In this section
@article{Jovanovic:2011:10.1074/jbc.M110.212902,
author = {Jovanovic, M and Burrows, PC and Bose, D and Camara, B and Wiesler, S and Zhang, X and Wigneshweraraj, S and Weinzierl, RO and Buck, M},
doi = {10.1074/jbc.M110.212902},
journal = {J Biol Chem},
pages = {14469--14479},
title = {Activity map of the Escherichia coli RNA polymerase bridge helix},
url = {http://dx.doi.org/10.1074/jbc.M110.212902},
volume = {286},
year = {2011}
}
TY - JOUR
AB - Transcription, the synthesis of RNA from a DNA template, is performed by multisubunit RNA polymerases (RNAPs) in all cellular organisms. The bridge helix (BH) is a distinct feature of all multisubunit RNAPs and makes direct interactions with several active site-associated mobile features implicated in the nucleotide addition cycle and RNA and DNA binding. Because the BH has been captured in both kinked and straight conformations in different crystals structures of RNAP, recently supported by molecular dynamics studies, it has been proposed that cycling between these conformations is an integral part of the nucleotide addition cycle. To further evaluate the role of the BH, we conducted systematic alanine scanning mutagenesis of the Escherichia coli RNAP BH to determine its contributions to activities required for transcription. Combining our data with an atomic model of E. coli RNAP, we suggest that alterations in the interactions between the BH and (i) the trigger loop, (ii) fork loop 2, and (iii) switch 2 can help explain the observed changes in RNAP functionality associated with some of the BH variants. Additionally, we show that extensive defects in E. coli RNAP functionality depend upon a single previously not studied lysine residue (Lys-781) that is strictly conserved in all bacteria. It appears that direct interactions made by the BH with other conserved features of RNAP are lost in some of the E. coli alanine substitution variants, which we infer results in conformational changes in RNAP that modify RNAP functionality.
AU - Jovanovic,M
AU - Burrows,PC
AU - Bose,D
AU - Camara,B
AU - Wiesler,S
AU - Zhang,X
AU - Wigneshweraraj,S
AU - Weinzierl,RO
AU - Buck,M
DO - 10.1074/jbc.M110.212902
EP - 14479
PY - 2011///
SN - 1083-351X
SP - 14469
TI - Activity map of the Escherichia coli RNA polymerase bridge helix
T2 - J Biol Chem
UR - http://dx.doi.org/10.1074/jbc.M110.212902
UR - http://www.ncbi.nlm.nih.gov/pubmed/21357417
VL - 286
ER -
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