Acyl carrier protein: structure–function relationships in a conserved multifunctional protein family

2007 ◽  
Vol 85 (6) ◽  
pp. 649-662 ◽  
Author(s):  
David M. Byers ◽  
Huansheng Gong

Acyl carrier protein (ACP) is a universal and highly conserved carrier of acyl intermediates during fatty acid synthesis. In yeast and mammals, ACP exists as a separate domain within a large multifunctional fatty acid synthase polyprotein (type I FAS), whereas it is a small monomeric protein in bacteria and plastids (type II FAS). Bacterial ACPs are also acyl donors for synthesis of a variety of products, including endotoxin and acylated homoserine lactones involved in quorum sensing; the distinct and essential nature of these processes in growth and pathogenesis make ACP-dependent enzymes attractive antimicrobial drug targets. Additionally, ACP homologues are key components in the production of secondary metabolites such as polyketides and nonribosomal peptides. Many ACPs exhibit characteristic structural features of natively unfolded proteins in vitro, with a dynamic and flexible conformation dominated by 3 parallel α helices that enclose the thioester-linked acyl group attached to a phosphopantetheine prosthetic group. ACP conformation may also be influenced by divalent cations and interaction with partner enzymes through its “recognition” helix II, properties that are key to its ability to alternately sequester acyl groups and deliver them to the active sites of ACP-dependent enzymes. This review highlights recent progress in defining how the structural features of ACP are related to its multiple carrier roles in fatty acid metabolism.

1996 ◽  
Vol 40 (12) ◽  
pp. 2813-2819 ◽  
Author(s):  
R A Slayden ◽  
R E Lee ◽  
J W Armour ◽  
A M Cooper ◽  
I M Orme ◽  
...  

Thiolactomycin (TLM) possesses in vivo antimycobacterial activity against the saprophytic strain Mycobacterium smegmatis mc2155 and the virulent strain M. tuberculosis Erdman, resulting in complete inhibition of growth on solid media at 75 and 25 micrograms/ml, respectively. Use of an in vitro murine macrophage model also demonstrated the killing of viable intracellular M. tuberculosis in a dose-dependent manner. Through the use of in vivo [1,2-14C]acetate labeling of M. smegmatis, TLM was shown to inhibit the synthesis of both fatty acids and mycolic acids. However, synthesis of the shorter-chain alpha'-mycolates of M. smegmatis was not inhibited by TLM, whereas synthesis of the characteristic longer-chain alpha-mycolates and epoxymycolates was almost completely inhibited at 75 micrograms/ml. The use of M. smegmatis cell extracts demonstrated that TLM specifically inhibited the mycobacterial acyl carrier protein-dependent type II fatty acid synthase (FAS-II) but not the multifunctional type I fatty acid synthase (FAS-I). In addition, selective inhibition of long-chain mycolate synthesis by TLM was demonstrated in a dose-response manner in purified, cell wall-containing extracts of M. smegmatis cells. The in vivo and in vitro data and knowledge of the mechanism of TLM resistance in Escherichia coli suggest that two distinct TLM targets exist in mycobacteria, the beta-ketoacyl-acyl carrier protein synthases involved in FAS-II and the elongation steps leading to the synthesis of the alpha-mycolates and oxygenated mycolates. The efficacy of TLM against M. smegmatis and M. tuberculosis provides the prospects of identifying fatty acid and mycolic acid biosynthetic genes and revealing a novel range of chemotherapeutic agents directed against M. tuberculosis.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Woo Cheol Lee ◽  
Sungjae Choi ◽  
Ahjin Jang ◽  
Kkabi Son ◽  
Yangmee Kim

AbstractSome Gram-negative bacteria harbor lipids with aryl polyene (APE) moieties. Biosynthesis gene clusters (BGCs) for APE biosynthesis exhibit striking similarities with fatty acid synthase (FAS) genes. Despite their broad distribution among pathogenic and symbiotic bacteria, the detailed roles of the metabolic products of APE gene clusters are unclear. Here, we determined the crystal structures of the β-ketoacyl-acyl carrier protein (ACP) reductase ApeQ produced by an APE gene cluster from clinically isolated virulent Acinetobacter baumannii in two states (bound and unbound to NADPH). An in vitro visible absorption spectrum assay of the APE polyene moiety revealed that the β-ketoacyl-ACP reductase FabG from the A. baumannii FAS gene cluster cannot be substituted for ApeQ in APE biosynthesis. Comparison with the FabG structure exhibited distinct surface electrostatic potential profiles for ApeQ, suggesting a positively charged arginine patch as the cognate ACP-binding site. Binding modeling for the aryl group predicted that Leu185 (Phe183 in FabG) in ApeQ is responsible for 4-benzoyl moiety recognition. Isothermal titration and arginine patch mutagenesis experiments corroborated these results. These structure–function insights of a unique reductase in the APE BGC in comparison with FAS provide new directions for elucidating host–pathogen interaction mechanisms and novel antibiotics discovery.


