High-resolution structure of the HNF-1alpha dimerization domain.
High-resolution structure of the HNF-1alpha dimerization domain.
复制标题
HNF-1α 二聚结构域的高分辨率结构。
作者：
Rose,RB;Endrizzi,JA;Cronk,JD;Holton,J;Alber,T
The N-terminal dimerization domain of the transcriptional activator hepatocyte nuclear factor-1α (HNF-1α) 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 Å resolution X-ray crystal structure of the dimerization domain of HNF-1α (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-1β rationalize the functional heterodimerization of the HNF-1α and HNF-1β proteins. Mutations in HNF-1α 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.
