2e5a

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spinqualitylabelsall models 2e5a, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Crystal Structure of Bovine Lipoyltransferase in Complex with Lipoyl-AMP

Overview

Lipoic acid is an essential cofactor of the alpha-ketoacid dehydrogenase, complexes and the glycine cleavage system. It is covalently attached to a, specific lysine residue of the subunit of the complexes. The bovine, lipoyltransferase (bLT) catalyzes the lipoic acid attachment reaction, using lipoyl-AMP as a substrate, forming a lipoylated protein and AMP. To, gain insights into the reaction mechanism at the atomic level, we have, determined the crystal structure of bLT at 2.10 A resolution., Unexpectedly, the purified recombinant bLT contains endogenous lipoyl-AMP., The structure of bLT consists of N-terminal and C-terminal domains, and, lipoyl-AMP is bound to the active site in the N-terminal domain, adopting, a U-shaped conformation. The lipoyl moiety is buried in the hydrophobic, pocket, forming van der Waals interactions, and the AMP moiety forms, numerous hydrogen bonds with bLT in another tunnel-like cavity. These, interactions work together to expose the C10 atom of lipoyl-AMP to the, surface of the bLT molecule. The carbonyl oxygen atom of lipoyl-AMP, interacts with the invariant Lys135. The interaction might stimulate the, positive charge of the C10 atom of lipoyl-AMP, and consequently facilitate, the nucleophilic attack by the lysine residue of the lipoate-acceptor, protein, accompanying the bond cleavage between the carbonyl group and the, phosphate group. We discuss the structural differences between bLT and the, lipoate-protein ligase A from Escherichia coli and Thermoplasma, acidophilum. We further demonstrate that bLT in mitochondria also contains, endogenous lipoylmononucleotide, being ready for the lipoylation of, apoproteins.

About this Structure

2E5A is a Single protein structure of sequence from Bos taurus with MG, PO4, LAQ and ACY as ligands. Full crystallographic information is available from OCA.

Reference

Crystal structure of bovine Lipoyltransferase in complex with lipoyl-AMP., Fujiwara K, Hosaka H, Matsuda M, Okamura-Ikeda K, Motokawa Y, Suzuki M, Nakagawa A, Taniguchi H, J Mol Biol. 2007 Aug 3;371(1):222-34. Epub 2007 May 26. PMID:17570395

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