Fig. 7
The ID3-TCF3-CFBA2T3 complex. a Protein structure of TCF3 (green) in complex with ID3 (blue) and bound to DNA (bottom). The N-terminal region that interacts with CBFA2T3 (orange) is separated by a long disordered/unstructured region (shown as a looped line). b Alignment of the DNA-binding region (residues 527–644) of TCF3 (Uniprot: P15923). The location of the domain is inferred by sequence similarity to the structure from protein databank code 2ypa chain A (a heterodimeric complex involving an equivalent domain from human TAL1 in complex with DNA). Differences between the sequences are highlighted (uncolored and bold for uncharged amino acids; red for negatively charged and blue for positively charged amino acids). Note that many changes alter the charge in one isoform relative to the other, leading to a net gain of four negative charges in isoform E12 relative to isoform E47. c Representations of the electrostatic surface of the E12 (left) and E47 (right) isoforms. The surface of E47 has a more positive electrostatic potential (blue). Also indicated is the loss of four negative (Glu/Asp) residues at the N-terminal portion of the domain, which were not present in the model (as there was no suitable structural template for them). The loss of these four negative charges also means that the E47 isoform is relatively more positively charged
