5WH1

Apo form of the C-terminal region of human Transcription Factor IIB

5WH1 の概要

• エントリーDOI: 10.2210/pdb5wh1/pdb
• 分子名称: Transcription initiation factor IIB, SULFATE ION (2 entities in total)
• 機能のキーワード: transcription
• 由来する生物種: Homo sapiens (Human)
• 細胞内の位置: Nucleus: Q00403
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 96511.05

構造登録者

Bratkowski, M.A.,Liu, X. (登録日: 2017-07-14, 公開日: 2017-11-29, 最終更新日: 2023-10-04)

主引用文献

Bratkowski, M.,Unarta, I.C.,Zhu, L.,Shubbar, M.,Huang, X.,Liu, X.
Structural dissection of an interaction between transcription initiation and termination factors implicated in promoter-terminator cross-talk.
J. Biol. Chem., 293:1651-1665, 2018

PubMed Abstract: Functional cross-talk between the promoter and terminator of a gene has long been noted. Promoters and terminators are juxtaposed to form gene loops in several organisms, and gene looping is thought to be involved in transcriptional regulation. The general transcription factor IIB (TFIIB) and the C-terminal domain phosphatase Ssu72, essential factors of the transcription preinitiation complex and the mRNA processing and polyadenylation complex, respectively, are important for gene loop formation. TFIIB and Ssu72 interact both genetically and physically, but the molecular basis of this interaction is not known. Here we present a crystal structure of the core domain of TFIIB in two new conformations that differ in the relative distance and orientation of the two cyclin-like domains. The observed extraordinary conformational plasticity may underlie the binding of TFIIB to multiple transcription factors and promoter DNAs that occurs in distinct stages of transcription, including initiation, reinitiation, and gene looping. We mapped the binding interface of the TFIIB-Ssu72 complex using a series of systematic, structure-guided binding and site-specific photocross-linking assays. Our results indicate that Ssu72 competes with acidic activators for TFIIB binding and that Ssu72 disrupts an intramolecular TFIIB complex known to impede transcription initiation. We also show that the TFIIB-binding site on Ssu72 overlaps with the binding site of symplekin, a component of the mRNA processing and polyadenylation complex. We propose a hand-off model in which Ssu72 mediates a conformational transition in TFIIB, accounting for the role of Ssu72 in transcription reinitiation, gene looping, and promoter-terminator cross-talk.

PubMed: 29158257
DOI: 10.1074/jbc.M117.811521

実験手法

X-RAY DIFFRACTION (3.39 Å)