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PROSITE documentation PDOC01017 [for PROSITE entry PS01313]

LipB octanoyltransferase signature


Octanoyl-[acyl-carrier-protein]-protein N-octanoyltransferase [1] (gene lipB) is the bacterial enzyme that transfers the octanoyl moiety of octanoyl-acyl carrier protein (octanoyl-ACP) to the lipoyl domains of the 2-oxoacid deshydrogenases and the H subunit of glycine cleavage enzyme.

via a thioester-linked octanoyl-LipBintermediate [zhao].

The Escherichia coli LipB reaction proceeds through an acyl-enzyme intermediate in which octanoate is first transferred from the thiol of ACP to a specific LipB thiol. The acyl-enzyme thioester bond is then attacked by the epsilon-amino group of the lipoyl domain lysine residue, resulting in the amide-linked octanoylated domains that are the substrates for sulfur insertion.

LipB shows no obvious sequence relatedness to proteins other than its homologues which are widely distributed among prokaryotic and eukaryotic organisms.

Such an enzyme has also be found in fungi [2], where it is located in the mitochondria. It also seems to exist in plants and is encoded in the chloroplast genome of the red alga Cyanidium caldarium.

As a signature for lipB, we selected the most conserved region, located in the central part of the enzyme. This region contains one of two conserved histidines.

Last update:

April 2006 / Pattern revised.


Technical section

PROSITE method (with tools and information) covered by this documentation:

LIPB, PS01313; Lipoate-protein ligase B signature  (PATTERN)


1AuthorsMorris T.W. Reed K.E. Cronan J.E. Jr.
TitleLipoic acid metabolism in Escherichia coli: the lplA and lipB genes define redundant pathways for ligation of lipoyl groups to apoprotein.
SourceJ. Bacteriol. 177:1-10(1995).
PubMed ID8002607

?AuthorsZhao X. Miller J.R. Cronan J.E.
TitleThe reaction of LipB, the octanoyl-[acyl carrier protein]:protein N-octanoyltransferase of lipoic acid synthesis, proceeds through an acyl-enzyme intermediate.
SourceBiochemistry 44:16737-16746(2005).
PubMed ID16342964

2AuthorsChen X.J.
TitleCloning and characterization of the lipoyl-protein ligase gene LIPB from the yeast Kluyveromyces lactis: synergistic respiratory deficiency due to mutations in LIPB and mitochondrial F1-ATPase subunits.
SourceMol. Gen. Genet. 255:341-349(1997).
PubMed ID9268025

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