Crystal structure of lipoate-protein ligase A from Escherichia coli. Determination of the lipoic acid-binding site

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...

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Bibliographic Details
Published in:The Journal of biological chemistry 2005-09, Vol.280 (39), p.33645-33651
Main Authors: Fujiwara, Kazuko, Toma, Sachiko, Okamura-Ikeda, Kazuko, Motokawa, Yutaro, Nakagawa, Atsushi, Taniguchi, Hisaaki
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Binding Sites
Conserved Sequence
Crystallography, X-Ray
Escherichia coli
Escherichia coli - chemistry
Escherichia coli - enzymology
Escherichia coli Proteins - chemistry
Escherichia coli Proteins - metabolism
Hydrogen Bonding
Kinetics
Ligases - chemistry
Models, Molecular
Molecular Sequence Data
Mutation
Protein Folding
Protein Structure, Secondary
Protein Structure, Tertiary
Sequence Homology, Amino Acid
Spectrum Analysis, Raman
Thioctic Acid - chemistry
Thioctic Acid - genetics
Thioctic Acid - metabolism
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Summary: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.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M505010200