Structure of a HoxB1-Pbx1 heterodimer bound to DNA: Role of the hexapeptide and a fourth homeodomain helix in complex formation

Derek E. Piper, Adrian H. Batchelor, Ching Pin Chang, Michael L. Cleary, Cynthia Wolberger

Research output: Contribution to journalArticle

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Hox homeodomain proteins are developmental regulators that determine body plan in a variety of organisms. A majority of the vertebrate Hox proteins bind DNA as heterodimers with the Pbx1 homeodomain protein. We report here the 2.35 Å structure of a ternary complex containing a human HoxB1-Pbx1 heterodimer bound to DNA. Heterodimer contacts are mediated by the hexapeptide of HoxB1, which binds in a pocket in fie Pbx1 protein formed in part by a three-amino acid insertion in the Pbx1 homeodomain. The Pbx1 DNA- binding domain is larger than the canonical homeodomain, containing an additional α helix that appears to contribute to binding of the HoxB1 hexapeptide and to stable binding of Pbx1 to DNA. The structure suggests a model for modulation of Hox DNA binding activity by Pbx1 and related proteins.

Original languageEnglish (US)
Pages (from-to)587-597
Number of pages11
Issue number4
StatePublished - Feb 19 1999


ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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