Crystal structure of the Bacillus subtilis penicillin-binding protein 4a, and its complex with a peptidoglycan mimetic peptide.
J Mol Biol
; 371(2): 528-39, 2007 Aug 10.
Article
em En
| MEDLINE
| ID: mdl-17582436
ABSTRACT
The genome of Bacillus subtilis encodes 16 penicillin-binding proteins (PBPs) involved in the synthesis and/or remodelling of the peptidoglycan during the complex life cycle of this sporulating Gram-positive rod-shaped bacterium. PBP4a (encoded by the dacC gene) is a low-molecular mass PBP clearly exhibiting in vitro DD-carboxypeptidase activity. We have solved the crystal structure of this protein alone and in complex with a peptide (D-alpha-aminopymelyl-epsilon-D-alanyl-D-alanine) that mimics the C-terminal end of the Bacillus peptidoglycan stem peptide. PBP4a is composed of three domains the penicillin-binding domain with a fold similar to the class A beta-lactamase structure and two domains inserted between the conserved motifs 1 and 2 characteristic of the penicillin-recognizing enzymes. The soaking of PBP4a in a solution of D-alpha-aminopymelyl-epsilon-D-alanyl-D-alanine resulted in an adduct between PBP4a and a D-alpha-aminopimelyl-epsilon-D-alanine dipeptide and an unbound D-alanine, i.e. the products of acylation of PBP4a by D-alpha-aminopymelyl-epsilon-D-alanyl-D-alanine with the release of a D-alanine. The adduct also reveals a binding pocket specific to the diaminopimelic acid, the third residue of the peptidoglycan stem pentapeptide of B. subtilis. This pocket is specific for this class of PBPs.
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Base de dados:
MEDLINE
Assunto principal:
Peptídeos
/
Bacillus subtilis
/
Peptidoglicano
/
Materiais Biomiméticos
/
Proteínas de Ligação às Penicilinas
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
Idioma:
En
Ano de publicação:
2007
Tipo de documento:
Article