| Characterization of the central carbon metabolism of Streptococcus pneumoniae by isotopologue profiling. | |
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MedLine Citation:
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PMID: 22167202 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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The metabolism of Streptococcus pneumoniae was studied by isotopologue profiling after bacterial cultivation in chemical 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 which were also essential for pneumococcal growth. Ala, Ser, Asp and Thr displayed high (13)C enrichments, while Phe, Tyr and Gly were only slightly labeled. The analysis of 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 PEP 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 phosphat pathway, and phosphoenol pyruvate. 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. |
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Authors:
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Tobias Haertel; Eva Eylert; Christian Schulz; Lothar Petruschka; Philipp Gierok; Stephanie Grubmueller; Michael Lalk; Wolfgang Eisenreich; Sven Hammerschmidt |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-12-13 |
Journal Detail:
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Title: The Journal of biological chemistry Volume: - ISSN: 1083-351X ISO Abbreviation: - Publication Date: 2011 Dec |
Date Detail:
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Created Date: 2011-12-14 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 2985121R Medline TA: J Biol Chem Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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Department Genetics of Microorganisms, Ernst Moritz Arndt Universitat Greifswald, Germany; |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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