2c6y
Crystal structure of interleukin enhancer-binding factor 1 bound to DNA
Structural highlights
FunctionFOXK2_HUMAN Recognizes the core sequence 5'-TAAACA-3'. Binds to NFAT-like motifs (purine-rich) in the IL2 promoter. Also binds to HIV-1 long terminal repeat. May be involved in both positive and negative regulation of important viral and cellular promoter elements.[1] [2] 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 PubMedInterleukin enhancer binding factor (ILF) is a human transcription factor and a new member of the winged helix/forkhead family. ILF can bind to purine-rich regulatory motifs such as the human T-cell leukemia virus-long terminal region and the interleukin-2 promoter. Here we report the 2.4 A crystal structure of two DNA binding domains of ILF (FOXK1a) binding to a 16-bp DNA duplex containing a promoter sequence. Electrophoretic mobility shift assay studies demonstrate that two ILF-DNA binding domain molecules cooperatively bind to DNA. In addition to the recognition helix recognizing the core sequences through the major groove, the structure shows that wing 1 interacts with the minor groove of DNA, and the H2-H3 loop region makes ionic bonds to the phosphate group, which permits the recognition of DNA. The structure also reveals that the presence of the C-terminal alpha-helix in place of a typical wing 2 in a member of this family alters the orientation of the C-terminal basic residues (RKRRPR) when binding to DNA outside the core sequence. These results provide a new insight into how the DNA binding specificities of winged helix/forkhead proteins may be regulated by their less conserved regions. Crystal structure of the human FOXK1a-DNA complex and its implications on the diverse binding specificity of winged helix/forkhead proteins.,Tsai KL, Huang CY, Chang CH, Sun YJ, Chuang WJ, Hsiao CD J Biol Chem. 2006 Jun 23;281(25):17400-9. Epub 2006 Apr 18. PMID:16624804[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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