RESUMEN
We have previously shown that the thermolabile, cavity-creating p53 cancer mutant Y220C can be reactivated by small-molecule stabilizers. In our ongoing efforts to unearth druggable variants of the p53 mutome, we have now analyzed the effects of other cancer-associated mutations at codon 220 on the structure, stability, and dynamics of the p53 DNA-binding domain (DBD). We found that the oncogenic Y220H, Y220N, and Y220S mutations are also highly destabilizing, suggesting that they are largely unfolded under physiological conditions. A high-resolution crystal structure of the Y220S mutant DBD revealed a mutation-induced surface crevice similar to that of Y220C, whereas the corresponding pocket's accessibility to small molecules was blocked in the structure of the Y220H mutant. Accordingly, a series of carbazole-based small molecules, designed for stabilizing the Y220C mutant, also bound to and stabilized the folded state of the Y220S mutant, albeit with varying affinities due to structural differences in the binding pocket of the two mutants. Some of the compounds also bound to and stabilized the Y220N mutant, but not the Y220H mutant. Our data validate the Y220S and Y220N mutants as druggable targets and provide a framework for the design of Y220S or Y220N-specific compounds as well as compounds with dual Y220C/Y220S specificity for use in personalized cancer therapy.
Asunto(s)
Antineoplásicos/química , Carbazoles/química , Proteínas Mutantes/química , Proteínas Mutantes/genética , Proteína p53 Supresora de Tumor/química , Proteína p53 Supresora de Tumor/genética , Antineoplásicos/farmacología , Carbazoles/farmacología , Cristalización , Ensayos de Selección de Medicamentos Antitumorales , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Modelos Moleculares , Mutación , Unión Proteica , Dominios Proteicos , Estabilidad Proteica/efectos de los fármacos , Relación Estructura-ActividadRESUMEN
Combined photochemical arylation, "nuisance effect" (SN Ar) reaction sequences have been employed in the design of small arrays for immediate deployment in medium-throughput X-ray protein-ligand structure determination. Reactions were deliberately allowed to run "out of control" in terms of selectivity; for example the ortho-arylation of 2-phenylpyridine gave five products resulting from mono- and bisarylations combined with SN Ar processes. As a result, a number of crystallographic hits against NUDT7, a key peroxisomal CoA ester hydrolase, have been identified.