Analysis of the Structure, Substrate Specificity, and Mechanism of Squash Glycerol-3-Phosphate (1)-Acyltransferase

Turnbull, A.P.; Rafferty, John B.; Sedelnikova, Svetlana E.; Slabas, Antoni R.; Schierer, Ted; Kroon, J.; Simon, Jörg; Fawcett, Tony; Nishida, Ikuo; Murata, Norio; Rice, David W.

doi:10.1016/s0969-2126(01)00595-0

Cited by 83 publications

(82 citation statements)

References 25 publications

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“…Because no conserved serine or cysteine residues to which the ␤-ketoacyl moiety attaches are present in Pfam03756 domains, we speculate that AfsA catalyzes the direct ␤-ketoacyl transfer, like the acyl transfer by G3PAT, without forming a ␤-ketoacyl-AfsA complex (22). Serine proteases, thioesterases, and lipases employ an Asp(Glu)-His-Ser catalytic triad for their catalysis; the Asp-His charge relay system increases the nucleophilicity of the Ser, which attacks the substrate to form an acyl-Ser intermediate that is subsequently hydrolyzed.…”

Section: Discussionmentioning

confidence: 99%

Biosynthesis of γ-butyrolactone autoregulators that switch on secondary metabolism and morphological development in Streptomyces

Kato¹,

Funa²,

Watanabe

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

170

207

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A factor (2-isocapryloyl-3R-hydroxymethyl-␥-butyrolactone) is a representative of the ␥-butyrolactone autoregulators that trigger secondary metabolism and morphogenesis in the Gram-positive, filamentous bacterial genus Streptomyces. Here, we report the A factor biosynthesis pathway in Streptomyces griseus. The monomeric AfsA, containing a tandem repeat domain of Ϸ80 aa, catalyzed ␤-ketoacyl transfer from 8-methyl-3-oxononanoyl-acyl carrier protein to the hydroxyl group of dihydroxyacetone phosphate (DHAP), thus producing an 8-methyl-3-oxononanoyl-DHAP ester. The fatty acid ester was nonenzymatically converted to a butenolide phosphate by intramolecular aldol condensation. The butenolide phosphate was then reduced by BprA that was encoded just downstream of afsA. The phosphate group on the resultant butanolide was finally removed by a phosphatase, resulting in formation of A factor. The 8-methyl-3-oxononanoyl-DHAP ester produced by the action of AfsA was also converted to A factor in an alternative way; the phosphate group on the ester was first removed by a phosphatase and the dephosphorylated ester was converted nonenzymatically to a butenolide, which was then reduced by a reductase different from BprA, resulting in A factor. Because introduction of afsA alone into Escherichia coli caused the host to produce a substance having A factor activity, the reductase(s) and phosphatase(s) were not specific to the A factor biosynthesis but commonly present in bacteria. AfsA is thus the key enzyme for the biosynthesis of ␥-butyrolactones.A factor ͉ Streptomyces griseus ͉ AfsA ͉ cell-to-cell signaling

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Section: Discussionmentioning

confidence: 99%

Biosynthesis of γ-butyrolactone autoregulators that switch on secondary metabolism and morphological development in Streptomyces

Kato¹,

Funa²,

Watanabe

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

170

207

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“…allowed the determination of a high-resolution crystal structure of the glycerol-phosphate acyltransferase that informs us concerning the specific functions of the conserved amino acid blocks in this group of proteins (39)(40)(41). Motif 1 containing the HX 4 D motif is oriented with the carboxyl of the aspartate, which is hydrogen bonded to the histidine to leave the nonbonding electron pair on the histidine facing the active site, where the lone electron pair participates in abstracting a proton from the 1-position hydroxyl of glycerol-phosphate to activate this atom for nucleophilic attack on the acyl thioester.…”

Section: Glycerol-3-phosphate Acyltranferasesmentioning

confidence: 99%

Thematic Review Series: Glycerolipids. Acyltransferases in bacterial glycerophospholipid synthesis

