Structure and function of CarD, an essential mycobacterial transcription factor Academic Article uri icon


MeSH Major

  • Bacterial Proteins
  • DNA, Bacterial
  • Mycobacterium tuberculosis
  • Promoter Regions, Genetic
  • Transcription Factors


  • CarD, an essential transcription regulator in Mycobacterium tuberculosis, directly interacts with the RNA polymerase (RNAP). We used a combination of in vivo and in vitro approaches to establish that CarD is a global regulator that stimulates the formation of RNAP-holoenzyme open promoter (RPo) complexes. We determined the X-ray crystal structure of Thermus thermophilus CarD, allowing us to generate a structural model of the CarD/RPo complex. On the basis of our structural and functional analyses, we propose that CarD functions by forming protein/protein and protein/DNA interactions that bridge the RNAP to the promoter DNA. CarD appears poised to interact with a DNA structure uniquely presented by the RPo: the splayed minor groove at the double-stranded/single-stranded DNA junction at the upstream edge of the transcription bubble. Thus, CarD uses an unusual mechanism for regulating transcription, sensing the DNA conformation where transcription bubble formation initiates.

publication date

  • July 30, 2013



  • Academic Article



  • eng

PubMed Central ID

  • PMC3732983

Digital Object Identifier (DOI)

  • 10.1073/pnas.1308270110

PubMed ID

  • 23858468

Additional Document Info

start page

  • 12619

end page

  • 24


  • 110


  • 31