Identification of a new active site for autocatalytic processing of penicillin acylase precursor in Escherichia coli ATCC11105.
Biochem Biophys Res Commun
; 272(1): 199-204, 2000 May 27.
Article
em En
| MEDLINE
| ID: mdl-10872827
ABSTRACT
Penicillin acylase (PA) from Escherichia coli ATCC11105 is a periplasmic heterodimer consisting of a 24 kDa small subunit and a 65 kDa large subunit. It is synthesized as a single 96 kDa precursor and then matures to functional PA via a posttranslational processing pathway. The GST-PA fusion protein expression system was established for monitoring the precursor PA processing in vitro. The purified PA precursor was processed into mature PA the same way as in vivo, but pH dependently. From the primary sequence analysis, we identified a putative conserved lysine residue (K299) responsible for the pH dependent processing. The substitution of K299 residue by site-directed mutagenesis affected both the enzyme activity and the precursor PA processing in vivo. Furthermore, it was shown that the processing rates of wild-type and mutant precursor PAs depended on the pKa values of their side chain R group. These results demonstrated that the lysine residue (K299) was involved in the precursor processing of PA together with N-terminal serine residue (S290) of the large subunit.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Penicilina Amidase
/
Precursores Enzimáticos
/
Escherichia coli
Tipo de estudo:
Diagnostic_studies
Idioma:
En
Revista:
Biochem Biophys Res Commun
Ano de publicação:
2000
Tipo de documento:
Article