RESUMEN
The tetrameric folding of ß-tryptase and the pair-wise distribution of its substrate binding sites offer a unique opportunity for development of inhibitors that span two adjacent binding sites. A series of dimeric inhibitors with two basic P1 moieties was discovered using this design strategy and exhibited tight-binder characteristics. Using the same strategy, an attempt was made to design and synthesize dimeric inhibitors with two neutral-P1 groups in hope to exploit the dimeric binding mode to achieve a starting point for further optimization. The unsuccessful attempt, however, demonstrated the important role played by Ala190 in neutral-P1 binding and casted further doubt on the possibility of developing neutral-P1 inhibitors for ß-tryptase.
Asunto(s)
Multimerización de Proteína/efectos de los fármacos , Inhibidores de Serina Proteinasa/química , Inhibidores de Serina Proteinasa/farmacología , Triptasas/antagonistas & inhibidores , Sitios de UniónRESUMEN
A series of compounds with an amidinothiophene P1 group and a pyrrolidinone-sulphonamide scaffold linker was identified as potent inhibitors of human kallikrein 6 by structure-based virtual screening based on the union accessible binding space of serine proteases. As the first series of potent nonmechanism-based hK6 inhibitors, they may be used as tool compounds for target validation. An X-ray structure of a representative compound complexed with hK6, resolved at a resolution of 1.88 Å, revealed that the amidinothiophene moiety bound in the S1 pocket and the pyrrolidinone-sulphonamide linker projected the aromatic tail into the S' pocket.
RESUMEN
A solid phase combinatorial library was designed based on X-ray structures and in-silico models to explore an inducible S4+ pocket, which is formed by a simple side-chain rotation of Tyr95. This inducible S4+ pocket is unique to ß-tryptase and does not exist for other trypsin-like serine proteases of interest. Therefore, inhibitors utilizing this pocket have inherent advantages for being selective against other proteases in the same family. A member of this library was found to be a potent and selective ß-tryptase inhibitor with a suitable pharmacokinetic profile for further clinical evaluation.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Mastocitos/enzimología , Bibliotecas de Moléculas Pequeñas/farmacología , Triptasas/antagonistas & inhibidores , Administración Oral , Animales , Técnicas Químicas Combinatorias , Cristalografía por Rayos X , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/administración & dosificación , Inhibidores Enzimáticos/síntesis química , Humanos , Modelos Moleculares , Estructura Molecular , Ratas , Proteínas Recombinantes/antagonistas & inhibidores , Bibliotecas de Moléculas Pequeñas/administración & dosificación , Bibliotecas de Moléculas Pequeñas/síntesis química , Relación Estructura-ActividadRESUMEN
A Comparative Molecular Similarity Indices Analysis (CoMSIA) was performed for 2,6-substituted-4-monosubstituted aminopyrimidine antagonists of prostaglandin D(2) receptor (DP). Both two-component (Q(2) = 0.63, R(2) = 0.82, SEE = 0.47 pIC(50)) and three-component (Q(2) = 0.70, R(2) = 0.91, SEE = 0.36 pIC(50)) CoMSIA models were established. Two hydrogen-bond acceptors with spatial separation of about 8Å are shown as optimal for binding. A large hydrophobic center that separates the two acceptors confers to the potency of the 2,6-substituted-4-monosubstituted aminopyrimidine. The models were used to predict IC(50) values for compounds which had functional groups different from those in the training set.
Asunto(s)
Aminopiridinas/química , Receptores Inmunológicos/antagonistas & inhibidores , Receptores de Prostaglandina/antagonistas & inhibidores , Aminopiridinas/síntesis química , Aminopiridinas/farmacología , Humanos , Enlace de Hidrógeno , Modelos Moleculares , Unión Proteica , Relación Estructura-Actividad Cuantitativa , Receptores Inmunológicos/metabolismo , Receptores de Prostaglandina/metabolismoRESUMEN
Prostanoids play important physiological roles in the cardiovascular and immune systems and in pain sensation in peripheral systems through their interactions with eight G-protein coupled receptors. These receptors are important drug targets, but development of subtype specific agonists and antagonists has been hampered by the lack of 3D structures for these receptors. We report here the 3D structure for the human DP G-protein coupled receptor (GPCR) predicted by the MembStruk computational method. To validate this structure, we use the HierDock computational method to predict the binding mode for the endogenous agonist (PGD2) to DP. Based on our structure, we predicted the binding of different antagonists and optimized them. We find that PGD2 binds vertically to DP in the TM1237 region with the alpha chain toward the extracellular (EC) region and the omega chain toward the middle of the membrane. This structure explains the selectivity of the DP receptor and the residues involved in the predicted binding site correlate very well with available mutation experiments on DP, IP, TP, FP, and EP subtypes. We report molecular dynamics of DP in explicit lipid and water and find that the binding of the PGD2 agonist leads to correlated rotations of helices of TM3 and TM7, whereas binding of antagonist leads to no such rotations. Thus, these motions may be related to the mechanism of activation.
Asunto(s)
Receptores Inmunológicos/química , Receptores de Prostaglandina/química , Secuencia de Aminoácidos , Sitios de Unión , Simulación por Computador , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Lípidos/química , Modelos Moleculares , Datos de Secuencia Molecular , Prostaglandina D2/química , Prostaglandina D2/metabolismo , Conformación Proteica , Receptores Inmunológicos/agonistas , Receptores Inmunológicos/antagonistas & inhibidores , Receptores Inmunológicos/metabolismo , Receptores de Prostaglandina/agonistas , Receptores de Prostaglandina/antagonistas & inhibidores , Receptores de Prostaglandina/metabolismo , Relación Estructura-Actividad , Termodinámica , Agua/químicaRESUMEN
A series of conformationally-restricted analogues of hPTH was prepared, based on the parent peptide agonist, cyclo(Lys(18)-Asp(22))[Ala(1),Nle(8),Lys(18),Asp(22),Leu(27)]hPTH(1-31)NH(2) (2, EC(50)=0.29nM). Truncation of 2 at either the N- or C-termini resulted in peptides with reduced agonist activity as measured by stimulation of adenylate cyclase activity in the rat osteosarcoma cell line (ROS 17/2.8). Alanine- and glycine-scanning at the N-terminus of 2 was consistent with data previously obtained on linear hPTH(1-34). Other locations within the primary sequence of hPTH(1-31)NH(2) were evaluated by the placement of the [i, i+4] lactam constraining element. Ring size and lactam orientations at the 18-22 positions were also examined.