Picocalorimetry of transcription by RNA polymerase

Elio A. Abbondanzieri, Joshua W. Shaevitz, Steven M. Block

Research output: Contribution to journalArticlepeer-review

49 Scopus citations


Thermal variations can exert dramatic effects on the rates of enzymes. The influence of temperature on RNA polymerase is of particular interest because its transcriptional activity governs general levels of gene expression, and may therefore exhibit pleiotropic effects in cells. Using a custom-modified optical trapping apparatus, we used a tightly focused infrared laser to heat single molecules of Escherichia coli RNA polymerase while monitoring transcriptional activity. We found a significant change in rates of transcript elongation with temperature, consistent with a large enthalpic barrier to the condensation reaction associated with RNA polymerization (-13 kcal/mol). In contrast, we found little change in either the frequency or the lifetime of off-pathway, paused states, indicating that the energetic barrier to transcriptional pausing is predominantly entropic.

Original languageEnglish (US)
Pages (from-to)L61-L63
JournalBiophysical Journal
Issue number6
StatePublished - Dec 2005
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biophysics


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