To determine which domains of Tat and p53 interact, we analyzed the last 200 ns of model_ZDOCK's replica 1, which exhibits the highest binding energy. This analysis was performed using the PyContact tool. In this replica, we see that both N-domain and the basic of Tat bind to p53, as suggested by Gabizon. Some interactions are: (i) hydrogen bonds between Tyr32-Thr329, Tyr32-Gln331, Cys34-Thr329, (ii) salt-bridges between Arg49-Glu343, Arg52-Glu339, Lys50-Glu343 (See Table ). Additionally, it is noteworthy that the C-terminal domain of Tat contributes minimally to its binding with p53. Specifically, only one residue, Glu87, forms a salt bridge with Lys351. Collectively, our results indicate that the interaction between the two proteins primarily involves the basic patch (residues 47-57) and the N-terminal region of Tat (residues 1-40). This partially aligns with a previous observation suggesting that Tat (residues 73-86) may also be involved in complex formation with p53 . what dictates the binding energy was the number of hydrogen bonds between two proteins, in that more hydrogen bonds would translate into higher binding energy between proteins. However, hydrogen bond analyses revealed that the number of hydrogen bonds formed between proteins in each replica is consistently close, indicating that it cannot be the sole factor governing the binding energy (Figures ). For this reason, further detailed structural analysis is certainly needed to substantiate any conclusive finding. The last finding pertains to the binding conformation of p53. To this respect, Gabizon and colleagues elucidate that the negatively charged residues Glu343, Glu346, and Glu349 within the p53(326-355) region mediates the initial contact between the two proteins. This is unsurprising given the high charge content of the Tat(47-57) region. Model_ZDOCK's replica 1 also confirms hydrogen bonds and salt bridges between p53(Glu343) and Tat(Arg49) residues in the last 200 ns. However, Glu346 and Glu349 do not appear to play a role during the complexation between the two proteins according to our model.