Designing protein dimerizers: the importance of ligand conformational equilibria.
J Am Chem Soc
; 125(6): 1501-7, 2003 Feb 12.
Article
em En
| MEDLINE
| ID: mdl-12568609
ABSTRACT
In an effort to elucidate the role of ligand conformation in induced protein dimerization, we synthesized a flexible methotrexate (MTX) dimer, demonstrated its ability to selectively dimerize Escherichia coli dihydrofolate reductase (DHFR), and evaluated the factors regulating its ability to induce cooperative dimerization. Despite known entropic barriers, bis-MTX proved to possess substantial conformational stability in aqueous solution (-3.8 kcal/mol >/= DeltaG(fold) >/= -4.9 kcal/mol), exerting a dominant influence on the thermodynamics of dimerization. To dimerize DHFR, bis-MTX must shift from a folded to an extended conformation. From this conclusion, the strength of favorable protein-protein interactions in bis-MTX-E. coli DHFR dimers (-3.1 kcal/mol >/= DeltaG(c) >/= -4.2 kcal/mol), and the selectivity of dimerization for E. coli DHFR relative to mouse DHFR (>10(7)) could be determined. The crystal structure of bis-MTX in complex with E. coli DHFR confirms the feasibility of a close-packed dimerization interface and suggests a possible solution conformation for the induced protein dimers. Consequently, the secondary structure of this minimal foldamer regulates its ability to dimerize dihydrofolate reductase in solution, providing insight into the complex energy landscape of induced dimerization.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tetra-Hidrofolato Desidrogenase
/
Metotrexato
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
J Am Chem Soc
Ano de publicação:
2003
Tipo de documento:
Article
País de afiliação:
Estados Unidos