Primary Citation of Related Structures: 1G2Y, 1G2Z, 1G39
PubMed Abstract:
The N-terminal dimerization domain of the transcriptional activator hepatocyte nuclear factor-1alpha (HNF-1alpha) is essential for DNA binding and association of the transcriptional coactivator, DCoH (dimerization cofactor of HNF-1). To investigate the basis for dimerization of HNF-1 proteins, we determined the 1 ...
The N-terminal dimerization domain of the transcriptional activator hepatocyte nuclear factor-1alpha (HNF-1alpha) is essential for DNA binding and association of the transcriptional coactivator, DCoH (dimerization cofactor of HNF-1). To investigate the basis for dimerization of HNF-1 proteins, we determined the 1.2 A resolution X-ray crystal structure of the dimerization domain of HNF-1alpha (HNF-p1). Phasing was facilitated by devising a simple synthesis for Fmoc-selenomethionine and substituting leucine residues with selenomethionine. The HNF-1 dimerization domain forms a unique, four-helix bundle that is preserved with localized conformational shifts in the DCoH complex. In three different crystal forms, HNF-p1 displays subtle shifts in the conformation of the interhelix loop and the crossing angle between the amino- and carboxyl-terminal helices. In all three crystal forms, the HNF-p1 dimers pair through an exposed hydrophobic surface that also forms the binding site for DCoH. Conserved core residues in the dimerization domain of the homologous transcriptional regulator HNF-1beta rationalize the functional heterodimerization of the HNF-1alpha and HNF-1beta proteins. Mutations in HNF-1alpha are associated with maturity-onset diabetes of the young type 3 (MODY3), and the structure of HNF-p1 provides insights into the effects of three MODY3 mutations.
Related Citations:
Structural basis of dimerization, coactivator recognition and MODY3 mutations in HNF-1alpha Rose, R.B., Bayle, J.H., Endrizzi, J.A., Cronk, J.D., Crabtree, G.R., Alber, T. (2000) Nat Struct Biol 7: 744
Organizational Affiliation:
Department of Molecular and Cell Biology, 229 Stanley Hall #3206, University of California, Berkeley, California 94720-3206, USA.
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