2007 ◽  
Vol 283 (1) ◽  
pp. 518-528 ◽  
Author(s):  
Eliza Ploskoń ◽  
Christopher J. Arthur ◽  
Simon E. Evans ◽  
Christopher Williams ◽  
John Crosby ◽  
...  

2008 ◽  
Vol 190 (9) ◽  
pp. 3147-3154 ◽  
Author(s):  
Kun Zhu ◽  
Charles O. Rock

ABSTRACT Pseudomonas aeruginosa secretes a rhamnolipid (RL) surfactant that functions in hydrophobic nutrient uptake, swarming motility, and pathogenesis. We show that RhlA supplies the acyl moieties for RL biosynthesis by competing with the enzymes of the type II fatty acid synthase (FASII) cycle for the β-hydroxyacyl-acyl carrier protein (ACP) pathway intermediates. Purified RhlA forms one molecule of β-hydroxydecanoyl-β-hydroxydecanoate from two molecules of β-hydroxydecanoyl-ACP and is the only enzyme required to generate the lipid component of RL. The acyl groups in RL are primarily β-hydroxydecanoyl, and in vitro, RhlA has a greater affinity for 10-carbon substrates, illustrating that RhlA functions as a molecular ruler that selectively extracts 10-carbon intermediates from FASII. Eliminating either FabA or FabI activity in P. aeruginosa increases RL production, illustrating that slowing down FASII allows RhlA to more-effectively compete for β-hydroxydecanoyl-ACP. In Escherichia coli, the rate of fatty acid synthesis increases 1.3-fold when RhlA is expressed, to ensure the continued formation of fatty acids destined for membrane phospholipid even though 24% of the carbon entering FASII is diverted to RL synthesis. Previous studies have placed a ketoreductase, called RhlG, before RhlA in the RL biosynthetic pathway; however, our experiments show that RhlG has no role in RL biosynthesis. We conclude that RhlA is necessary and sufficient to form the acyl moiety of RL and that the flux of carbon through FASII accelerates to support RL production and maintain a supply of acyl chains for phospholipid synthesis.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Madeline F. Currie ◽  
Dylan M. Persaud ◽  
Niralee K. Rana ◽  
Amanda J. Platt ◽  
Joris Beld ◽  
...  

Abstract Fatty acids are essential to most organisms and are made endogenously by the fatty acid synthase (FAS). FAS is an attractive target for antibiotics and many inhibitors are in clinical development. However, some gram-negative bacteria harbor an enzyme known as the acyl-acyl carrier protein synthetase (AasS), which allows them to scavenge fatty acids from the environment and shuttle them into FAS and ultimately lipids. The ability of AasS to recycle fatty acids may help pathogenic gram-negative bacteria circumvent FAS inhibition. We therefore set out to design and synthesize an inhibitor of AasS and test its effectiveness on an AasS enzyme from Vibrio harveyi, the most well studied AasS to date, and from Vibrio cholerae, a pathogenic model. The inhibitor C10-AMS [5′-O-(N-decanylsulfamoyl)adenosine], which mimics the tightly bound acyl-AMP reaction intermediate, was able to effectively inhibit AasS catalytic activity in vitro. Additionally, C10-AMS stopped the ability of Vibrio cholerae to recycle fatty acids from media and survive when its endogenous FAS was inhibited with cerulenin. C10-AMS can be used to study fatty acid recycling in other bacteria as more AasS enzymes continue to be annotated and provides a platform for potential antibiotic development.


2018 ◽  
Author(s):  
Emanuele Rossini ◽  
Jan Gajewski ◽  
Maja Klaus ◽  
Gerhard Hummer ◽  
Martin Grininger

ABSTRACTIn the large enzyme complexes of natural biosynthetic pathways, molecules are assembled like in a factory. Carrier domains shuttle substrates and intermediates as covalently attached cargo within the enzyme complex between active sites. The physical confinement of the reaction increases reaction rates and hinders pathway branching. Alternating interactions of substrate-loaded carrier domains with different catalytic domains modulate the chemical environment. In this study, we aim at assessing the impact of domain-domain interactions (DDIs) on the reaction progress of a multienzyme type I fatty acid synthase (FAS) in quantitative terms. We modulate DDIs by single interface mutations, and read out the impact on substrate shuttling by recording fatty acid (FA) chain length product spectra and FAS activities. Our data show that even single interface point mutations can severely affect FA synthesis. With molecular dynamics simulations and modeling, we relate the mutation effects to specific alterations in the molecular interaction networks and domain-domain binding energetics. Some of the presented mutations induce the synthesis of short-chain FAs. These compounds are important commodity products and potent precursors for microbial biofuel production.


2000 ◽  
Vol 28 (6) ◽  
pp. 615-616 ◽  
Author(s):  
G. Honeyman ◽  
T. Fawcett

We have used a yeast two-hybrid approach to detect direct protein interactions between fatty acid synthase components. Enoyl-acyl carrier protein (ACP) reductase was found to interact with stearoyl-ACP desaturase and acyl-ACP thioesterase, but none of these proteins interacted with ACP in the yeast nucleus.


Sign in / Sign up

Export Citation Format

Share Document