Molecular evolution of bacterial beta-lactam resistance.
Chem Biol
; 3(11): 937-47, 1996 Nov.
Article
em En
| MEDLINE
| ID: mdl-8939710
ABSTRACT
BACKGROUND:
Two groups of penicillin-destroying enzymes, the class A and class C beta-lactamases, may have evolved from bacterial transpeptidases that transfer X-D-Ala-D-Ala peptides to the growing peptidoglycan during cell wall synthesis. Both the transpeptidases and the beta-lactamases are acylated by beta-lactam antibiotics such as penicillin, which mimic the peptide, but breakdown and removal of the antibiotic is much faster in the beta-lactamases, which lack the ability to process D-Ala-D-Ala peptides. Stereochemical factors driving this evolution in specificity are examined.RESULTS:
We have compared the crystal structures of two classes of beta-lactamases and a beta-lactam-sensitive D-alanyl-D-alanine carboxy-peptidase/transpeptidase (DD-peptidase). The class C beta-lactamase is more similar to the DD-peptidase than to another beta-lactamase of class A.CONCLUSIONS:
The two classes of beta-lactamases appear to have developed from an ancestral protein along separate evolutionary paths. Structural differentiation of the beta-lactamases from the DD-peptidases appears to follow differences in substrate shapes. The structure of the class A beta-lactamase has been further optimized to exclude D-alanyl peptides and process penicillin substrates with near catalytic perfection.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Bactérias
/
Evolução Molecular
/
Antibacterianos
Idioma:
En
Revista:
Chem Biol
Assunto da revista:
BIOLOGIA
/
BIOQUIMICA
/
QUIMICA
Ano de publicação:
1996
Tipo de documento:
Article
País de afiliação:
Estados Unidos