scholarly journals Decarboxylation of malonyl-(acyl carrier protein) by 3-oxoacyl-(acyl carrier protein) synthases in plant fatty acid biosynthesis

1997 ◽  
Vol 321 (2) ◽  
pp. 313-318 ◽  
Author(s):  
Elke WINTER ◽  
Monika BRUMMEL ◽  
Ricardo SCHUCH ◽  
Friedrich SPENER
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthase ◽  
Fatty Acid Biosynthesis ◽  
Acyl Carrier Protein ◽  
Condensation Reaction ◽  
Simultaneous Increase ◽  
Carrier Protein ◽  
Acid Biosynthesis ◽  
Cuphea Lanceolata ◽  
Reducing Equivalents

In order to identify regulatory steps in fatty acid biosynthesis, the influence of intermediate 3-oxoacyl-(acyl carrier proteins) (3-oxoacyl-ACPs) and end-product acyl-ACPs of the fatty acid synthase reaction on the condensation reaction was investigated in vitro, using total fatty acid synthase preparations and purified 3-oxoacyl-ACP synthases (KASs; EC 2.3.1.41) from Cuphea lanceolata seeds. KAS I and II in the fatty acid synthase preparations were assayed for the elongation of octanoyl- and hexadecanoyl-ACP respectively, and the accumulation of the corresponding condensation product 3-oxoacyl-ACP was studied by modulating the content of the reducing equivalents NADH and NADPH. Complete omission of reducing equivalents resulted with either KAS in the abnormal synthesis of acetyl-ACP from malonyl-ACP by a decarboxylation reaction. Supplementation with NADPH or NADH, separately or in combination with recombinant 3-oxoacyl-ACP reductase (EC 1.1.1.100), led to a decrease in the amount of acetyl-ACP and a simultaneous increase in elongation products. This demonstrates that the accumulation of 3-oxoacyl-ACP inhibits the condensation reaction on the one hand, and induces the decarboxylation of malonyl-ACP on the other. By carrying out similar experiments with purified enzymes, this decarboxylation was attributed to the action of KAS. Our data point to a regulatory mechanism for the degradation of malonyl-ACP in plants which is activated by the accumulation of the fatty acid synthase intermediate 3-oxoacyl-ACP.

scholarly journals β-Ketoacyl-Acyl Carrier Protein Synthase III (FabH) Is a Determining Factor in Branched-Chain Fatty Acid Biosynthesis

2000 ◽  
Vol 182 (2) ◽  
pp. 365-370 ◽  
Author(s):  
Keum-Hwa Choi ◽  
Richard J. Heath ◽  
Charles O. Rock
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthase ◽  
Fatty Acid Biosynthesis ◽  
Acyl Carrier Protein ◽  
Chain Fatty Acid ◽  
Carrier Protein ◽  
Acid Biosynthesis ◽  
Biochemical Basis ◽  
E Coli ◽  
Branched Chain

ABSTRACT A universal set of genes encodes the components of the dissociated, type II, fatty acid synthase system that is responsible for producing the multitude of fatty acid structures found in bacterial membranes. We examined the biochemical basis for the production of branched-chain fatty acids by gram-positive bacteria. Two genes that were predicted to encode homologs of the β-ketoacyl-acyl carrier protein synthase III of Escherichia coli (eFabH) were identified in theBacillus subtilis genome. Their protein products were expressed, purified, and biochemically characterized. Both B. subtilis FabH homologs, bFabH1 and bFabH2, carried out the initial condensation reaction of fatty acid biosynthesis with acetyl-coenzyme A (acetyl-CoA) as a primer, although they possessed lower specific activities than eFabH. bFabH1 and bFabH2 also utilized iso- and anteiso-branched-chain acyl-CoA primers as substrates. eFabH was not able to accept these CoA thioesters. Reconstitution of a complete round of fatty acid synthesis in vitro with purified E. coli proteins showed that eFabH was the only E. colienzyme incapable of using branched-chain substrates. Expression of either bFabH1 or bFabH2 in E. coli resulted in the appearance of a branched-chain 17-carbon fatty acid. Thus, the substrate specificity of FabH is an important determinant of branched-chain fatty acid production.

The role of β-ketoacyl-acyl carrier protein synthase III in the condensation steps of fatty acid biosynthesis in sunflower

Planta ◽  
2010 ◽  
Vol 231 (6) ◽  
pp. 1277-1289 ◽  
Author(s):  
Damián González-Mellado ◽  
Penny von Wettstein-Knowles ◽  
Rafael Garcés ◽  
Enrique Martínez-Force
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Biosynthesis ◽  
Acyl Carrier Protein ◽  
Carrier Protein ◽  
Acid Biosynthesis

scholarly journals Recognition of Intermediate Functionality by Acyl Carrier Protein over a Complete Cycle of Fatty Acid Biosynthesis

2010 ◽  
Vol 17 (7) ◽  
pp. 776-785 ◽  
Author(s):  
Eliza Płoskoń ◽  
Christopher J. Arthur ◽  
Amelia L.P. Kanari ◽  
Pakorn Wattana-amorn ◽  
Christopher Williams ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Biosynthesis ◽  
Acyl Carrier Protein ◽  
Carrier Protein ◽  
Acid Biosynthesis ◽  
Complete Cycle

scholarly journals Elucidation of transient protein-protein interactions within carrier protein-dependent biosynthesis

2020 ◽  
Author(s):  
Michael Burkart ◽  
Thomas Bartholow ◽  
Terra Sztain ◽  
Ashay Patel ◽  
D Lee ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Protein Interactions ◽  
Fatty Acid Biosynthesis ◽  
De Novo ◽  
Acyl Carrier Protein ◽  
Protein Docking ◽  
Carrier Protein ◽  
Protein Protein Interactions ◽  
Acid Biosynthesis ◽  
E Coli

Abstract Fatty acid biosynthesis (FAB) is an essential and highly conserved metabolic pathway. In bacteria, this process is mediated by an elaborate network of protein•protein interactions (PPIs) involving a small, dynamic acyl carrier protein that interacts with dozens of other partner proteins (PPs). These PPIs have remained poorly characterized due to their dynamic and transient nature. Using a combination of solution-phase NMR spectroscopy and protein-protein docking simulations, we report a comprehensive residue-by-residue comparison of the PPIs formed during FAB in Escherichia coli. This work reveals the molecular basis of six discrete binding events responsible for E. coli FAB and offers insights into a method to characterize these events and those in related carrier protein-dependent pathways. ONE SENTENCE SUMMARY: Through a combination of structural and computational analysis, a comparative evaluation of protein-protein interactions in de novo fatty acid biosynthesis in E. coli is performed.

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