1du6
From Proteopedia
SOLUTION STRUCTURE OF THE TRUNCATED PBX HOMEODOMAIN
Structural highlights
Function[PBX1_MOUSE] Plays a role in the cAMP-dependent regulation of CYP17 gene expression via its cAMP-regulatory sequence (CRS1) 5'-ATCAATCAA-3'. Acts as a transcriptional activator of PF4 in complex with MEIS1. May have a role in steroidogenesis and, subsequently, sexual development and differentiation. Isoform PBX1b as part of a PDX1:PBX1b:MEIS2b complex in pancreatic acinar cells is involved in the transcriptional activation of the ELA1 enhancer; the complex binds to the enhancer B element and cooperates with the transcription factor 1 complex (PTF1) bound to the enhancer A element. Probably in complex with MEIS2, is involved in transcriptional regulation by KLF4. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedPBX 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 alpha-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. Conformational changes in the PBX homeodomain and C-terminal extension upon binding DNA and HOX-derived YPWM peptides.,Sprules T, Green N, Featherstone M, Gehring K Biochemistry. 2000 Aug 15;39(32):9943-50. PMID:10933814[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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