Crystal structure of lipoate-protein ligase A from Escherichia coli. Determination of the lipoic acid-binding site.
J Biol Chem
; 280(39): 33645-51, 2005 Sep 30.
Article
em En
| MEDLINE
| ID: mdl-16043486
ABSTRACT
Lipoate-protein ligase A (LplA) catalyzes the formation of lipoyl-AMP from lipoate and ATP and then transfers the lipoyl moiety to a specific lysine residue on the acyltransferase subunit of alpha-ketoacid dehydrogenase complexes and on H-protein of the glycine cleavage system. The lypoyllysine arm plays a pivotal role in the complexes by shuttling the reaction intermediate and reducing equivalents between the active sites of the components of the complexes. We have determined the X-ray crystal structures of Escherichia coli LplA alone and in a complex with lipoic acid at 2.4 and 2.9 angstroms resolution, respectively. The structure of LplA consists of a large N-terminal domain and a small C-terminal domain. The structure identifies the substrate binding pocket at the interface between the two domains. Lipoic acid is bound in a hydrophobic cavity in the N-terminal domain through hydrophobic interactions and a weak hydrogen bond between carboxyl group of lipoic acid and the Ser-72 or Arg-140 residue of LplA. No large conformational change was observed in the main chain structure upon the binding of lipoic acid.
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Coleções:
01-internacional
Contexto em Saúde:
3_ND
Base de dados:
MEDLINE
Assunto principal:
Ácido Tióctico
/
Cristalografia por Raios X
/
Proteínas de Escherichia coli
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Escherichia coli
/
Ligases
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
2005
Tipo de documento:
Article