Zhang

Rock

2008

Journal of Lipid Research

124

122

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Phospholipid biosynthesis is a vital facet of bacterial physiology that begins with the synthesis of the fatty acids by a soluble type II fatty acid synthase. The bacterial glycerol-phosphate acyltransferases utilize the completed fatty acid chains to form the first membrane phospholipid and thus play a critical role in the regulation of membrane biogenesis. The first bacterial acyltransferase described was PlsB, a glycerol-phosphate acyltransferase. PlsB is a key regulatory point that coordinates membrane phospholipid formation with cell growth and macromolecular synthesis. Phosphatidic acid is then produced by PlsC, a 1-acylglycerolphosphate acyltransferase. These two acyltransferases use thioesters of either CoA or acyl carrier protein (ACP) as the acyl donors and have homologs that perform the same reactions in higher organisms. However, the most prevalent glycerol-phosphate acyltransferase in the bacterial world is PlsY, which uses a recently discovered acyl-phosphate fatty acid intermediate as an acyl donor. This unique activated fatty acid is formed from the acyl-ACP end products of the fatty acid biosynthetic pathway by PlsX, an acyl-ACP:phosphate transacylase. Bacterial phospholipid synthesis is a vital facet of bacterial physiology, and the phospholipid head group structures found in the bacterial world come in a truly bewildering variety (1). Phosphatidic acid is a universal intermediate in the biosynthesis of these membrane glycerophospholipids in eubacteria, and this review focuses on the two acyltransferase steps that are common reactions in all glycerophospholipid biosynthesis in bacteria, the glycerol-phosphate and 1-acylglycerol-phosphate (LPA) acyltransferases. These enzymes sit at the interface between the soluble type II fatty acid biosynthetic pathway and the creation of a phospholipid molecule that drives membrane expansion. This pivotal position makes the glycerol-phosphate acyltransferases key regulators of both fatty acid and phospholipid synthesis and has spurred considerable research into the function, selectivity, and regulation of the acyltransferase systems. This review will cover the two acyltransferase systems involved in bacterial glycerophospholipid synthesis, the origin and utilization of acyl donors by these pathways, and their roles in regulating membrane biogenesis. ACYL DONORS IN ACYLTRANSFERASE REACTIONSThe most important acyl donor in bacterial glycerolipid synthesis is acyl-acyl carrier protein (ACP). ACP is a 9 kDa protein that is the acyl group carrier in type II fatty acid synthesis and shuttles the intermediates attached to the sulfhydryl group at the terminus of its 4′-phosphopantetheine prosthetic group between the pathway enzymes (2, 3). These acyl donors are the end products of the bacterial dissociated type II fatty acid synthesis pathway, and in most bacteria, type II fatty acid synthesis is the sole source of fatty acids for membrane phospholipid synthesis. An acyl-ACP intermediate has two possible fates. It can reenter the fatty acid elongation cycle...

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“…Only a few glycerol lipid acyltransferases have been cloned and sequenced (7)(8)(9)(10)(11). Structural analysis of several glycerolipid acyltransferases from a variety of organisms has revealed a critical domain responsible for their catalytic activity (12).…”

mentioning

confidence: 99%

Identification and characterization of a lysophosphatidylcholine acyltransferase in alveolar type II cells

Chen

Hyatt

Mucenski

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

176

187

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Pulmonary surfactant is a complex of lipids and proteins produced and secreted by alveolar type II cells that provides the low surface tension at the air-liquid interface. The phospholipid most responsible for providing the low surface tension in the lung is dipalmitoylphosphatidylcholine. Dipalmitoylphosphatidylcholine is synthesized in large part by phosphatidylcholine (PC) remodeling, and a lysophosphatidylcholine (lysoPC) acyltransferase is thought to play a critical role in its synthesis. However, this acyltransferase has not yet been identified. We have cloned full-length rat and mouse cDNAs coding for a lysoPC acyltransferase (LPCAT). LPCAT encodes a 535-aa protein of Ϸ59 kDa that contains a transmembrane domain and a putative acyltransferase domain. When transfected into COS-7 cells and HEK293 cells, LPCAT significantly increased lysoPC acyltransferase activity. LPCAT preferred lysoPC as a substrate over lysoPA, lysoPI, lysoPS, lysoPE, or lysoPG and prefers palmitoyl-CoA to oleoyl-CoA as the acyl donor. This LPCAT was preferentially expressed in the lung, specifically within alveolar type II cells. Expression in the fetal lung and in rat type II cells correlated with the expression of the surfactant proteins. LPCAT expression in fetal lung explants was sensitive to dexamethasone and FGFs. KGF was a potent stimulator of LPCAT expression in cultured adult type II cells. We hypothesize that LPCAT plays a critical role in regulating surfactant phospholipid biosynthesis and suggest that understanding the regulation of LPCAT will offer important insight into surfactant phospholipid biosynthesis.biochemistry ͉ lung ͉ surfactant ͉ phosphatidylcholine

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Analysis of the Structure, Substrate Specificity, and Mechanism of Squash Glycerol-3-Phosphate (1)-Acyltransferase

Cited by 83 publications

References 25 publications

Biosynthesis of γ-butyrolactone autoregulators that switch on secondary metabolism and morphological development in Streptomyces

Biosynthesis of γ-butyrolactone autoregulators that switch on secondary metabolism and morphological development in Streptomyces

Thematic Review Series: Glycerolipids. Acyltransferases in bacterial glycerophospholipid synthesis

Identification and characterization of a lysophosphatidylcholine acyltransferase in alveolar type II cells

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