Functions of characteristic Cys-Gly-His-Cys (CGHC) and Gln-Glu-Asp-Leu (QEDL) motifs of microsomal ER-60 protease.
J Biochem
; 122(4): 834-42, 1997 Oct.
Article
em En
| MEDLINE
| ID: mdl-9399589
ABSTRACT
The human ER-60 protease cDNA was expressed in Escherichia coli BL21 (DE3) cells using the pET-20b(+) T7 promoter. The recombinant ER-60 protease was obtained in a water-soluble form and purified through four sequential chromatographies. The ER-60 protease contains two CGHC motifs. When an alanine residue was substituted for the N-terminal cysteine residue in both motifs, the protease activity was not lost. However, when the C-terminal cysteine residue in both motifs was replaced by a serine residue, the cysteine protease activity, which was inhibited by p-chloromercuribenzoic acid (pCMB) but not by diisopropyl fluorophosphate (DFP), changed to serine protease activity, which was inhibited by DFP but not by pCMB. These results indicate that the C-terminal cysteine residue(s) of the CGHC motifs may constitute the active site(s) of ER-60 protease. The ER-60 protease has a C-terminal QEDL sequence, which was proved to serve as an ER-retention signal by deletion of the QEDL sequence. However, because QEDL could not serve as the ER-retention signal for protein disulfide isomerase or ERp72, it is suggested that amino acid residue(s) of ER-60 protease, other than the QEDL sequence itself, is complimentarily responsible for the ER retention of this protein.
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Coleções:
01-internacional
Contexto em Saúde:
3_ND
Base de dados:
MEDLINE
Assunto principal:
Cisteína Endopeptidases
/
Microssomos
Limite:
Animals
/
Humans
Idioma:
En
Revista:
J Biochem
Ano de publicação:
1997
Tipo de documento:
Article