Abstract
The C-terminal domain of the alpha subunit of the RNA polymerase (alphaCTD) from Escherichia coli (Ec) regulates transcription by interacting with many kinds of proteins and promoter upstream (UP) elements consisting of AT-rich sequences. However, it is unclear how this system is common in all eubacteria. We investigate the structure and properties of alphaCTD from an extremely thermophilic eubacterium, Thermus thermophilus (Tt). The solution structure of Tt alphaCTD (85 amino acids) was determined by NMR, and the interaction between Tt alphaCTD and DNA with different sequences was investigated by means of chemical shift perturbation experiments. The tertiary structure of Tt alphaCTD is almost identical with that of Ec alphaCTD despite 32% sequence homology. However, Tt alphaCTD interacts with the upstream region sequence of the promoter in the Tt 16 S ribosomal protein operon rather than the Ec UP element DNA. The upstream region sequence of Tt is composed of 25 base pairs with 40% AT, unlike the Ec UP element with 80% AT. The DNA binding site in Tt alphaCTD is located on the surface composed of helix 4 and the loop preceding helix 4. The electric charges on this surface are not remarkably localized like those of Ec alphaCTD.
Highlights
The abbreviations used areEscherichia coli; ␣CTD, C-terminal domain of the ␣ subunit of the RNA polymerase; BAF, barrier to autointegration factor; TUP, the upstream region sequence of the promoter in the 16 S ribosomal protein operon of Thermus thermophilus; Tt, Thermus thermophilus; UP, promoter upstream; rsmd, root mean square deviation
It is unclear how these transcription regulation systems are used in all eubacteria
The higher thermal stability of Thermus thermophilus (Tt) ␣CTD was shown by circular dichroic (CD) measurement, and the solution structure of Tt ␣CTD was determined by NMR
Summary
Escherichia coli; ␣CTD, C-terminal domain of the ␣ subunit of the RNA polymerase; BAF, barrier to autointegration factor; TUP, the upstream region sequence of the promoter in the 16 S ribosomal protein operon of Thermus thermophilus; Tt, Thermus thermophilus; UP, promoter upstream; rsmd, root mean square deviation
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call