scholarly journals In Vivo Evidence that S-Adenosylmethionine and Fatty Acid Synthesis Intermediates Are the Substrates for the LuxI Family of Autoinducer Synthases

1998 ◽  
Vol 180 (10) ◽  
pp. 2644-2651 ◽  
Author(s):  
Dale L. Val ◽  
John E. Cronan
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Acyl Carrier Protein ◽  
Acyl Chain ◽  
Acid Synthesis ◽  
Homoserine Lactone ◽  
Fatty Acid Degradation ◽  
Acid Degradation ◽  
Acyl Coenzyme A

ABSTRACT Many gram-negative bacteria synthesize N-acyl homoserine lactone autoinducer molecules as quorum-sensing signals which act as cell density-dependent regulators of gene expression. We have investigated the in vivo source of the acyl chain and homoserine lactone components of the autoinducer synthesized by the LuxI homolog, TraI. In Escherichia coli, synthesis ofN-(3-oxooctanoyl)homoserine lactone by TraI was unaffected in a fadD mutant blocked in β-oxidative fatty acid degradation. Also, conditions known to induce the fadregulon did not increase autoinducer synthesis. In contrast, cerulenin and diazoborine, specific inhibitors of fatty acid synthesis, both blocked autoinducer synthesis even in a strain dependent on β-oxidative fatty acid degradation for growth. These data provide the first in vivo evidence that the acyl chains in autoinducers synthesized by LuxI-family synthases are derived from acyl-acyl carrier protein substrates rather than acyl coenzyme A substrates. Also, we show that decreased levels of intracellularS-adenosylmethionine caused by expression of bacteriophage T3 S-adenosylmethionine hydrolase result in a marked reduction in autoinducer synthesis, thus providing direct in vivo evidence that the homoserine lactone ring of LuxI-family autoinducers is derived from S-adenosylmethionine.

scholarly journals Fatty acid elongation by a particulate fraction from germinating pea

1980 ◽  
Vol 191 (3) ◽  
pp. 791-797 ◽  
Author(s):  
B R Jordan ◽  
J L Harwood
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
High Speed ◽  
Saturated Fatty Acids ◽  
Acyl Chain ◽  
Fatty Acid Synthetase ◽  
Acid Synthesis ◽  
Particulate Fraction

The synthesis of fatty acids from [14C]malonyl-CoA was studied with a high-speed particulate fraction from germinating pea (Pisum sativum). The variety used (Feltham First) produced mainly saturated fatty acids with palmitate (30–40%) and stearate (40–60%) predominating. Several palmitate-containing lipids stimulated overall synthesis and, in addition, increased the percentage of label in stearate. The production of stearate was severely inhibited by preincubation of the microsomal fraction with snake venom phospholipase A2 or by incubation with Rhizopus arrhizus lipase. Addition of a series of di-saturated phosphatidylcholines, with different acyl constituents, resulted in stimulation of overall fatty acid synthesis as well as an increase in the radiolabelling of the fatty acid two carbon atoms longer than the acyl chain added. This chain lengthening of fatty acids donated from phosphatidylcholine was due to the action of both fatty acid synthetase and palmitate elongase. The latter would utilize dipalmitoyl phosphatidylcholine and was sensitive to arsenite whereas fatty acid synthetase would use dilauroyl phosphatidylcholine and was sensitive to cerulenin. The results are discussed in relation to previous data obtained in vivo on plant fatty acid synthesis and current suggestions for the role of phosphatidylcholine in this process.

scholarly journals Divergent acyl carrier protein decouples mitochondrial Fe-S cluster biogenesis from fatty acid synthesis in malaria parasites

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Seyi Falekun ◽  
Jaime Sepulveda ◽  
Yasaman Jami-Alahmadi ◽  
Hahnbeom Park ◽  
James A Wohlschlegel ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Acyl Carrier Protein ◽  
Acyl Chain ◽  
Acid Synthesis ◽  
Complex Iii ◽  
Carrier Protein ◽  
Prosthetic Group ◽  
Malaria Parasites ◽  
Mitochondrial Fatty Acid

Most eukaryotic cells retain a mitochondrial fatty acid synthesis (FASII) pathway whose acyl carrier protein (mACP) and 4-phosphopantetheine (Ppant) prosthetic group provide a soluble scaffold for acyl chain synthesis and biochemically couple FASII activity to mitochondrial electron transport chain (ETC) assembly and Fe-S cluster biogenesis. In contrast, the mitochondrion of Plasmodium falciparum malaria parasites lacks FASII enzymes yet curiously retains a divergent mACP lacking a Ppant group. We report that ligand-dependent knockdown of mACP is lethal to parasites, indicating an essential FASII-independent function. Decyl-ubiquinone rescues parasites temporarily from death, suggesting a dominant dysfunction of the mitochondrial ETC. Biochemical studies reveal that Plasmodium mACP binds and stabilizes the Isd11-Nfs1 complex required for Fe-S cluster biosynthesis, despite lacking the Ppant group required for this association in other eukaryotes, and knockdown of parasite mACP causes loss of Nfs1 and the Rieske Fe-S protein in ETC Complex III. This work reveals that Plasmodium parasites have evolved to decouple mitochondrial Fe-S cluster biogenesis from FASII activity, and this adaptation is a shared metabolic feature of other apicomplexan pathogens, including Toxoplasma and Babesia. This discovery unveils an evolutionary driving force to retain interaction of mitochondrial Fe-S cluster biogenesis with ACP independent of its eponymous function in FASII.

