Analysis of the interaction of TATA-box binding protein 1 and 2 from Taenia solium to TATA-box: structural factors related to selectivity and affinity.

TATA-box binding protein (TBP) is a core subunit of the transcription factor TFIID and plays a pivotal role in recognizing the TATA-box in protein-coding genes, facilitating the assembly of the transcription preinitiation complex. In Taenia solium, only one TBP isoform (TsTBP1) has been previously reported. Here, we identify and characterize a second isoform, TsTBP2, using a combination of molecular biology and bioinformatics approaches. TsTBP2 shares 42% primary sequence identity with TsTBP1 and exhibits distinct expression patterns between cysticerci and adult stages. To investigate the molecular determinants of DNA recognition, selectivity, and binding affinity, we performed molecular docking and molecular dynamics simulations for both TsTBPs with various TATA-box sequences. Our results reveal that TsTBP1 exhibits higher affinity for T. solium TATA-box sequences compared to the consensus AdML TATA-box (TATAAAAG), largely due to the specific interaction of critical phenylalanine residues with the DNA minor groove, which induces DNA bending and stabilizes the TBP-DNA complex. Furthermore, analysis of the Buckle parameter indicates that these Phe residues are the principal contributors to DNA distortion. To our knowledge, this study represents the first analysis of TBP selectivity and affinity in cestodes, providing insights into the molecular mechanisms underlying transcriptional regulation in T. solium.