6V8U

Kaiso (ZBTB33) zinc finger DNA binding domain in complex with a modified Kaiso binding sequence (KBS)

6V8U の概要

• エントリーDOI: 10.2210/pdb6v8u/pdb
• 関連するPDBエントリー: 6DF5 6DF8 6DF9 6DFA 6DFB 6DFC
• 分子名称: Transcriptional regulator Kaiso, DNA (5'-D(*TP*GP*CP*TP*TP*CP*GP*TP*GP*CP*CP*AP*AP*TP*AP*AP*CP*G)-3'), DNA (5'-D(*CP*GP*TP*TP*AP*TP*TP*GP*GP*CP*AP*CP*GP*AP*AP*GP*CP*A)-3'), ... (7 entities in total)
• 機能のキーワード: dna methylation, zinc finger, transcriptional regulator, dna binding protein
• 由来する生物種: Homo sapiens (Human); 詳細
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 27504.61

構造登録者

Nikolova, E.N.,Stanfield, R.L.,Dyson, H.J.,Wright, P.E. (登録日: 2019-12-12, 公開日: 2020-04-15, 最終更新日: 2023-10-11)

主引用文献

Nikolova, E.N.,Stanfield, R.L.,Dyson, H.J.,Wright, P.E.
A Conformational Switch in the Zinc Finger Protein Kaiso Mediates Differential Readout of Specific and Methylated DNA Sequences.
Biochemistry, 59:1909-1926, 2020

PubMed Abstract: Recognition of the epigenetic mark 5-methylcytosine (mC) at CpG sites in DNA has emerged as a novel function of many eukaryotic transcription factors (TFs). It remains unclear why the sequence specificity of these TFs differs for CpG-methylated motifs and consensus motifs. Here, we dissect the structural and dynamic basis for this differential DNA binding specificity in the human zinc finger TF Kaiso, which exhibits high affinity for two consecutive mCpG sites in variable contexts and also for a longer, sequence-specific Kaiso binding site (KBS). By integrating structural analysis and DNA binding studies with targeted protein mutagenesis and nucleotide substitutions, we identify distinct mechanisms for readout of methylated and KBS motifs by Kaiso. We show that a key glutamate residue (E535), critical for mCpG site recognition, adopts different conformations in complexes with specific and methylated DNA. These conformational differences, together with intrinsic variations in DNA flexibility and/or solvation at TpG versus mCpG sites, contribute to the different DNA affinity and sequence specificity. With methylated DNA, multiple direct contacts between E535 and the 5' mCpG site dominate the binding affinity, allowing for tolerance of different flanking DNA sequences. With KBS, Kaiso employs E535 as part of an indirect screen of the 5' flanking sequence, relying on key tyrosine-DNA interactions to stabilize an optimal DNA conformation and select against noncognate sites. These findings demonstrate how TFs use conformational adaptation and exploit variations in DNA flexibility to achieve distinct DNA readout outcomes and target a greater variety of regulatory and epigenetic sites than previously appreciated.

PubMed: 32352758
DOI: 10.1021/acs.biochem.0c00253

実験手法

X-RAY DIFFRACTION (2.103 Å)