scholarly journals Characterization of Streptococcus pneumoniae enoyl-(acyl-carrier protein) reductase (FabK)

2003 ◽  
Vol 370 (3) ◽  
pp. 1055-1062 ◽  
Author(s):  
Hedia MARRAKCHI ◽  
Walter E. DeWOLF ◽  
Chad QUINN ◽  
Joshua WEST ◽  
Brian J. POLIZZI ◽  
...  

The enoyl-(acyl-carrier protein) (ACP) reductase catalyses the last step in each cycle of fatty acid elongation in the type II fatty acid synthase systems. An extensively characterized NADH-dependent reductase, FabI, is widely distributed in bacteria and plants, whereas the enoyl-ACP reductase, FabK, is a distinctly different member of this enzyme group discovered in Streptococcus pneumoniae. We were unable to delete the fabK gene from Strep. pneumoniae, suggesting that this is the only enoyl-ACP reductase in this organism. The FabK enzyme was purified and the biochemical properties of the reductase were examined. The visible absorption spectrum of the purified protein indicated the presence of a flavin cofactor that was identified as FMN by MS, and was present in a 1:1 molar ratio with protein. FabK specifically required NADH and the protein activity was stimulated by ammonium ions. FabK also exhibited NADH oxidase activity in the absence of substrate. Strep. pneumoniae belongs to the Bacillus/Lactobacillus/Streptococcus group that includes Staphylococcus aureus and Bacillus subtilis. These two organisms also contain FabK-related genes, suggesting that they may also express a FabK-like enoyl-ACP reductase. However, the genes did not complement a fabI(Ts) mutant and the purified flavoproteins were unable to reduce enoyl-ACP in vitro and did not exhibit NAD(P)H oxidase activity, indicating they were not enoyl-ACP reductases. The restricted occurrence of the FabK enoyl-ACP reductase may be related to the role of substrate-independent NADH oxidation in oxygen-dependent anaerobic energy metabolism.

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.


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.


PLoS ONE ◽  
2013 ◽  
Vol 8 (2) ◽  
pp. e57859 ◽  
Author(s):  
Uldaeliz Trujillo ◽  
Edwin Vázquez-Rosa ◽  
Delise Oyola-Robles ◽  
Loren J. Stagg ◽  
David A. Vassallo ◽  
...  

1988 ◽  
Vol 16 (3) ◽  
pp. 392-393 ◽  
Author(s):  
PHILIP S. SHELDON ◽  
RICHARD SAFFORD ◽  
ANTONI R. SLABAS ◽  
ROY G. O. KEKWICK

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

2000 ◽  
Vol 182 (2) ◽  
pp. 365-370 ◽  
Author(s):  
Keum-Hwa Choi ◽  
Richard J. Heath ◽  
Charles O. Rock

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.


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