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Role for the MED21-MED7 Hinge in Assembly of the Mediator-RNA Polymerase II Holoenzyme.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2016 Dec 23; Vol. 291 (52), pp. 26886-26898. Date of Electronic Publication: 2016 Nov 07. - Publication Year :
- 2016
-
Abstract
- Mediator plays an integral role in activation of RNA polymerase II (Pol II) transcription. A key step in activation is binding of Mediator to Pol II to form the Mediator-Pol II holoenzyme. Here, we exploit a combination of biochemistry and macromolecular EM to investigate holoenzyme assembly. We identify a subset of human Mediator head module subunits that bind Pol II independent of other subunits and thus probably contribute to a major Pol II binding site. In addition, we show that binding of human Mediator to Pol II depends on the integrity of a conserved "hinge" in the middle module MED21-MED7 heterodimer. Point mutations in the hinge region leave core Mediator intact but lead to increased disorder of the middle module and markedly reduced affinity for Pol II. These findings highlight the importance of Mediator conformation for holoenzyme assembly.<br /> (© 2016 by The American Society for Biochemistry and Molecular Biology, Inc.)
- Subjects :
- Amino Acid Sequence
Binding Sites
Crystallography, X-Ray
Holoenzymes chemistry
Holoenzymes genetics
Humans
Mediator Complex chemistry
Mediator Complex genetics
Protein Binding
Protein Conformation
RNA Polymerase II chemistry
RNA Polymerase II genetics
Saccharomyces cerevisiae metabolism
Saccharomyces cerevisiae Proteins chemistry
Saccharomyces cerevisiae Proteins genetics
Sequence Homology, Amino Acid
Transcription, Genetic
Holoenzymes metabolism
Mediator Complex metabolism
RNA Polymerase II metabolism
Saccharomyces cerevisiae Proteins metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1083-351X
- Volume :
- 291
- Issue :
- 52
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 27821593
- Full Text :
- https://doi.org/10.1074/jbc.M116.756098