Structural highlights
Function
[LPLAN_THEAC] Part of a lipoate-protein ligase complex that catalyzes both the ATP-dependent activation of exogenously supplied lipoate to lipoyl-AMP and the transfer of the activated lipoyl onto the lipoyl domains of lipoate-dependent enzymes. Can also use octanoate as substrate.[1] [2] [3]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Lipoyl-lysine swinging arms are crucial to the reactions catalysed by the 2-oxo acid dehydrogenase multienzyme complexes. A gene encoding a putative lipoate protein ligase (LplA) of Thermoplasma acidophilum was cloned and expressed in Escherichia coli. The recombinant protein, a monomer of molecular mass 29 kDa, was catalytically inactive. Crystal structures in the absence and presence of bound lipoic acid were solved at 2.1 A resolution. The protein was found to fall into the alpha/beta class and to be structurally homologous to the catalytic domains of class II aminoacyl-tRNA synthases and biotin protein ligase, BirA. Lipoic acid in LplA was bound in the same position as biotin in BirA. The structure of the T.acidophilum LplA and limited proteolysis of E.coli LplA together highlighted some key features of the post-translational modification. A loop comprising residues 71-79 in the T.acidophilum ligase is proposed as interacting with the dithiolane ring of lipoic acid and discriminating against the entry of biotin. A second loop comprising residues 179-193 was disordered in the T.acidophilum structure; tryptic cleavage of the corresponding loop in the E.coli LplA under non-denaturing conditions rendered the enzyme catalytically inactive, emphasizing its importance. The putative LplA of T.acidophilum lacks a C-terminal domain found in its counterparts in E.coli (Gram-negative) or Streptococcus pneumoniae (Gram-positive). A gene encoding a protein that appears to have structural homology to the additional domain in the E.coli and S.pneumoniae enzymes was detected alongside the structural gene encoding the putative LplA in the T.acidophilum genome. It is likely that this protein is required to confer activity on the LplA as currently purified, one protein perhaps catalysing the formation of the obligatory lipoyl-AMP intermediate, and the other transferring the lipoyl group from it to the specific lysine residue in the target protein.
Structure of a putative lipoate protein ligase from Thermoplasma acidophilum and the mechanism of target selection for post-translational modification.,McManus E, Luisi BF, Perham RN J Mol Biol. 2006 Feb 24;356(3):625-37. Epub 2005 Dec 5. PMID:16384580[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Kim DJ, Kim KH, Lee HH, Lee SJ, Ha JY, Yoon HJ, Suh SW. Crystal structure of lipoate-protein ligase A bound with the activated intermediate: insights into interaction with lipoyl domains. J Biol Chem. 2005 Nov 11;280(45):38081-9. Epub 2005 Sep 2. PMID:16141198 doi:10.1074/jbc.M507284200
- ↑ Christensen QH, Cronan JE. The Thermoplasma acidophilum LplA-LplB complex defines a new class of bipartite lipoate-protein ligases. J Biol Chem. 2009 Aug 7;284(32):21317-26. doi: 10.1074/jbc.M109.015016. Epub 2009, Jun 11. PMID:19520844 doi:http://dx.doi.org/10.1074/jbc.M109.015016
- ↑ Posner MG, Upadhyay A, Bagby S, Hough DW, Danson MJ. A unique lipoylation system in the Archaea. Lipoylation in Thermoplasma acidophilum requires two proteins. FEBS J. 2009 Aug;276(15):4012-22. doi: 10.1111/j.1742-4658.2009.07110.x. Epub, 2009 Jul 7. PMID:19594830 doi:http://dx.doi.org/10.1111/j.1742-4658.2009.07110.x
- ↑ McManus E, Luisi BF, Perham RN. Structure of a putative lipoate protein ligase from Thermoplasma acidophilum and the mechanism of target selection for post-translational modification. J Mol Biol. 2006 Feb 24;356(3):625-37. Epub 2005 Dec 5. PMID:16384580 doi:10.1016/j.jmb.2005.11.057
