Identification of a histidine residue essential for enzymatic activity of group B streptococcal hyaluronate lyase.
Biochem Biophys Res Commun
; 231(2): 379-82, 1997 Feb 13.
Article
em En
| MEDLINE
| ID: mdl-9070283
ABSTRACT
Hyaluronate lyase produced by group B streptococci (GBS) degrades hyaluronan completely to unsaturated disaccharide units and also cleaves unsulfated regions of chondroitin sulfate. The enzyme is rapidly inactivated by diethyl pyrocarbonate and enzymatic activity is restored by treatment with hydroxylamine, suggesting that a histidine residue is present in the active site. Amino acid sequence comparisons of GBS hyaluronate lyase and four other related enzymes revealed that one of the 16 histidine residues of the enzyme (His-479) is present in a highly conserved region. Conversion of His-479 to a glycine by site-directed mutagenesis resulted in a complete loss of enzymatic activity of the modified protein. We propose that His-479 is in the active site of GBS hyaluronate lyase and participates in the initial abstraction of hydrogen ions from the glucuronic acid residues of hyaluronan.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Polissacarídeo-Liases
/
Streptococcus agalactiae
/
Histidina
Tipo de estudo:
Diagnostic_studies
Idioma:
En
Revista:
Biochem Biophys Res Commun
Ano de publicação:
1997
Tipo de documento:
Article
País de afiliação:
Estados Unidos