Unusual Oligomerization Required for Activity of NtrC, a Bacterial Enhancer-Binding Protein
10.1126/science.275.5306.1658
Crossref journal-article
American Association for the Advancement of Science (AAAS)
Science (221)
Abstract

Nitrogen regulatory protein C (NtrC) contacts a bacterial RNA polymerase from distant enhancers by means of DNA loops and activates transcription by allowing polymerase to gain access to the template DNA strand. It was shown that NtrC from Salmonella typhimurium must build large oligomers to activate transcription. In contrast to eukaryotic enhancer-binding proteins, most of which must bind directly to DNA, some NtrC dimers were bound solely by protein-protein interactions. NtrC oligomers were visualized with scanning force microscopy. Evidence of their functional importance was provided by showing that some inactive non-DNA-binding and DNA-binding mutant forms of NtrC can cooperate to activate transcription.

Bibliography

Wyman, C., Rombel, I., North, A. K., Bustamante, C., & Kustu, S. (1997). Unusual Oligomerization Required for Activity of NtrC, a Bacterial Enhancer-Binding Protein. Science, 275(5306), 1658–1661.

Authors 5
  1. Claire Wyman (first)
  2. Irene Rombel (additional)
  3. Anne K. North (additional)
  4. Carlos Bustamante (additional)
  5. Sydney Kustu (additional)
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  40. The template was plasmid pJES534 (7) which carries the strong enhancer ≈450 bp upstream of the glnA promoter. Unless otherwise noted conditions were chosen to minimize subunit exchange between NtrC dimers. The non-DNA-binding form was phosphorylated before being added to the other components (18). Carbamoyl phosphate was at 10 mM and the final concentrations of σ 54 [purified from S. typhimurium as described (19)] and core RNA polymerase (from Escherichia coli ; kindly supplied by D. Hager and R. Burgess University of Wisconsin Madison) were 50 and 30 nM respectively. Complete subunit mixing between homodimeric species of NtrC for control experiments was achieved as described (3 7).
  41. Supported by NIH grants GM17078 (C.W. and the late Harrison Echols) GM32543 (C.B.) and GM38361 (S.K). We thank K. Yamamoto for advice on eukaryotic transcriptional activation and R. Chambers and N. Pace for criticism of the manuscript.
Dates
Type When
Created 23 years, 1 month ago (July 27, 2002, 5:45 a.m.)
Deposited 1 year, 7 months ago (Jan. 12, 2024, 10:56 p.m.)
Indexed 3 weeks, 6 days ago (Aug. 6, 2025, 9:02 a.m.)
Issued 28 years, 5 months ago (March 14, 1997)
Published 28 years, 5 months ago (March 14, 1997)
Published Print 28 years, 5 months ago (March 14, 1997)
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@article{Wyman_1997, title={Unusual Oligomerization Required for Activity of NtrC, a Bacterial Enhancer-Binding Protein}, volume={275}, ISSN={1095-9203}, url={http://dx.doi.org/10.1126/science.275.5306.1658}, DOI={10.1126/science.275.5306.1658}, number={5306}, journal={Science}, publisher={American Association for the Advancement of Science (AAAS)}, author={Wyman, Claire and Rombel, Irene and North, Anne K. and Bustamante, Carlos and Kustu, Sydney}, year={1997}, month=mar, pages={1658–1661} }