1w66
Structure of a lipoate-protein ligase b from Mycobacterium tuberculosis
Structural highlights
FunctionLIPB_MYCTU Catalyzes the transfer of endogenously produced octanoic acid from octanoyl-acyl-carrier-protein onto the lipoyl domains of lipoate-dependent enzymes. Lipoyl-ACP can also act as a substrate although octanoyl-ACP is likely to be the physiological substrate.[HAMAP-Rule:MF_00013][1] 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 PubMedLipoic acid is essential for the activation of a number of protein complexes involved in key metabolic processes. Growth of Mycobacterium tuberculosis relies on a pathway in which the lipoate attachment group is synthesized from an endogenously produced octanoic acid moiety. In patients with multiple-drug-resistant M. tuberculosis, expression of one gene from this pathway, lipB, encoding for octanoyl-[acyl carrier protein]-protein acyltransferase is considerably up-regulated, thus making it a potential target in the search for novel antiinfectives against tuberculosis. Here we present the crystal structure of the M. tuberculosis LipB protein at atomic resolution, showing an unexpected thioether-linked active-site complex with decanoic acid. We provide evidence that the transferase functions as a cysteine/lysine dyad acyltransferase, in which two invariant residues (Lys-142 and Cys-176) are likely to function as acid/base catalysts. Analysis by MS reveals that the LipB catalytic reaction proceeds by means of an internal thioesteracyl intermediate. Structural comparison of LipB with lipoate protein ligase A indicates that, despite conserved structural and sequence active-site features in the two enzymes, 4'-phosphopantetheine-bound octanoic acid recognition is a specific property of LipB. The Mycobacterium tuberculosis LipB enzyme functions as a cysteine/lysine dyad acyltransferase.,Ma Q, Zhao X, Nasser Eddine A, Geerlof A, Li X, Cronan JE, Kaufmann SH, Wilmanns M Proc Natl Acad Sci U S A. 2006 Jun 6;103(23):8662-7. Epub 2006 May 30. PMID:16735476[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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