## 3 Results and Discussion
### Influence of Dipole Orientation of ZW on the Interactions with Human Serum Proteins  
Molecular docking was performed first on the proposed ZWs before the zwitterionization of the PES membrane model to examine the impact of dipole orientation on ZW interactions, followed by the evaluating of ZW-PES interactions. MPC is a bio-inspired zwitterionic structure with extensive hydrophilicity, hemocompatibility, and antifouling qualities, which has strong potential applicability for drug delivery systems and biomedical devices [47; 48; 49]. The choline phosphates (like MBP and MMP) that result from reversing this zwitterionic structure (MPC) have a wide range of structural diversity and interactions [50]. Figure 3 represents the energy-minimized conformation of MMP and MPC. Docking results of the MMP and MPC with HSA, FB, and Tr were presented in Figures 4 and 5. PyMOL and Discovery Studio Visualizer illustrations showed significant differences between optimized structures with minimized energies for MMP and MPC (Figure 3). While MPC displayed a linear conformation at the lowest energy level, MMP presented a shrinkage conformation. This indicates that MMP chains have stronger electrostatic dipole-dipole interactions, which can lead to more self-assembly in this ZW chain. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Ligand** & **Protein** & \begin{tabular}{c} **Binding Energy** \\ **(kcal/mol)** \\ \end{tabular} & \multicolumn{2}{c}{**Receptor Contacts**} \\ \cline{3-5}  & PES & HSA & \(-10.3\) & \begin{tabular}{c} Arg209, Glu354 \({}^{*}\), Lys351 \({}^{*}\), \\ Ser480 \({}^{*}\), Lys212 \({}^{*}\), Asp324 \({}^{*}\), \\ \end{tabular} & \begin{tabular}{c} Leu347, Ala350, Val 482, Ala213, \\ Leu327, Val216, Phe228, Gly328, \\ Leu 331, Ala210, Val215, Leu481 \\ \end{tabular} \\ PES & FB & \(-8.5\) & \begin{tabular}{c} Ser47, Arg50, Lys29 \({}^{*}\), Cyst9 \({}^{*}\), \\ Cys76 \({}^{*}\), Lys58 \({}^{*}\), Asp30 \({}^{*}\), \\ \end{tabular} & \begin{tabular}{c} Li459, Ala27, Val74, Gly28, \\ Trp33, Leu72, Pro70, Leu66 \\ \end{tabular} \\ PES & Tr & \(-9.2\) & \
\begin{tabular}{c} *, Lys296 \({}^{*}\), His249 \({}^{*}\), Asp292 \({}^{*}\), Lys193 \({}^{*}\), Glu83 \({}^{*}\), Lys291 \({}^{*}\), \\ \end{tabular} &
\begin{tabular}{c} Phe295, Tyr818, Gly187, Thr181, \\ Gln184, Gly190, Ala191 \\ \end{tabular} \\ \hline \hline \end{tabular}  
*: Weak Van der Waals interactions.  
\end{table} 
Table 1: Binding energy and receptor contacts of HSA, FB, and Tr interactions with PES. Figure 3: Minimized-energy structure of MMP and MPC zwitterions with (**a**) PyMOL and (**b**) Discovery Studio Visualizer. Furthermore, it leads to the formation of a stronger hydration shell with H\({}_{2}\)O molecules, which improves antifouling and hemocompatibility properties. Docking studies showed that MPC had higher affinity energies for all the ligand-protein interactions compared to MMP. As presented in Table 2, MPC binds to the active sites of HSA, FB, and Tr, with affinities of \(-6\), \(-5.9\), and \(-5.7\) kcal/mol, respectively, whereas MMP binds with lower affinities of \(-5.5\), \(-4.9\), \(-4.6\) kcal/mol. As a purely helical protein, with 67% helices in its secondary structure and 585 amino acids in its primary sequence, the ZW ligands (MMP and MPC) bind to the polar sites of HSA with a higher affinity binding interaction than FB and Tr. The amino acids Leu347, Gly328, Ala350, Leu327, Gly354, Leu331, Ala210, and Ala213 were engaged in hydrophobic interaction between MMP and HSA, as presented in Figure 5. Furthermore, the Leu481, Val482, Ser480, Asp324, Arg209, and Lys35 interacted in a hydrophilic manner with MMP. On the other hand, MPC had polar interactions with HAS via Glu153, Glu292, Lys199, Arg222, Arg257, His 242, Ser192, and Lys195, which occured from different polar positions. Thr181, Phe192, Ser189, Asn213, Gln184, Gly290, and Leu293 are further examples of MPC-HSA hydrophobic interactions.