Unique chemical reactivity of His-21 of CRM-197, a mutated diphtheria toxin.
FEBS Lett
; 427(3): 362-6, 1998 May 15.
Article
em En
| MEDLINE
| ID: mdl-9637258
ABSTRACT
CRM-197 is a mutated diphtheria toxin (63000 Da) widely used as a carrier protein of conjugated vaccines. Among the 14 histidines of CRM-197, His-21 was found to be modified selectively with iodoacetamide based reagents. This finding suggests a simplified method for the preparation of conjugate vaccines crosslinked to CRM-197. A bifunctional iodoacetamide, N,N'-(2-hydroxy-1,3-propanediyl)-bis-12-iodoacetamidel (I-CH2-CONH-CH2-CH(OH)-CH2-NHCO-CH2-I) (HPBIA), was synthesized and allowed to react with CRM-197. In the alkaline buffer of pH 8.0-8.4, HPBIA was shown to react and intra-bridge His-21 and Lys-24 of CRM-197 sequentially. At lower pH (7.1-7.5) in the phosphate buffer, the reactivity of Lys-24 toward HPBIA was suppressed drastically. Under these conditions, His-21 could be specifically labeled with HPBIA. Initial experiments have demonstrated that HPBIA modified CRM-197 is able to crosslink to a cysteine-containing peptide. These results offer a potential route for improving the homogeneity of CRM-197 based protein-peptide as well as protein-polysaccharide conjugates.
Buscar no Google
Coleções:
01-internacional
Temas:
Geral
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Bactérias
/
Toxina Diftérica
/
Histidina
Idioma:
En
Revista:
FEBS Lett
Ano de publicação:
1998
Tipo de documento:
Article
País de afiliação:
Suíça