7AW7

CCAAT-binding complex and HapX bound to Aspergillus nidulans cccA DNA

Summary for 7AW7

• Entry DOI: 10.2210/pdb7aw7/pdb
• Related: 6Y36 6Y37 7AW9
• Descriptor: HapB, Transcription factor HapC (Eurofung), CBFD_NFYB_HMF domain-containing protein, ... (8 entities in total)
• Functional Keywords: transcription factor, histone fold, basic leucine zipper, heteropentamer, protein-dna complex, transcription
• Biological source: Aspergillus nidulans FGSC A4; More
• Total number of polymer chains: 7
• Total formula weight: 77792.94

Authors

Huber, E.M.,Groll, M. (deposition date: 2020-11-06, release date: 2022-04-13, Last modification date: 2024-01-31)

Primary citation

Huber, E.M.,Hortschansky, P.,Scheven, M.T.,Misslinger, M.,Haas, H.,Brakhage, A.A.,Groll, M.
Structural insights into cooperative DNA recognition by the CCAAT-binding complex and its bZIP transcription factor HapX.
Structure, 30:934-, 2022

PubMed Abstract: The heterotrimeric CCAAT-binding complex (CBC) is a fundamental eukaryotic transcription factor recognizing the CCAAT box. In certain fungi, like Aspergilli, the CBC cooperates with the basic leucine zipper HapX to control iron metabolism. HapX functionally depends on the CBC, and the stable interaction of both requires DNA. To study this cooperative effect, X-ray structures of the CBC-HapX-DNA complex were determined. Downstream of the CCAAT box, occupied by the CBC, a HapX dimer binds to the major groove. The leash-like N terminus of the distal HapX subunit contacts the CBC, and via a flexible polyproline type II helix mediates minor groove interactions that stimulate sequence promiscuity. In vitro and in vivo mutagenesis suggest that the structural and functional plasticity of HapX results from local asymmetry and its ability to target major and minor grooves simultaneously. The latter feature may also apply to related transcription factors such as yeast Hap4 and distinct Yap family members.

PubMed: 35472306
DOI: 10.1016/j.str.2022.04.001

Experimental method

X-RAY DIFFRACTION (3.4 Å)