Document Detail


Phosphatidic acid accumulation in the membranes of Escherichia coli mutants defective in CDP-diglyceride synthetase.
MedLine Citation:
PMID:  6243645     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
CTP-phosphatidic acid cytidylyltransferase (CDP-diglyceride synthetase) is a key enzyme in the biogenesis of membrane phospholipids in Escherichia coli. Using a modification of a previously described autoradiographic screening procedure (Raetz, C. R. H. (1975) Proc. Natl. Acad. Sci. U.S.A. 72, 2274-2278), we have isolated six mutant strains in which the specific activity of the synthetase is 1 to 10% that of the wild type, as judged by in vitro assays. The synthesis of dCDP-diglyceride, as well as CDP-diglyceride, is defective in these organisms. The mutations responsible for the enzyme defects (designated cds) all map in the same location near minute 4 on the chromosome. Although none of the mutants obtained are temperature-sensitive for growth, all of them exhibit significantly elevated levels of phosphatidic acid in vivo. The highest increase is observed in the mutant GL60, in which phosphatidic acid constitutes about 5% of the membrane lipid, in contrast to 0.2% in typical wild type strains. The accumulation of phosphatidic acid occurs primarily at the expense of phosphatidylglycerol and cardiolipin, but the total lipid-to-protein ratio of GL60 is nearly normal. In vivo labeling of GL60 with 32Pi suggests that the increased phosphatidic acid pool is the result of a partial metabolic block early in the phospholipid pathway, but that most of this expanded pool is nonetheless available for de novo synthesis.
Authors:
B R Ganong; J M Leonard; C R Raetz
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  255     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  1980 Feb 
Date Detail:
Created Date:  1980-04-23     Completed Date:  1980-04-23     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1623-9     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Cell Membrane / metabolism
Cytidine Diphosphate Diglycerides
Escherichia coli / genetics,  metabolism*
Genotype
Membrane Lipids / metabolism*
Mutation
Nucleotidyltransferases / genetics*
Phosphatidic Acids / metabolism*
Species Specificity
Transduction, Genetic
Chemical
Reg. No./Substance:
0/Cytidine Diphosphate Diglycerides; 0/Membrane Lipids; 0/Phosphatidic Acids; EC 2.7.7.-/Nucleotidyltransferases

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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