scholarly journals The mitochondrial acyl carrier protein (ACP) coordinates mitochondrial fatty acid synthesis with iron sulfur cluster biogenesis

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Jonathan G Van Vranken ◽  
Mi-Young Jeong ◽  
Peng Wei ◽  
Yu-Chan Chen ◽  
Steven P Gygi ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Acyl Carrier Protein ◽  
Acyl Chain ◽  
Acid Synthesis ◽  
Carrier Protein ◽  
Iron Sulfur Cluster ◽  
Sulfur Cluster ◽  
Iron Sulfur ◽  
Mitochondrial Fatty Acid

Mitochondrial fatty acid synthesis (FASII) and iron sulfur cluster (FeS) biogenesis are both vital biosynthetic processes within mitochondria. In this study, we demonstrate that the mitochondrial acyl carrier protein (ACP), which has a well-known role in FASII, plays an unexpected and evolutionarily conserved role in FeS biogenesis. ACP is a stable and essential subunit of the eukaryotic FeS biogenesis complex. In the absence of ACP, the complex is destabilized resulting in a profound depletion of FeS throughout the cell. This role of ACP depends upon its covalently bound 4’-phosphopantetheine (4-PP)-conjugated acyl chain to support maximal cysteine desulfurase activity. Thus, it is likely that ACP is not simply an obligate subunit but also exploits the 4-PP-conjugated acyl chain to coordinate mitochondrial fatty acid and FeS biogenesis.

scholarly journals Response of Bacillus subtilis to Cerulenin and Acquisition of Resistance

2001 ◽  
Vol 183 (10) ◽  
pp. 3032-3040 ◽  
Author(s):  
Gustavo E. Schujman ◽  
Keum-Hwa Choi ◽  
Silvia Altabe ◽  
Charles O. Rock ◽  
Diego de Mendoza
Keyword(s):  
Bacillus Subtilis ◽  
Fatty Acid ◽  
Reporter Gene ◽  
Fatty Acid Synthesis ◽  
Acyl Carrier Protein ◽  
Acyl Chain ◽  
Acid Synthesis ◽  
Covalent Modification ◽  
Chain Elongation ◽  
Growth Defect

ABSTRACT Cerulenin is a fungal mycotoxin that potently inhibits fatty acid synthesis by covalent modification of the active site thiol of the chain-elongation subtypes of β-ketoacyl-acyl carrier protein (ACP) synthases. The Bacillus subtilis fabF (yjaY) gene (fabFb ) encodes an enzyme that catalyzes the condensation of malonyl-ACP with acyl-ACP to extend the growing acyl chain by two carbons. There were two mechanisms by which B. subtilis adapted to exposure to this antibiotic. First, reporter gene analysis demonstrated that transcription of the operon containing the fabF gene increased eightfold in response to a cerulenin challenge. This response was selective for the inhibition of fatty acid synthesis, since triclosan, an inhibitor of enoyl-ACP reductase, triggered an increase in fabF reporter gene expression while nalidixic acid did not. Second, spontaneous mutants arose that exhibited a 10-fold increase in the MIC of cerulenin. The mutation mapped at the B. subtilis fabF locus, and sequence analysis of the mutant fabF allele showed that a single base change resulted in the synthesis of FabFb[I108F]. The purified FabFb and FabFb[I108F] proteins had similar specific activities with myristoyl-ACP as the substrate. FabFb exhibited a 50% inhibitory concentration (IC50) of cerulenin of 0.1 μM, whereas the IC50 for FabFb[I108] was 50-fold higher (5 μM). These biochemical data explain the absence of an overt growth defect coupled with the cerulenin resistance phenotype of the mutant strain.

TetR-family transcriptional repressor Thermus thermophilus FadR controls fatty acid degradation

Microbiology ◽  
2011 ◽  
Vol 157 (6) ◽  
pp. 1589-1601 ◽  
Author(s):  
Yoshihiro Agari ◽  
Kazuko Agari ◽  
Keiko Sakamoto ◽  
Seiki Kuramitsu ◽  
Akeo Shinkai
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Target Genes ◽  
Thermus Thermophilus ◽  
Acyl Chain ◽  
Metabolic Energy ◽  
Straight Chain ◽  
Fatty Acid Degradation ◽  
Acid Degradation

In the extremely thermophilic bacterium Thermus thermophilus HB8, one of the four TetR-family transcriptional regulators, which we named T. thermophilus FadR, negatively regulated the expression of several genes, including those involved in fatty acid degradation, both in vivo and in vitro. T. thermophilus FadR repressed the expression of the target genes by binding pseudopalindromic sequences covering the predicted −10 hexamers of their promoters, and medium-to-long straight-chain (C10–18) fatty acyl-CoA molecules were effective for transcriptional derepression. An X-ray crystal structure analysis revealed that T. thermophilus FadR bound one lauroyl (C12)-CoA molecule per FadR monomer, with its acyl chain moiety in the centre of the FadR molecule, enclosed within a tunnel-like substrate-binding pocket surrounded by hydrophobic residues, and the CoA moiety interacting with basic residues on the protein surface. The growth of T. thermophilus HB8, with palmitic acid as the sole carbon source, increased the expression of FadR-regulated genes. These results indicate that in T. thermophilus HB8, medium-to-long straight-chain fatty acids can be used for metabolic energy under the control of FadR, although the major fatty acids found in this strain are iso- and anteiso-branched-chain (C15 and 17) fatty acids.

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