Crystal structure of lipoate-protein ligase A from Escherichia coli: Determination of the lipoic acid-binding siteFujiwara, K., Toma, S., Okamura-Ikeda, K., Motokawa, Y., Nakagawa, A., Taniguchi, H.
(2005) J Biol Chem 280: 33645-33651
- PubMed: 16043486
- DOI: https://doi.org/10.1074/jbc.M505010200
- Primary Citation of Related Structures:
- PubMed 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.
Institute for Enzyme Research, the University of Tokushima, Tokushima 770-8503, Japan. firstname.lastname@example.org