RESUMO
Neutral endopeptidase (NEP) is the major enzyme involved in the metabolic inactivation of a number of bioactive peptides including the enkephalins, substance P, endothelin, bradykinin and atrial natriuretic factor, as well as the incretin hormone glucagon-like peptide 1 (GLP-1), which is a potent stimulator of insulin secretion. The activity of GLP-1 is also rapidly abolished by the serine protease dipeptidyl peptidase IV (DPP-IV), which led to an elevated interest in inhibitors of this enzyme for the treatment of type II diabetes. A dual NEP/DPP-IV inhibitor concept is proposed, offering an alternative strategy for the treatment of type 2 diabetes. Here, the synthesis and crystal structures of the soluble extracellular domain of human NEP (residues 52-749) complexed with the NEP, competitive and potent dual NEP/DPP-IV inhibitor MCB3937 are described.
Assuntos
Inibidores de Adenosina Desaminase , Inibidores da Dipeptidil Peptidase IV , Glicoproteínas/antagonistas & inibidores , Neprilisina/antagonistas & inibidores , Neprilisina/metabolismo , Oligopeptídeos/química , Oligopeptídeos/farmacologia , Adenosina Desaminase/metabolismo , Ligação Competitiva , Cristalografia por Raios X , Diabetes Mellitus Tipo 2/tratamento farmacológico , Dipeptidil Peptidase 4/metabolismo , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Glicoproteínas/metabolismo , Humanos , Modelos Moleculares , Estrutura Molecular , Neprilisina/química , Fragmentos de Peptídeos/química , Ligação Proteica , Estrutura Terciária de Proteína , Zinco/químicaRESUMO
High-resolution crystal structures of Staphylococcus aureus methionine aminopeptidase I in complex with various keto heterocycles and aminoketones were determined, and the intermolecular ligand interactions with the enzyme are reported. The compounds are effective inhibitors of the S. aureus enzyme because of the formation of an uncleavable tetrahedral intermediate upon binding. The electron densities unequivocally show the enzyme-catalyzed transition-state analogue mimicking that for amide bond hydrolysis of substrates.
Assuntos
Aminas/química , Aminopeptidases/antagonistas & inibidores , Aminopeptidases/química , Cetonas/química , Piridinas/química , Staphylococcus aureus/enzimologia , Tiazóis/química , Sítios de Ligação , Cristalografia por Raios X , Ciclopropanos/química , Metionil Aminopeptidases , Modelos Moleculares , Estrutura MolecularRESUMO
Methionyl aminopeptidases (MetAPs) represent a unique class of protease that are responsible for removing the N-terminal methionine residue from proteins and peptides. There are two major classes of MetAPs (type I and type II) described and each class can be subdivided into two subclasses. Eukaryotes contain both the type I and type II MetAPs, whereas prokaryotes possess only the type I enzyme. Due to the physiological importance of these enzymes there is considerable interest in inhibitors to be used as antiangiogenic and antimicrobial agents. Here, we describe the 1.15A crystal structure of the Staphylococcus aureus MetAP-I as an apo-enzyme and its complexes with various 1,2,4-triazole-based derivatives at high-resolution. The protein has a typical "pita-bread" fold as observed for the other MetAP structures. The inhibitors bind in the active site with the N1 and N2 atoms of the triazole moiety complexing two divalent ions. The 1,2,4-triazols represent a novel class of potent non-peptidic inhibitors for the MetAP-Is.
Assuntos
Aminopeptidases/química , Inibidores Enzimáticos/química , Staphylococcus aureus/enzimologia , Triazóis/química , Sequência de Aminoácidos , Aminopeptidases/genética , Aminopeptidases/metabolismo , Apoenzimas , Sítios de Ligação , Cristalografia por Raios X , Humanos , Substâncias Macromoleculares , Metionil Aminopeptidases , Modelos Moleculares , Dados de Sequência Molecular , Estrutura Molecular , Conformação Proteica , Dobramento de Proteína , Estrutura Terciária de Proteína , Alinhamento de SequênciaRESUMO
Dipeptidyl peptidase IV is a multifunctional type II transmembrane serine protease glycoprotein. The high-resolution crystal structure of the homodimeric human apo dipeptidyl peptidase IV has been determined at 1.9 A resolution. In addition, the structure of the binary complex with 1-[([2-[(5-iodopyridin-2-yl)amino]-ethyl]amino)-acetyl]-2-cyano-(S)-pyrrolidine has been solved, revealing the nature of the covalent interaction with the active-site serine.
