The transcription initiation pathway of sigma 54 mutants that bypass the enhancer protein requirement. Implications for the mechanism of activation.

The Journal of Biological Chemistry
J T Wang, J D Gralla

Abstract

In vitro transcription, DNase I footprinting, and abortive initiation assays were used to characterize transcription using mutant forms of sigma 54 shown previously to bypass certain enhancer requirements in vitro. The holoenzymes containing these sigma mutants produce low levels of open complexes at both the glnAp2 and glnHp2 promoters. The open complexes are unusual in that they are destroyed by heparin. Enhancer protein and ATP convert them into a stable heparin-resistant state. The enhancer response occurs over a similar range of NtrC concentration as occurs with the wild-type holoenzyme, indicating that the activation determinants have been largely preserved within these mutants. One-round transcription assays show that the mutant holoenzymes can be driven to transcribe both promoters without NtrC. The unstable opening induced by these mutations apparently serves as a conduit that can shuttle templates into transcriptionally competent complexes. The results lead to a model in which activation occurs in two steps. First, the enhancer complex overcomes an inhibitory effect of the sigma 54 leucine patch and unlocks the melting activity of the holoenzyme. Second, different sigma 54 determinants are used to drive stabilization ...Continue Reading

References

Oct 20, 1992·Journal of Molecular Biology·F Claverie-Martin, B Magasanik
Nov 1, 1991·Trends in Biochemical Sciences·S KustuD S Weiss
Jan 1, 1991·Methods in Enzymology·S Sasse-Dwight, J D Gralla
Sep 1, 1991·Microbiological Reviews·J Collado-VidesJ D Gralla
Mar 1, 1991·Proceedings of the National Academy of Sciences of the United States of America·F Claverie-Martin, B Magasanik
Jul 1, 1990·Proceedings of the National Academy of Sciences of the United States of America·W SuH Echols
Dec 1, 1985·Proceedings of the National Academy of Sciences of the United States of America·T P Hunt, B Magasanik
Dec 1, 1988·Proceedings of the National Academy of Sciences of the United States of America·S Sasse-Dwight, J D Gralla
Jan 1, 1988·Annual Review of Biochemistry·J D Helmann, M J Chamberlin
Nov 1, 1980·Proceedings of the National Academy of Sciences of the United States of America·D K Hawley, W R McClure
Sep 15, 1995·Genes & Development·Y TintutJ D Gralla
Jan 1, 1993·Journal of Cellular Biochemistry·B Magasanik

❮ Previous
Next ❯

Citations

May 3, 2000·Molecular Microbiology·J C BoucherV Deretic
Jun 6, 1998·Proceedings of the National Academy of Sciences of the United States of America·D A Rowe-Magnus, G B Spiegelman
Feb 27, 2001·Nucleic Acids Research·S R WigneshwerarajM Buck
Jul 14, 2000·Journal of Bacteriology·M BuckJ D Gralla
Sep 2, 1997·Proceedings of the National Academy of Sciences of the United States of America·J T WangJ D Gralla
Nov 17, 2007·Journal of Molecular Biology·Patricia C BurrowsMartin Buck
Mar 14, 1997·Science·E P Geiduschek
Jun 18, 2015·Nucleic Acids Research·Jorrit SchaeferMartin Buck
Aug 28, 1999·The Journal of Biological Chemistry·M T GallegosM Buck
Oct 19, 2000·The Journal of Biological Chemistry·W CannonM Buck
Nov 9, 2002·The Journal of Biological Chemistry·Siva R WigneshwerarajMartin Buck
Feb 23, 2017·Proceedings of the National Academy of Sciences of the United States of America·Elizabeth A CampbellSeth A Darst
Jan 24, 1998·The Journal of Biological Chemistry·B S Wolner, J D Gralla
May 21, 2020·Frontiers in Microbiology·Morgan A AlfordRobert E W Hancock
Oct 29, 1998·Journal of Bacteriology·L Wang, J D Gralla

❮ Previous
Next ❯

Related Concepts

Related Feeds

ASBMB Publications

The American Society for Biochemistry and Molecular Biology (ASBMB) includes the Journal of Biological Chemistry, Molecular & Cellular Proteomics, and the Journal of Lipid Research. Discover the latest research from ASBMB here.