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Protein Sci. 2017 Nov;26(11):2280-2290. doi: 10.1002/pro.3287. Epub 2017 Sep 27.

Identification of heteromolecular binding sites in transcription factors Sp1 and TAF4 using high-resolution nuclear magnetic resonance spectroscopy.

Author information

1
Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Sakyo-ku, 606-8501, Japan.
2
Research Reactor Institute, Kyoto University, Sennan-gun, Osaka, 590-0494, Japan.
3
Faculty of Pharmaceutical Sciences, Doshisha Women's University, Kyotanabe city, Kyoto, 610-0395, Japan.

Abstract

The expression of eukaryotic genes is precisely controlled by interactions between general transcriptional factors and promoter-specific transcriptional activators. The fourth element of TATA-box binding protein-associated factor (TAF4), an essential subunit of the general transcription factor TFIID, serves as a coactivator for various promoter-specific transcriptional regulators. Interactions between TAF4 and site-specific transcriptional activators, such as Sp1, are important for regulating the expression levels of genes of interest. However, only limited information is available on the molecular mechanisms underlying the interactions between these transcriptional regulatory proteins. We herein analyzed the interaction between the transcriptional factors Sp1 and TAF4 using high-resolution solution nuclear magnetic resonance spectroscopy. We found that four glutamine-rich (Q-rich) regions in TAF4 were largely disordered under nearly physiological conditions. Among them, the first Q-rich region in TAF4 was essential for the interaction with another Q-rich region in the Sp1 molecule, most of which was largely disordered. The residues responsible for this interaction were specific and highly localized in a defined region within a range of 20-30 residues. Nevertheless, a detailed analysis of 13 C-chemical shift values suggested that no significant conformational change occurred upon binding. These results indicate a prominent and exceptional binding mode for intrinsically disordered proteins other than the well-accepted concept of "coupled folding and binding."

KEYWORDS:

coupled folding and binding; intrinsically disordered proteins; molecular interaction; nuclear magnetic resonance; transcriptional factor

PMID:
28857320
PMCID:
PMC5654864
DOI:
10.1002/pro.3287
[Indexed for MEDLINE]
Free PMC Article

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