Document Detail


Fatty acid activation in cyanobacteria mediated by acyl-acyl carrier protein synthetase enables fatty acid recycling.
MedLine Citation:
PMID:  20061450     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In cyanobacteria fatty acids destined for lipid synthesis can be synthesized de novo, but also exogenous free fatty acids from the culture medium can be directly incorporated into lipids. Activation of exogenous fatty acids is likely required prior to their utilization. To identify the enzymatic activity responsible for activation we cloned candidate genes from Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942 and identified the encoded proteins as acyl-acyl carrier protein synthetases (Aas). The enzymes catalyze the ATP-dependent esterification of fatty acids to the thiol of acyl carrier protein. The two protein sequences are only distantly related to known prokaryotic Aas proteins but they display strong similarity to sequences that can be found in almost all organisms that perform oxygenic photosynthesis. To investigate the biological role of Aas activity in cyanobacteria, aas knockout mutants were generated in the background of Synechocystis sp. PCC 6803 and S. elongatus PCC 7942. The mutant strains showed two phenotypes characterized by the inability to utilize exogenous fatty acids and by the secretion of endogenous fatty acids into the culture medium. The analyses of extracellular and intracellular fatty acid profiles of aas mutant strains as well as labeling experiments indicated that the detected free fatty acids are released from membrane lipids. The data suggest a considerable turnover of lipid molecules and a role for Aas activity in recycling the released fatty acids. In this model, lipid degradation represents a third supply of fatty acids for lipid synthesis in cyanobacteria.
Authors:
Danuta Kaczmarzyk; Martin Fulda
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-01-08
Journal Detail:
Title:  Plant physiology     Volume:  152     ISSN:  1532-2548     ISO Abbreviation:  Plant Physiol.     Publication Date:  2010 Mar 
Date Detail:
Created Date:  2010-03-04     Completed Date:  2010-06-16     Revised Date:  2011-07-25    
Medline Journal Info:
Nlm Unique ID:  0401224     Medline TA:  Plant Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1598-610     Citation Subset:  IM    
Affiliation:
Department of Plant Biochemistry, Albrecht-von-Haller-Institute, Georg-August-University Goettingen, D-37077 Goettingen, Germany.
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MeSH Terms
Descriptor/Qualifier:
Bacterial Proteins / genetics,  metabolism
Carbon-Sulfur Ligases / genetics,  metabolism*
Cloning, Molecular
Coenzyme A Ligases / genetics,  metabolism
DNA, Bacterial / genetics
Fatty Acids / metabolism*
Gene Knockout Techniques
Phylogeny
Sequence Alignment
Substrate Specificity
Synechococcus / enzymology*,  genetics
Synechocystis / enzymology*,  genetics
Chemical
Reg. No./Substance:
0/Bacterial Proteins; 0/DNA, Bacterial; 0/Fatty Acids; EC 6.2.-/Carbon-Sulfur Ligases; EC 6.2.1.-/Coenzyme A Ligases; EC 6.2.1.20/long-chain-fatty-acid-(acyl-carrier-protein) ligase
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