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Conformational flexibility of sigma(70) in anti-terminator loading
Pieter L DeHaseth1, Jonatha M Gott
1RNA Center, Case Western Reserve University, Cleveland, OH 44106-4973, USA. pieter.dehaseth@case.edu
Molecular Microbiology
|December 23, 2009
Summary
Researchers found that the sigma(70) protein
Area of Science:
- Molecular Microbiology
- Biochemistry
- Genetics
Background:
- The sigma(70) subunit of bacterial RNA polymerase is crucial for promoter recognition.
- Optimal DNA binding typically requires a 17 bp spacing between promoter -10 and -35 elements for sigma(70) interaction.
- The C-terminal domain of sigma(70), including the 3.2 linker, plays a role in this interaction.
Discussion:
- Devi et al. show that without the C-terminal domain of sigma(70), shorter DNA spacings (0-3 bp) between promoter elements are tolerated.
- This highlights the significant flexibility of the sigma(70) 3.2 linker region.
- The ability to accommodate varied distances suggests a dynamic interaction mechanism.
Key Insights:
- The sigma(70) 3.2 linker's flexibility allows for non-canonical DNA spacing in promoter recognition.
- A stable complex formed with a 2 bp separation is identified.
- This finding challenges previous assumptions about fixed spacing requirements.
Outlook:
- The stable 2 bp complex offers a potential model for structural studies of early elongation complexes.
- Further research can explore the structural basis of the 3.2 linker's flexibility.
- Understanding this flexibility may reveal new regulatory mechanisms in transcription initiation.
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