Document Detail

Characterization of central carbon metabolism of Streptococcus pneumoniae by isotopologue profiling.
MedLine Citation:
PMID:  22167202     Owner:  NLM     Status:  MEDLINE    
The metabolism of Streptococcus pneumoniae was studied by isotopologue profiling after bacterial cultivation in chemically defined medium supplemented with [U-(13)C(6)]- or [1,2-(13)C(2)]glucose. GC/MS analysis of protein-derived amino acids showed lack of (13)C label in amino acids that were also essential for pneumococcal growth. Ala, Ser, Asp, and Thr displayed high (13)C enrichments, whereas Phe, Tyr, and Gly were only slightly labeled. The analysis of the labeling patterns showed formation of triose phosphate and pyruvate via the Embden-Meyerhof-Parnas pathway. The labeling patterns of Asp and Thr suggested formation of oxaloacetate exclusively via the phosphoenolpyruvate carboxylase reaction. Apparently, α-ketoglutarate was generated from unlabeled glutamate via the aspartate transaminase reaction. A fraction of Phe and Tyr obtained label via the chorismate route from erythrose 4-phosphate, generated via the pentose phosphate pathway, and phosphoenolpyruvate. Strikingly, the data revealed no significant flux from phosphoglycerate to Ser and Gly but showed formation of Ser via the reverse reaction, namely by hydroxymethylation of Gly. The essential Gly was acquired from the medium, and the biosynthesis pathway was confirmed in experiments using [U-(13)C(2)]glycine as a tracer. The hydroxymethyl group in Ser originated from formate, which was generated by the pyruvate formate-lyase. Highly similar isotopologue profiles were observed in corresponding experiments with pneumococcal mutants deficient in PavA, CodY, and glucose-6-phosphate dehydrogenase pointing to the robustness of the core metabolic network used by these facultative pathogenic bacteria. In conclusion, this study demonstrates the dual utilization of carbohydrates and amino acids under in vitro conditions and identifies the unconventional de novo biosynthesis of serine by pneumococci.
Tobias Härtel; Eva Eylert; Christian Schulz; Lothar Petruschka; Philipp Gierok; Stephanie Grubmüller; Michael Lalk; Wolfgang Eisenreich; Sven Hammerschmidt
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2011-12-13
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  287     ISSN:  1083-351X     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2012 Feb 
Date Detail:
Created Date:  2012-02-06     Completed Date:  2012-03-25     Revised Date:  2013-06-27    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  4260-74     Citation Subset:  IM    
Department of Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, Ernst Moritz Arndt Universität Greifswald, Friedrich-Ludwig-Jahn-Strasse 15a, D-17487 Greifswald, Germany.
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MeSH Terms
Amino Acids / metabolism*
Bacterial Proteins / genetics,  metabolism
Carbon / metabolism*
Carbon Isotopes / pharmacology
Glycolysis / physiology*
Streptococcus pneumoniae / genetics,  metabolism*
Reg. No./Substance:
0/Amino Acids; 0/Bacterial Proteins; 0/Carbon Isotopes; 0/PavA protein, Streptococcus pneumoniae; 7440-44-0/Carbon

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