July 1, 2000
Journal Article

Conformational changes in the PBX homeodomain and C-terminal extension
upon binding DNA and HOX-derived YPWM peptides

Abstract

ABSTRACT: PBX is a member of the three amino acid loop extension (TALE) class of homeodomains. PBX binds DNA cooperatively with HOX homeodomain proteins that contain a conserved YPWM motif. The amino acids immediately C-terminal to the PBX homeodomain increase the affinity of the homeodomain for its DNA site and HOX proteins. We have determined the structure of the free PBX homeodomain using NMR spectroscopy. Both the PBX homeodomain and the extended PBX homeodomain make identical contacts with a 5?-TGAT-3? DNA site and a YPWM peptide. A fourth R-helix, which forms upon binding to DNA, stabilizes the extended PBX structure. Variations in DNA sequence selectivity of heterodimeric PBX-HOX complexes depend on the HOX partner; however, a comparison of five different HOX-derived YPWM peptides showed that each bound to PBX in the same way, differing only in the strength of the association.

Revised: July 28, 2003 | Published: July 1, 2000

Citation

Sprules T., N. Green, M. Featherstone, and K. Gehring. 2000. "Conformational changes in the PBX homeodomain and C-terminal extension upon binding DNA and HOX-derived YPWM peptides." Biochemistry 39, no. 32:9943-9950.