The type I rat fatty acid synthase ACP shows structural homology and analogous biochemical properties to type II ACPs

Reed, Michelle A.C.; Schweizer, Michael; Szafranska, Anna E.; Arthur, Christopher J.; Nicholson, Thomas P.; Cox, Russell J.; Crosby, John; Crump, Matthew P.; Simpson, Thomas J.

doi:10.1039/b208941f

Cited by 44 publications

(67 citation statements)

References 49 publications

(85 reference statements)

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“…15 13 C HSQC data sets were acquired (15). These spectra supplemented the 15 N-edited NOESY-HSQC and TOCSY-HSQC spectra gained previously (10). All spectra were processed and viewed with NMRPipe (16) and CcpN Analysis (17,18 15 N]-labeled rat FAS apoACP.…”

Section: Methodsmentioning

confidence: 99%

“…15 N-Labeled and 15 N-13 C double labeled rat FAS apoACP were overexpressed and purified in a similar fashion to that described previously (10). Routinely, 5-10 mg/liter of 15 N-labeled and 3-5 mg/liter of 15 N-13 C double labeled rat FAS ACP was obtained.…”

Section: Structure Of Rat Fas Apoacp-mentioning

confidence: 99%

“…We have previously reported the low resolution solution phase structure of the isolated rat FAS apoACP domain (10) and found it to adopt an ␣ helical bundle structure consistent with the Type II ACPs from fatty acid (11) and polyketide synthases (PKSs) (12). Furthermore, it has been shown that the rat FAS ACP can sub-stitute for the E. coli FAS ACP (13) in vivo and that it is recognized as a substrate by enzymes known to modify Type II ACPs including Streptomyces coelicolor holo-ACP synthase (ACPS) and malonyl-CoA:ACP transacylase in vitro (10).…”

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confidence: 99%

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A Mammalian Type I Fatty Acid Synthase Acyl Carrier Protein Domain Does Not Sequester Acyl Chains

Płoskoń¹,

Arthur

Evans

et al. 2008

Journal of Biological Chemistry

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The synthases that produce fatty acids in mammals (FASs) are arranged as large multidomain polypeptides. The growing fatty acid chain is bound covalently during chain elongation and reduction to the acyl carrier protein (ACP) domain that is then able to access each catalytic site. In this work we report the highresolution nuclear magnetic resonance (NMR) solution structure of the isolated rat fatty acid synthase apoACP domain. Fatty acid biosynthesis in mammals is important not only for energy homeostasis and development but also as a potential target for the treatment of obesity (1) and cancer (2). Type I fatty acid synthases (FASs) 3 that catalyze the biosynthesis of fatty acids in mammals, utilize simple acyl units, bound to the phosphopantetheine arm of a holo acyl carrier protein (ACP) domain, for chain initiation and elongation. The recent elucidation of the low resolution structure of the mammalian FAS by x-ray crystallography (3) has provided key structural and mechanistic insights into this important enzyme. Although the resolution of the crystal is insufficient to discern the backbone and side chains, the electron density has permitted the authors to propose a model based on the structures of individual domains and homologous enzymes. The authors have proposed a "head to head" dimeric model that comprises a central core consisting of the enol-reductase, dehydratase (DH), and ketosynthase with the malonyl transferase and ketoreductase domains being located peripherally. Dimerization occurs through association of the KS domains. Notable absences in the crystal structure are the locations of the peripheral ACP and thioesterase domains, suggesting that the positions of the ACP and thioesterase domains are relatively mobile compared with the core of the FAS. In comparison, bacterial Type II FASs consist of discrete monofunctional proteins (4). Structural studies of the Type II FAS ACP components are particularly well developed and have revealed the structural basis of acyl chain binding and the phenomenon of conformational switching. The crystal structures of Escherichia coli FAS butyryl (5), hexanoyl-, heptanoyl-, and decanoyl-ACPs (6) and nuclear magnetic resonance (NMR) structures of spinach FAS decanoyl-and stearoyl-ACPs have been reported (7). These structures reveal that during fatty acid biosynthesis, fully saturated acyl chains are sequestered within a central cavity in the ACP formed through conformational changes in the protein. The fatty acid chain is sequestered within the hydrophobic core of the ACP perhaps to protect the thioester moiety from hydrolysis. Binding of the acyl chain also influences the dynamics of the ACPs. Spinach FAS holo-ACP exists in equilibrium between a folded and largely disordered form, however, upon acylation this equilibrium is shifted toward the folded form. At present the physiological role of switching of this, and other ACPs, is unknown (8, 9). It has been suggested that switching confers allosteric regulation of the ACP, whereby its interaction with other enzymes...

