Crystal structure of ARF1*Sec7 complexed with Brefeldin A and its implications for the guanine nucleotide exchange mechanism.
Mol Cell
; 12(6): 1403-11, 2003 Dec.
Article
em En
| MEDLINE
| ID: mdl-14690595
ABSTRACT
ARF GTPases are activated by guanine nucleotide exchange factors (GEFs) of the Sec7 family that promote the exchange of GDP for GTP. Brefeldin A (BFA) is a fungal metabolite that binds to the ARF1*GDP*Sec7 complex and blocks GEF activity at an early stage of the reaction, prior to guanine nucleotide release. The crystal structure of the ARF1*GDP*Sec7*BFA complex shows that BFA binds at the protein-protein interface to inhibit conformational changes in ARF1 required for Sec7 to dislodge the GDP molecule. Based on a comparative analysis of the inhibited complex, nucleotide-free ARF1*Sec7 and ARF1*GDP, we suggest that, in addition to forcing nucleotide release, the ARF1-Sec7 binding energy is used to open a cavity on ARF1 to facilitate the rearrangement of hydrophobic core residues between the GDP and GTP conformations. Thus, the Sec7 domain may act as a dual catalyst, facilitating both nucleotide release and conformational switching on ARF proteins.
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Base de dados:
MEDLINE
Assunto principal:
Inibidores da Síntese de Proteínas
/
Brefeldina A
/
Fator 1 de Ribosilação do ADP
/
Fatores de Troca do Nucleotídeo Guanina
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Estrutura Quaternária de Proteína
/
Guanosina Difosfato
Idioma:
En
Ano de publicação:
2003
Tipo de documento:
Article