期刊
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
卷 107, 期 20, 页码 9376-9381出版社
NATL ACAD SCIENCES
DOI: 10.1073/pnas.1001188107
关键词
transcription initiation; sigma factors; ATP analogues; DNA melting
资金
- Wellcome Trust [084599/Z/07/Z]
- Biotechnology and Biological Sciences Research Council [BB/G001278/1]
- Biotechnology and Biological Sciences Research Council [BB/G001278/1] Funding Source: researchfish
- BBSRC [BB/G001278/1] Funding Source: UKRI
- Wellcome Trust [084599/Z/07/Z] Funding Source: Wellcome Trust
ATP hydrolysis-dependent molecular machines and motors often drive regulated conformational transformations in cell signaling and gene regulation complexes. Conformational reorganization of a gene regulation complex containing the major variant form of bacterial RNA polymerase (RNAP), E sigma(54), requires engagement with its cognate ATP-hydrolyzing activator protein. Importantly, this activated RNAP is essential for a number of adaptive responses, including those required for bacterial pathogenesis. Here we characterize the initial encounter between the enhancer-dependent E sigma(54) and its cognate activator AAA+ ATPase protein, before ADP+P(i) formation, using a small primed RNA (spRNA) synthesis assay. The results show that in a prehydrolysis state, sufficient activator-dependent rearrangements in E sigma(54) have occurred to allow engagement of the RNAP active site with single-stranded promoter DNA to support spRNA synthesis, but not to melt the promoter DNA. This catalytically competent transcription intermediate has similarity with the open promoter complex, in that the RNAP dynamics required for DNA scrunching should be occurring. Significantly, this work highlights that prehydrolysis states of ATPases are functionally important in the molecular transformations they drive.
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