TY - JOUR
T1 - Lactococcus lactis fabH, encoding β-ketoacyl-acyl carrier protein synthase, can be functionally replaced by the plasmodium falciparum congener
AU - Du, Yu
AU - Gisselberg, Jolyn E.
AU - Johnson, Jacob D.
AU - Lee, Patricia J.
AU - Prigge, Sean T.
AU - Bachmann, Brian O.
PY - 2010/6
Y1 - 2010/6
N2 - Plasmodium falciparum, in addition to scavenging essential fatty acids from its intra- and intercellular environments, possesses a functional complement of type II fatty acid synthase (FAS) enzymes targeted to the apicoplast organelle. Recent evidence suggests that products of the plasmodial FAS II system may be critical for the parasite's liver-to-blood cycle transition, and it has been speculated that endogenously generated fatty acids may be precursors for essential cofactors, such as lipoate, in the apicoplast. β-Ketoacyl-acyl carrier protein (ACP) synthase III (pfKASIII or FabH) is one of the key enzymes in the initiating steps of the FAS II pathway, possessing two functions in P. falciparum: the decarboxylase thio-Claisen condensation of malonylACP and various acyl coenzymes A (acyl-CoAs; KAS activity) and the acetyl-CoA:ACP transacylase reaction (ACAT). Here, we report the generation and characterization of a hybrid Lactococcus lactis strain that translates pfKASIII instead of L. lactis fabH to initiate fatty acid biosynthesis. The L. lactis expression vector pMG36e was modified for the efficient overexpression of the plasmodial gene in L. lactis. Transcriptional analysis indicated high-efficiency overexpression, and biochemical KAS and ACAT assays confirm these activities in cell extracts. Phenotypically, the L. lactis strain expressing pfKASIII has a growth rate and fatty acid profiles that are comparable to those of the strain complemented with its endogenous gene, suggesting that pfKASIII can use L. lactis ACP as substrate and perform near-normal function in L. lactis cells. This strain may have potential application as a bacterial model for pfKASIII inhibitor prescreening.
AB - Plasmodium falciparum, in addition to scavenging essential fatty acids from its intra- and intercellular environments, possesses a functional complement of type II fatty acid synthase (FAS) enzymes targeted to the apicoplast organelle. Recent evidence suggests that products of the plasmodial FAS II system may be critical for the parasite's liver-to-blood cycle transition, and it has been speculated that endogenously generated fatty acids may be precursors for essential cofactors, such as lipoate, in the apicoplast. β-Ketoacyl-acyl carrier protein (ACP) synthase III (pfKASIII or FabH) is one of the key enzymes in the initiating steps of the FAS II pathway, possessing two functions in P. falciparum: the decarboxylase thio-Claisen condensation of malonylACP and various acyl coenzymes A (acyl-CoAs; KAS activity) and the acetyl-CoA:ACP transacylase reaction (ACAT). Here, we report the generation and characterization of a hybrid Lactococcus lactis strain that translates pfKASIII instead of L. lactis fabH to initiate fatty acid biosynthesis. The L. lactis expression vector pMG36e was modified for the efficient overexpression of the plasmodial gene in L. lactis. Transcriptional analysis indicated high-efficiency overexpression, and biochemical KAS and ACAT assays confirm these activities in cell extracts. Phenotypically, the L. lactis strain expressing pfKASIII has a growth rate and fatty acid profiles that are comparable to those of the strain complemented with its endogenous gene, suggesting that pfKASIII can use L. lactis ACP as substrate and perform near-normal function in L. lactis cells. This strain may have potential application as a bacterial model for pfKASIII inhibitor prescreening.
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U2 - 10.1128/AEM.00170-10
DO - 10.1128/AEM.00170-10
M3 - Article
C2 - 20418430
AN - SCOPUS:77953635532
SN - 0099-2240
VL - 76
SP - 3959
EP - 3966
JO - Applied and environmental microbiology
JF - Applied and environmental microbiology
IS - 12
ER -