TFIID-based PIC-Mediator holo-complex in fully-assembled state (hPIC-MED)TFIID-based PIC-Mediator holo-complex in fully-assembled state (hPIC-MED)

Structural highlights

7enc is a 10 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:Electron Microscopy, Resolution 4.13Å
Ligands:,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Publication Abstract from PubMed

The 1.3-megadalton transcription factor IID (TFIID) is required for preinitiation complex (PIC) assembly and RNA polymerase II (Pol II)-mediated transcription initiation on almost all genes. The 26-subunit Mediator stimulates transcription and cyclin-dependent kinase 7 (CDK7)-mediated phosphorylation of the Pol II C-terminal domain (CTD). We determined the structures of human Mediator in the Tail module-extended (at near-atomic resolution) and Tail-bent conformations and structures of TFIID-based PIC-Mediator (76 polypeptides, ~4.1 megadaltons) in four distinct conformations. PIC-Mediator assembly induces concerted reorganization (Head-tilting and Middle-down) of Mediator and creates a Head-Middle sandwich, which stabilizes two CTD segments and brings CTD to CDK7 for phosphorylation; this suggests a CTD-gating mechanism favorable for phosphorylation. The TFIID-based PIC architecture modulates Mediator organization and TFIIH stabilization, underscoring the importance of TFIID in orchestrating PIC-Mediator assembly.

Structures of the human Mediator and Mediator-bound preinitiation complex.,Chen X, Yin X, Li J, Wu Z, Qi Y, Wang X, Liu W, Xu Y Science. 2021 Jun 4;372(6546):eabg0635. doi: 10.1126/science.abg0635. Epub 2021 , May 6. PMID:33958484[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. Chen X, Yin X, Li J, Wu Z, Qi Y, Wang X, Liu W, Xu Y. Structures of the human Mediator and Mediator-bound preinitiation complex. Science. 2021 Jun 4;372(6546):eabg0635. PMID:33958484 doi:10.1126/science.abg0635

7enc, resolution 4.13Å

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