Human TCF4 C-terminal bHLH domain in Complex with 13-bp Oligonucleotide Containing E-box SequenceHuman TCF4 C-terminal bHLH domain in Complex with 13-bp Oligonucleotide Containing E-box Sequence

Structural highlights

6od3 is a 12 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 1.494Å
Ligands:, ,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Disease

ITF2_HUMAN Autosomal dominant non-syndromic intellectual disability;Fuchs endothelial corneal dystrophy;Pitt-Hopkins syndrome;Schizophrenia;Primary sclerosing cholangitis. The disease is caused by mutations affecting the gene represented in this entry.

Function

ITF2_HUMAN Transcription factor that binds to the immunoglobulin enchancer Mu-E5/KE5-motif. Involved in the initiation of neuronal differentiation. Activates transcription by binding to the E box (5'-CANNTG-3'). Binds to the E-box present in the somatostatin receptor 2 initiator element (SSTR2-INR) to activate transcription (By similarity). Preferentially binds to either 5'-ACANNTGT-3' or 5'-CCANNTGG-3'.

Publication Abstract from PubMed

The psychiatric risk-associated transcription factor 4 (TCF4) is linked to schizophrenia. Rare TCF4 coding variants are found in individuals with Pitt-Hopkins syndrome-an intellectual disability and autism spectrum disorder. TCF4 contains a C-terminal basic-helix-loop-helix (bHLH) DNA binding domain which recognizes the enhancer-box (E-box) element 5'-CANNTG-3' (where N = any nucleotide). A subset of the TCF4-occupancy sites have the expanded consensus binding specificity 5'-C(A/G)-CANNTG-3', with an added outer Cp(A/G) dinucleotide; for example in the promoter for CNIH3, a gene involved in opioid dependence. In mammalian genomes, particularly brain, the CpG and CpA dinucleotides can be methylated at the 5-position of cytosine (5mC), and then may undergo successive oxidations to the 5-hydroxymethyl (5hmC), 5-formyl (5fC), and 5-carboxyl (5caC) forms. We find that, in the context of 5'-0CG-1CA-2CG-3TG-3'(where the numbers indicate successive dinucleotides), modification of the central E-box 2CG has very little effect on TCF4 binding, E-box 1CA modification has a negative influence on binding, while modification of the flanking 0CG, particularly carboxylation, has a strong positive impact on TCF4 binding to DNA. Crystallization of TCF4 in complex with unmodified or 5caC-modified oligonucleotides revealed that the basic region of bHLH domain adopts multiple conformations, including an extended loop going through the DNA minor groove, or the N-terminal portion of a long helix binding in the DNA major groove. The different protein conformations enable arginine 576 (R576) to interact, respectively, with a thymine in the minor groove, a phosphate group of DNA backbone, or 5caC in the major groove. The Pitt-Hopkins syndrome mutations affect five arginine residues in the basic region, two of them (R569 and R576) involved in 5caC recognition. Our analyses indicate, and suggest a structural basis for, the preferential recognition of 5caC by a transcription factor centrally important in brain development.

Structural basis for preferential binding of human TCF4 to DNA containing 5-carboxylcytosine.,Yang J, Horton JR, Li J, Huang Y, Zhang X, Blumenthal RM, Cheng X Nucleic Acids Res. 2019 May 13. pii: 5488531. doi: 10.1093/nar/gkz381. PMID:31081034[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

  1. Yang J, Horton JR, Li J, Huang Y, Zhang X, Blumenthal RM, Cheng X. Structural basis for preferential binding of human TCF4 to DNA containing 5-carboxylcytosine. Nucleic Acids Res. 2019 May 13. pii: 5488531. doi: 10.1093/nar/gkz381. PMID:31081034 doi:http://dx.doi.org/10.1093/nar/gkz381

6od3, resolution 1.49Å

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