4X8K

Mycobacterium tuberculosis RbpA-SID in complex with SigmaA domain 2

4X8K の概要

• エントリーDOI: 10.2210/pdb4x8k/pdb
• 分子名称: RNA polymerase sigma factor SigA, RNA polymerase-binding protein RbpA, SULFATE ION, ... (5 entities in total)
• 機能のキーワード: transcription activator, sigma factor
• 由来する生物種: Mycobacterium tuberculosis; 詳細
• 細胞内の位置: Cytoplasm : P9WGI0
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 25642.26

構造登録者

Hubin, E.A.,Flack, J.E.,Tabib-Salazar, A.,Paget, M.S.,Darst, S.A.,Campbell, E.A. (登録日: 2014-12-10, 公開日: 2015-06-03, 最終更新日: 2023-09-27)

主引用文献

Hubin, E.A.,Tabib-Salazar, A.,Humphrey, L.J.,Flack, J.E.,Olinares, P.D.,Darst, S.A.,Campbell, E.A.,Paget, M.S.
Structural, functional, and genetic analyses of the actinobacterial transcription factor RbpA.
Proc.Natl.Acad.Sci.USA, 112:7171-7176, 2015

PubMed Abstract: Gene expression is highly regulated at the step of transcription initiation, and transcription activators play a critical role in this process. RbpA, an actinobacterial transcription activator that is essential in Mycobacterium tuberculosis (Mtb), binds selectively to group 1 and certain group 2 σ-factors. To delineate the molecular mechanism of RbpA, we show that the Mtb RbpA σ-interacting domain (SID) and basic linker are sufficient for transcription activation. We also present the crystal structure of the Mtb RbpA-SID in complex with domain 2 of the housekeeping σ-factor, σ(A). The structure explains the basis of σ-selectivity by RbpA, showing that RbpA interacts with conserved regions of σ(A) as well as the nonconserved region (NCR), which is present only in housekeeping σ-factors. Thus, the structure is the first, to our knowledge, to show a protein interacting with the NCR of a σ-factor. We confirm the basis of selectivity and the observed interactions using mutagenesis and functional studies. In addition, the structure allows for a model of the RbpA-SID in the context of a transcription initiation complex. Unexpectedly, the structural modeling suggests that RbpA contacts the promoter DNA, and we present in vivo and in vitro studies supporting this finding. Our combined data lead to a better understanding of the mechanism of RbpA function as a transcription activator.

PubMed: 26040003
DOI: 10.1073/pnas.1504942112

実験手法

X-RAY DIFFRACTION (2.202 Å)