.

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A specificity factor is an amino acid sequence that mediates target recognition in RNA polymerase.1 An example is the sigma subunit of the Escherichia coli RNA polymerase holoenzyme which regulates a binding σ subunit of molecular weight 70 kDa. Under some conditions, some of the 70-kDa subunits are replaced by one of the other, more-specific factors. For instance, when bacteria are subjected to heat stress, some of the 70-kDa subunits are replaced by a 32-kDa subunit; when bound to σ32, RNA polymerase is directed to a specialized set of promoters with a different consensus sequence.

References

References

  1. Jang, Sei Heon; Jaehnings, Judith A. (1991). "The Yeast Mitochondrial RNA Polymerase Specificity Factor, MTF1, Is Similar to Bacterial 0 Factors" (PDF). The Journal of Biological Chemistry. 266 (39): 22671–22677. doi:10.1016/S0021-9258(18)54622-6.