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Section: Methodsmentioning

confidence: 99%

Section: Structure Of Rat Fas Apoacp-mentioning

confidence: 99%

mentioning

confidence: 99%

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A Mammalian Type I Fatty Acid Synthase Acyl Carrier Protein Domain Does Not Sequester Acyl Chains

Płoskoń¹,

Arthur

Evans

et al. 2008

Journal of Biological Chemistry

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“…8). We prepared constructs expressing the individual ACP domain of SgcE, a general approach that has been successfully used to elucidate domain function for large multidomain PKS and FAS (39)(40)(41). Because nothing was known about the structural elements necessary for potential PPTase recognition of this type of ACP, five versions were prepared, ranging from a standard ACP size of 81 amino acids (ACP 81 ) to a long version (ACP 212 ) encompassing the majority of the region residing between the AT and KR.…”

Section: Si Text)mentioning

confidence: 99%

A phosphopantetheinylating polyketide synthase producing a linear polyene to initiate enediyne antitumor antibiotic biosynthesis

Zhang¹,

Lanen

et al. 2008

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

136

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The enediynes, unified by their unique molecular architecture and mode of action, represent some of the most potent anticancer drugs ever discovered. The biosynthesis of the enediyne core has been predicted to be initiated by a polyketide synthase (PKS) that is distinct from all known PKSs. Characterization of the enediyne PKS involved in C-1027 (SgcE) and neocarzinostatin (NcsE) biosynthesis has now revealed that (i) the PKSs contain a central acyl carrier protein domain and C-terminal phosphopantetheinyl transferase domain; (ii) the PKSs are functional in heterologous hosts, and coexpression with an enediyne thioesterase gene produces the first isolable compound, 1,3,5,7,9,11,13-pentadecaheptaene, in enediyne core biosynthesis; and (iii) the findings for SgcE and NcsE are likely shared among all nine-membered enediynes, thereby supporting a common mechanism to initiate enediyne biosynthesis.C-1027 ͉ neocarzinostatin ͉ phosphopantetheinyl transferase

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“…Conversely, mammalian ACP (malarial host) is an integral domain of one single multidomain, multifunctional fatty acid synthase (FAS) (type I pathway), each domain catalyzing a particular reaction. Interestingly, ACPs of type I and II pathway share a similar fold, the ACP molecule of type II pathway can be substituted with the ACP domain of type I pathway in some cases, and the latter is recognized as a substrate in vitro by key enzymes of type II pathway (9).…”

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confidence: 99%

Structural Insights into the Acyl Intermediates of the Plasmodium falciparum Fatty Acid Synthesis Pathway

Upadhyay

Misra

Srivastava

et al. 2009

Journal of Biological Chemistry

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Acyl carrier protein (ACP) plays a central role in fatty acid biosynthesis. However, the molecular machinery that mediates its function is not yet fully understood. Therefore, structural studies were carried out on the acyl-ACP intermediates of Plasmodium falciparum using NMR as a spectroscopic probe. Chemical shift perturbation studies put forth a new picture of the interaction of ACP molecule with the acyl chain, namely, the hydrophobic core can protect up to 12 carbon units, and additional carbons protrude out from the top of the hydrophobic cavity. The latter hypothesis stems from chemical shift changes observed in C ␣ and C ␤ of Ser-37 in tetradecanoyl-ACP. 13 C, 15 N-Double-filtered nuclear Overhauser effect (NOE) spectroscopy experiments further substantiate the concept; in octanoyl (C 8 )-and dodecanoyl (C 12 )-ACP, a long range NOE is observed within the phosphopantetheine arm, suggesting an arch-like conformation. This NOE is nearly invisible in tetradecanoyl (C 14 )-ACP, indicating a change in conformation of the prosthetic group. Furthermore, the present study provides insights into the molecular mechanism of ACP expansion, as revealed from a unique side chain-to-backbone hydrogen bond between two fairly conserved residues, Ile-55 HN and Glu-48 O. The backbone amide of Ile-55 HN reports a pK a value for the carboxylate, ϳ1.9 pH units higher than model compound value, suggesting strong electrostatic repulsion between helix II and helix III. Charge-charge repulsion between the helices in combination with thrust from inside due to acyl chain would energetically favor the separation of the two helices. Helix III has fewer structural restraints and, hence, undergoes major conformational change without altering the overall-fold of P. falciparum ACP.In the malarial parasite Plasmodium falciparum, fatty acid biosynthesis occurs by a pathway distinct from the host. A number of enzymes involved in the process viz. ␤-ketoacyl acyl carrier protein (ACP) 5 synthase III, ␤-hydroxy acyl-ACP hydratase, and enoyl-ACP reductase are targets for drug design (1, 2). An indispensable component, crucial for each step of the pathway, is a small acidic protein, the ACP. ACP plays a pivotal role in a range of biochemical processes, like fatty acid biosynthesis (3), polyketide synthesis (4, 5), oligosaccharides (6), biotin, and nonribosomal peptide synthesis (7,8). Thus, the knowledge of structural features, which dictate ACP function, could offer new avenues for inhibitor design to disable several pathways of the parasite in parallel.Acyl carrier protein differs structurally in the host and the parasite. It exists as an independent protein in type II fatty acid synthesis pathway, observed in P. falciparum, Escherichia coli, spinach, and most prokaryotes. In the type II pathway, fatty acids are synthesized by multiple enzymes catalyzing different reactions. Conversely, mammalian ACP (malarial host) is an integral domain of one single multidomain, multifunctional fatty acid synthase (FAS) (type I pathway), each domain catalyzin...

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The type I rat fatty acid synthase ACP shows structural homology and analogous biochemical properties to type II ACPs

Cited by 44 publications

References 49 publications

A Mammalian Type I Fatty Acid Synthase Acyl Carrier Protein Domain Does Not Sequester Acyl Chains

A Mammalian Type I Fatty Acid Synthase Acyl Carrier Protein Domain Does Not Sequester Acyl Chains

A phosphopantetheinylating polyketide synthase producing a linear polyene to initiate enediyne antitumor antibiotic biosynthesis

Structural Insights into the Acyl Intermediates of the Plasmodium falciparum Fatty Acid Synthesis Pathway

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