1B8I

STRUCTURE OF THE HOMEOTIC UBX/EXD/DNA TERNARY COMPLEX

Summary for 1B8I

• Entry DOI: 10.2210/pdb1b8i/pdb
• Descriptor: DNA (5'-D(*GP*TP*CP*GP*CP*CP*AP*TP*AP*AP*AP*TP*CP*AP*C)-3'), DNA (5'-D(*AP*CP*GP*TP*GP*AP*TP*TP*TP*AP*TP*GP*GP*CP*G)-3'), PROTEIN (ULTRABITHORAX HOMEOTIC PROTEIN IV), ... (5 entities in total)
• Functional Keywords: dna binding, homeodomain, homeotic proteins, development, specificity, transcription-dna complex, transcription/dna
• Biological source: Drosophila melanogaster (fruit fly); More
• Cellular location: Nucleus: P83949 P40427
• Total number of polymer chains: 4
• Total formula weight: 26730.09

Authors

Passner, J.M.,Ryoo, H.-D.,Shen, L.,Mann, R.S.,Aggarwal, A.K. (deposition date: 1999-02-01, release date: 1999-04-12, Last modification date: 2023-12-27)

Primary citation

Passner, J.M.,Ryoo, H.D.,Shen, L.,Mann, R.S.,Aggarwal, A.K.
Structure of a DNA-bound Ultrabithorax-Extradenticle homeodomain complex.
Nature, 397:714-719, 1999

PubMed Abstract: During the development of multicellular organisms, gene expression must be tightly regulated, both spatially and temporally. One set of transcription factors that are important in animal development is encoded by the homeotic (Hox) genes, which govern the choice between alternative developmental pathways along the anterior-posterior axis. Hox proteins, such as Drosophila Ultrabithorax, have low DNA-binding specificity by themselves but gain affinity and specificity when they bind together with the homeoprotein Extradenticle (or Pbxl in mammals). To understand the structural basis of Hox-Extradenticle pairing, we determine here the crystal structure of an Ultrabithorax-Extradenticle-DNA complex at 2.4 A resolution, using the minimal polypeptides that form a cooperative heterodimer. The Ultrabithorax and Extradenticle homeodomains bind opposite faces of the DNA, with their DNA-recognition helices almost touching each other. However, most of the cooperative interactions arise from the YPWM amino-acid motif of Ultrabithorax-located amino-terminally to its homeodomain-which forms a reverse turn and inserts into a hydrophobic pocket on the Extradenticle homeodomain surface. Together, these protein-DNA and protein-protein interactions define the general principles by which homeotic proteins interact with Extradenticle (or Pbx1) to affect development along the anterior-posterior axis of animals.

PubMed: 10067897
DOI: 10.1038/17833

Experimental method

X-RAY DIFFRACTION (2.4 Å)