RESUMO
We present the structure-based optimization of a series of estrogen receptor-beta (ERbeta) selective ligands. X-ray cocrystal structures of these ligands complexed to both ERalpha and ERbeta are described. We also discuss how molecular modeling was used to take advantage of subtle differences between the two binding cavities in order to optimize selectivity for ERbeta over ERalpha. Quantum chemical calculations are utilized to gain insight into the mechanism of selectivity enhancement. Despite only two relatively conservative residue substitutions in the ligand binding pocket, the most selective compounds have greater than 100-fold selectivity for ERbeta relative to ERalpha when measured using a competitive radioligand binding assay.
Assuntos
Receptor beta de Estrogênio/química , Receptor beta de Estrogênio/metabolismo , Sequência de Aminoácidos , Benzofuranos/química , Benzofuranos/metabolismo , Benzoxazóis/química , Benzoxazóis/metabolismo , Sítios de Ligação , Ligação Competitiva , Cristalografia por Raios X , Receptor alfa de Estrogênio/química , Receptor alfa de Estrogênio/metabolismo , Humanos , Ligantes , Masculino , Modelos Moleculares , Dados de Sequência Molecular , Conformação Proteica , Teoria Quântica , Ensaio Radioligante , Relação Estrutura-Atividade , Especificidade por SubstratoAssuntos
Proteínas Ativadoras de GTPase/química , Proteínas de Membrana/química , Proteínas do Tecido Nervoso/química , Ressonância Magnética Nuclear Biomolecular , Sequência de Aminoácidos , Proteínas Ativadoras de GTPase/genética , Humanos , Internet , Isótopos , Proteínas de Membrana/genética , Dados de Sequência Molecular , Proteínas do Tecido Nervoso/genética , Proteínas RGSRESUMO
MAP KAP kinase 2 (MK2), a Ser/Thr kinase, plays a crucial role in the inflammatory process. We have determined the crystal structures of a catalytically active C-terminal deletion form of human MK2, residues 41-364, in complex with staurosporine at 2.7 A and with ADP at 3.2 A, revealing overall structural similarity with other Ser/Thr kinases. Kinetic analysis reveals that the K(m) for ATP is very similar for MK2 41-364 and p38-activated MK2 41-400. Conversely, the catalytic rate and binding for peptide substrate are dramatically reduced in MK2 41-364. However, phosphorylation of MK2 41-364 by p38 restores the V(max) and K(m) for peptide substrate to values comparable to those seen in p38-activated MK2 41-400, suggesting a mechanism for regulation of enzyme activity.
