C-terminal domain mutations in ClpX uncouple substrate binding from an engagement step required for unfolding.
Mol Microbiol
; 48(1): 67-76, 2003 Apr.
Article
em En
| MEDLINE
| ID: mdl-12657045
ClpX mediates ATP-dependent denaturation of specific target proteins and disassembly of protein complexes. Like other AAA + family members, ClpX contains an alphabeta ATPase domain and an alpha-helical C-terminal domain. ClpX proteins with mutations in the C-terminal domain were constructed and screened for disassembly activity in vivo. Seven mutant enzymes with defective phenotypes were purified and characterized. Three of these proteins (L381K, D382K and Y385A) had low activity in disassembly or unfolding assays in vitro. In contrast to wild-type ClpX, substrate binding to these mutants inhibited ATP hydrolysis instead of increasing it. These mutants appear to be defective in a reaction step that engages bound substrate proteins and is required both for enhancement of ATP hydrolysis and for unfolding/disassembly. Some of these side chains form part of the interface between the C-terminal domain of one ClpX subunit and the ATPase domain of an adjacent subunit in the hexamer and appear to be required for communication between adjacent nucleotide binding sites.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Desnaturação Proteica
/
Adenosina Trifosfatases
/
Mutação
Idioma:
En
Revista:
Mol Microbiol
Assunto da revista:
BIOLOGIA MOLECULAR
/
MICROBIOLOGIA
Ano de publicação:
2003
Tipo de documento:
Article
País de afiliação:
Estados Unidos
País de publicação:
Reino Unido