Banca de DEFESA: THAMILLA MARIA SILVA MACIEL

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : THAMILLA MARIA SILVA MACIEL
DATE: 27/02/2023
TIME: 14:00
LOCAL: Google Meet
TITLE:

MAPPING OF INTERACTIONS BETWEEN BIOLOGICALLY ACTIVE COMPOUNDS WITH UREASE: DEVELOPMENT OF UREASE INHIBITORS WITH POTENTIAL CLINICAL AND AGRICULTURAL APPLICATION.

KEY WORDS:

urease; inhibitors; amino acid derivatives; thiourea derivatives; julolidine derivatives; biophysical studies; spectroscopic techniques

PAGES: 162
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUMMARY:

The inhibition of urease activity can be explored in several areas, and mainly in the clinical and agricultural context. Thus, efforts have been made to develop effective inhibitors for this purpose. Thus, this work proposes to evaluate the activity of julolidine and amino acid derivatives (with thiourea nucleus) as in vitro urease inhibitors. Enzyme inhibition studies indicated that the RS12-J2 derivative of the julolidine class acted as a competitive inhibitor, while the other derivatives as mixed inhibitors. By molecular fluorescence, it was verified that the Kb values (binding constant) obtained indicate an intermediate to strong binding force, with the RS12 derivatives (J1 and J2) showing the highest Kb values (0.10 - 7.33× 106 M-1). The quenching mechanism of this process was preferably static. Hydrophobic interactions were the predominant forces in the stabilization of the enzyme-ligand complex for the RS11 derivatives (ΔH > 0 and ΔS > 0), and van der Waals forces and hydrogen bonds (ΔH < 0 and ΔS < 0) for the RS12 derivatives. Using the RS12-J2 derivative as a model, it was verified in the 3D fluorescence, UV-vis and synchronized fluorescence studies that the interaction process led to alteration in the native structure of the enzyme and the microregion close to the Tyr residue (active site) was more affected, corroborating with the study of interaction with Ni(II) cations by molecular absorption spectroscopy (complex formation). Through competition studies, it was proved that the RS12-J2 derivative acts in the active site of the enzyme. The study of resonant energy transfer (FRET) indicated that there was non-radiative energy transfer. The evaluation of the inhibitory potential of the RS12-J1 and RS12-J2 compounds on soil ureases showed that the RS12-J2 derivative showed equivalent efficiency to the NBPT (commercial inhibitor) for soils S1 and S4, which have a high content of organic matter. Finally, in studies using molecular docking, it was observed that the orientation of the dihydrofuran ring plays an essential role in the coordination involving the free electron pair of the oxygen atom of the dihydrofuran ring and the Ni(II) ions. For the amino acid derivatives, the values of the inhibitory concentration (IC50) were initially determined to evaluate the potential of these compounds to inhibit the activity of Jack bean urease (model), obtaining values between 0.37 - 0.74 µM, however, the influence of enantioselectivity was not verified, and of the organic matter since the values did not differ statistically at a confidence level of 95%, this trend was also obtained in the interaction studies for the Kb values. Thermodynamic parameters indicated a spontaneous process. The possible intermolecular interactions involved in the process of interaction between urease and the derivatives 110-L, 110-D, 110 ac-L, 110 ac-D and 116 were van der Waals forces and hydrogen bonds, for the derivatives 106 ac -L and 106 ac-D were the hydrophobic interactions. Furthermore, the occurrence of static quenching was observed, and that there was no influence of ionic strength on the interaction process at a confidence level of 95%, with the exception of compound 110-L. The 3D fluorescence and UV-vis studies indicated changes in the secondary structure after the interaction process, in which there was non-radiative energy transfer. The study by synchronized fluorescence indicated that derivatives 110 ac-L, 110 ac-D and 116 bind to the microregion close to the Tyr residue. Derivatives 110-L and 110-D interact close to Trp residues. The competition study indicated that amino acid derivatives competed for the active site, in the presence of classical inhibitors, corroborating the study of interaction with Ni(II) cations by molecular absorption spectroscopy. In tests using soil samples, it was observed that for all soils, derivatives were more potent when compared to NBPT. Thus, derivatives of julolidines and derivatives of amino acids showed inhibition of urease activity in vitro, and in soil samples, being possible potent urease inhibitors.

BANKING MEMBERS:
Externo(a) à Instituição - CLEITON MOREIRA DA SILVA - UFMG
Externo(a) à Instituição - FRANCISCO ANTÔNIO DA SILVA CUNHA - UFAL
Interno(a) - 1811274 - HUGO JUAREZ VIEIRA PEREIRA
Interno(a) - 1006306 - JADRIANE DE ALMEIDA XAVIER
Presidente - 1613338 - JOSUE CARINHANHA CALDAS SANTOS