Characterization of the interaction interface and conformational dynamics of human TGIF1 homeodomain upon the binding of consensus DNA

Publication date: Available online 23 July 2018Source: Biochimica et Biophysica Acta (BBA) - Proteins and ProteomicsAuthor(s): Shuangli Li, Rui Hu, Haijie Yao, Dong Long, Fan Luo, Xin Zhou, Xu Zhang, Maili Liu, Jiang Zhu, Yunhuang YangAbstractThe TG interacting factor-1 homeodomain (TGIF1-HD) binds with the consensus DNA motif 5’-TGTCA-3′ in gene promoters through its three-amino acid loop extension (TALE) type homeodomain, and then recruits co-regulators to regulate gene expression. Although the solution NMR structure of human TGIF1-HD has been reported previously, little is known about its DNA binding mechanism. NMR titrations have been extensively used to study mechanisms of ligand binding to target proteins; however, an intermediate exchange occurred predominantly between TGIF1-HD in the free and bound states when titrated with the consensus DNA, which resulted in poor-quality NMR spectra and precluded further exploration of its interaction interface and conformational dynamics. Here, the helix α3 of TGIF1-HD was speculated as the specific DNA binding interface by hydrogen–deuterium exchange mass spectrometry (HDX-MS) experiments, and subsequently confirmed by chemical exchange saturation transfer (CEST) spectroscopy. In addition, simultaneous conformational changes in other regions, including α1 and α2, were induced by DNA binding, explaining the observation of chemical shift perturbations from extensive residues besides those located in α3. Further, low-popula...
Source: Biochimica et Biophysica Acta (BBA) Proteins and Proteomics - Category: Biochemistry Source Type: research