@article{2387,
  keywords = {Escherichia coli, Transcription, Genetic, Transcription Factors, Binding Sites, DNA, Substrate Specificity, Escherichia coli Proteins, Mutagenesis, Transcriptional Elongation Factors, DNA-Directed RNA Polymerases, Base Pairing, RNA, Bacterial, Templates, Genetic},
  author = {Joshua Shaevitz and Elio Abbondanzieri and Robert Landick and Steven Block},
  title = {Backtracking by single RNA polymerase molecules observed at near-base-pair resolution.},
  abstract = {<p>Escherichia coli RNA polymerase (RNAP) synthesizes RNA with remarkable fidelity in vivo. Its low error rate may be achieved by means of a {\textquoteright}proofreading{\textquoteright} mechanism comprised of two sequential events. The first event (backtracking) involves a transcriptionally upstream motion of RNAP through several base pairs, which carries the 3{\textquoteright} end of the nascent RNA transcript away from the enzyme active site. The second event (endonucleolytic cleavage) occurs after a variable delay and results in the scission and release of the most recently incorporated ribonucleotides, freeing up the active site. Here, by combining ultrastable optical trapping apparatus with a novel two-bead assay to monitor transcriptional elongation with near-base-pair precision, we observed backtracking and recovery by single molecules of RNAP. Backtracking events ( approximately 5 bp) occurred infrequently at locations throughout the DNA template and were associated with pauses lasting 20 s to >30 min. Inosine triphosphate increased the frequency of backtracking pauses, whereas the accessory proteins GreA and GreB, which stimulate the cleavage of nascent RNA, decreased the duration of such pauses.</p>},
  year = {2003},
  journal = {Nature},
  volume = {426},
  pages = {684-7},
  month = {12/2003},
  language = {eng},
}