3U5V

Crystal structure of Max-E47

Summary for 3U5V

• Entry DOI: 10.2210/pdb3u5v/pdb
• Descriptor: Protein max, Transcription factor E2-alpha chimera, NITRATE ION (3 entities in total)
• Functional Keywords: basic helix-loop-helix (bhlh), transcription factor, transcription
• Biological source: Mus musculus (mouse, human); More
• Cellular location: Nucleus: P15923
• Total number of polymer chains: 1
• Total formula weight: 9199.50

Authors

Guarne, A.,Ahmadpour, F.,Gloyd, M. (deposition date: 2011-10-11, release date: 2012-03-21, Last modification date: 2023-09-13)

Primary citation

Ahmadpour, F.,Ghirlando, R.,De Jong, A.T.,Gloyd, M.,Shin, J.A.,Guarne, A.
Crystal structure of the minimalist max-e47 protein chimera.
Plos One, 7:e32136-e32136, 2012

PubMed Abstract: Max-E47 is a protein chimera generated from the fusion of the DNA-binding basic region of Max and the dimerization region of E47, both members of the basic region/helix-loop-helix (bHLH) superfamily of transcription factors. Like native Max, Max-E47 binds with high affinity and specificity to the E-box site, 5'-CACGTG, both in vivo and in vitro. We have determined the crystal structure of Max-E47 at 1.7 Å resolution, and found that it associates to form a well-structured dimer even in the absence of its cognate DNA. Analytical ultracentrifugation confirms that Max-E47 is dimeric even at low micromolar concentrations, indicating that the Max-E47 dimer is stable in the absence of DNA. Circular dichroism analysis demonstrates that both non-specific DNA and the E-box site induce similar levels of helical secondary structure in Max-E47. These results suggest that Max-E47 may bind to the E-box following the two-step mechanism proposed for other bHLH proteins. In this mechanism, a rapid step where protein binds to DNA without sequence specificity is followed by a slow step where specific protein:DNA interactions are fine-tuned, leading to sequence-specific recognition. Collectively, these results show that the designed Max-E47 protein chimera behaves both structurally and functionally like its native counterparts.

PubMed: 22389683
DOI: 10.1371/journal.pone.0032136

Experimental method

X-RAY DIFFRACTION (1.7 Å)