Estudo de modelagem molecular e de inibição enzimática das calicreínas teciduais humanas 5 e 7 por compostos isocumarínicos e derivados de isomanídeos

• Ano de defesa: 2011
• Autor(a) principal: TEIXEIRA, Thiago Salem Pançonato
• Orientador(a): ABRAHÃO JUNIOR, Odonírio
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Triângulo Mineiro
• Programa de Pós-Graduação: Curso de Pós-Graduação em Ciências Fisiológicas
• Departamento: Bioquímica, Fisiologia e Farmacologia
• País: BR
• Palavras-chave em Português: Calicreína; Isomanídeo; Isocumarina; Docking Molecular
• Palavras-chave em Inglês: Kallikreins; Isomannide; Isocoumarins; Molecular Docking
• Área do conhecimento CNPq: CNPQ::CIENCIAS DA SAUDE::NUTRICAO::BIOQUIMICA DA NUTRICAO
• Link de acesso: http://localhost:8080/tede/handle/tede/61

The human tissue kallikrein family is composed of fifteen serine proteases, being the nomenclature for gene and protein denoted KLK and KLK , respectively, followed by its corresponding number. Twelve are expected to have trypsin-like activity and three, KLK3, 7 and 9, to have chymotrypsin-like activity. All of them are expressed as pre-pro-enzyme, which after reaching its main location the pre-peptide fragment is removed. The pro-peptide keeps its latency and, once it is removed, other factors control their activity as allosteric inhibition, internal cleavage and/or endogenous inhibition. They are expressed in almost every tissue, being involved in many functions as vascular tonus regulation, semen liquefaction, extracellular matrix remodeling, neuronal remodeling, pro-hormones activation, and so on. Many studies are being made over the action of these enzymes on cancer development, which depends on the tissue and factors involved in the medium, they can difficult or facilitate the development through its involvement on metastases and angiogenesis. Among those enzymes, we focused on KLK5 and KLK7, which have expression on the same tissues, with synergic action. Their most well described function is on the skin desquamation through proteolysis of the adhesion proteins. When their natural inhibitor is lacking, the patient has an intense skin detachment process (ictiosys), causing infection and inflammation. They can act in the extracellular matrix degradation, activating antimicrobial peptides and pro-inflammatory receptors. Because of the lacking of drugs that act over KLK5 and KLK7, we studied the behavior of a class of peptide mimetic compounds derived from isomannide, and isocoumarine compounds. From the fifteen peptide mimetic compounds, five were soluble on aqueous medium and were tested against KLK5, being three reversible and competitive inhibitors on micromolar range and two reversible and noncompetitive inhibitors, but with low potency. The three isocoumarine compounds were tested with both enzymes, and were reversible and competitive on the micromolar range, being the dimer form more potent. The molecular modeling study shows that the hydrophobic interaction and hydrogen bonds are the main force involved in the enzyme-inhibitor interaction. The three competitive peptide mimetic compounds have a similar binding mode, with its substituent R2 at S1 pocket, the R1 substituent at S2 pocket, and the isomannide ring and the O-benzyl group over S1 /S2 . These compounds made four hydrogen bonds, being two with the residues of the oxyanion hole. The isocumarine compounds, for both enzymes, fits on S1 pocket, and for KLK5 the dimer form goes over S3/S4 pocket and for KLK7 over S1 . For the KLK5, they make hydrogen bonds with the residues of the oxyanion hole, but the same do not happens with KLK7, which indicates why they are more potent for KLK5 than for KLK7, even though KLK7 having a more hydrophobic surface and a larger S1 pocket. We believe that hydrophobic compounds with lateral chain similar to basic amino acid and similar to hydrophobic amino acid may give better inhibition for KLK5 and KLK7, respectively.