## 3 Results and Discussion
### Molecular Docking Investigation
They employed the molecular docking approach to check the interactions between Food and Drug Administration (FDA)-approved phytochemical compounds and the dispersin domain, corroborating their in silico observations with the in vitro antimicrobial activity against enteroaggregative _E. coli_. In agreement with the study of [PERSON] et al. [59], the interface of the thermodynamically stable complexes with QUE and RUT involved contacts with Ala [7], Trp [93], Ser [96] and Ser [98], including hydrogen bonds stabilizing the complexes (Table 6). The active sites involving these amino acids were reported by [PERSON] et al. [59] in the case of a complex with cinnamaldehyde, which yielded MIC values of \(0.25\)-\(0.50\)\(\mu\)L/mL and MBCs of \(0.50\)-\(1.00\)\(\mu\)L/mL against three different strains of enteroaggregative _E. coli_. Regarding _S. aureus_, the proteins used as receptors in the molecular docking procedure were tyrosyl-tRNA synthetase (TyrRS) (Figure 3c) and DNA gyrase (Figure 3d). TyrRS is an aminoacyl-tRNA synthetase that catalyzes the covalent attachment of amino acids to tRNA, an important step in the translation process [52]. Since TyrRS is essential for protein synthesis and therefore for bacterial cell life and integrity, identifying potent inhibitors targeting the activity of this enzyme from the virulent strains of _S. aureus_ is of particular importance. TyrRS is classified within the class I synthetases, having a specific Rossmann fold in the catalytic domain and the HIGH and KMSKS motifs involved in ATP binding [27]. Analyzing the results presented in Table 6, one can observe that all investigated ligands exhibited comparable affinity towards the TyrRS molecules, having \(\Delta\)G\({}_{\rm int}\) values in the \(-7.95\div-8.82\) kcal/mol range. Nonetheless, out of the TyrRS-based docking models, only the complex with QUE was thermodynamically stable (\(\Delta\)G\({}_{\rm diss}\) of \(8.1\) kcal/mol). In addition, the TyrRS-QUE model was characterized by the widest interaction surface of \(135.7\) A\({}^{2}\), involving hydrophobic contacts and five hydrogen bonds for the complex interface's stabilization (Table 6). Partial overlap of the active sites accommodating the four investigated phytochemicals on the surface of the enzyme was observed. All ligands were in direct contact with amino acids belonging to the N-terminal \(\alpha/\beta\) domain (0-220). The only exception concerned RUT, which was interfaced with Pro\({}^{222}\)-Val\({}^{224}\) and Phe\({}^{232}\)-Lys\({}^{243}\), belonging to the peptide that forms the connection with the \(\alpha\)-helical domain (248-232) [27]. Of particular importance is that all active sites share amino acids with the pockets described by [PERSON] et al. [27] for the accommodation of potent inhibitors of TyrRS. For instance, the binding sites of CAT, CLA and QUE share three or four amino acids, namely Ala [39], Asp [40], Thr [42] and His [50] (Table 6), with the binding pocket of SB-243545, which is a very strong TyrRS inhibitor [27]. On the other hand, CLA and RUT are in direct contact with Gly [38], His [50], Pro\({}^{53}\), Gly [193], Asp [195] and Gln [196] residues, also involved in the attachment of the SB-219383 inhibitor to TyrRS molecules [27]. Since all investigated ligands have an affinity towards the area comprising the HIGH motif (His\({}^{47}\)-His\({}^{50}\)), one might assume that phytochemical attachment will lead to changes in the active site of ATP [27], therefore interfering with the typical activity of the enzyme. In particular, RUT directly interfaces with the His\({}^{47}\), Gly [49] and His\({}^{50}\) residues of the HIGH motif, establishing one hydrogen bond with Gly [49]. Moreover, the RUT binding pocket also includes the Phe\({}^{232}\)Gly [233] and Lys [234] residues, which are part of the KFGKS motif.