Regulation through the secondary channel - Structural framework for ppGpp-DksA synergism during transcription

Anna Perederina, Vladimir Svetlov, Marina N. Vassylyeva, Tahir H. Tahirov, Shigeyuki Yokoyama, Irina Artsimovitch, Dmitry G. Vassylyev

Research output: Contribution to journalArticlepeer-review

253 Scopus citations

Abstract

Bacterial transcription is regulated by the alarmone ppGpp, which binds near the catalytic site of RNA polymerase (RNAP) and modulates its activity. We show that the DksA protein is a crucial component of ppGpp-dependent regulation. The 2.0 Å resolution structure of Escherichia coli DksA reveals a globular domain and a coiled coil with two highly conserved Asp residues at its tip that is reminiscent of the transcript cleavage factor GreA. This structural similarity suggests that DksA coiled coil protrudes into the RNAP secondary channel to coordinate a ppGpp bound Mg2+ ion with the Asp residues, thereby stabilizing the ppGpp-RNAP complex. Biochemical analysis demonstrates that DksA affects transcript elongation, albeit differently from GreA; augments ppGpp effects on initiation; and binds directly to RNAP, positioning the Asp residues near the active site. Substitution of these residues eliminates the synergy between DksA and ppGpp. Thus, the secondary channel emerges as a common regulatory entrance for transcription factors.

Original languageEnglish (US)
Pages (from-to)297-309
Number of pages13
JournalCell
Volume118
Issue number3
DOIs
StatePublished - Aug 6 2004

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

Fingerprint Dive into the research topics of 'Regulation through the secondary channel - Structural framework for ppGpp-DksA synergism during transcription'. Together they form a unique fingerprint.

Cite this