Document Detail


An NMR and enzyme study of the carbon metabolism of Neisseria meningitidis.
MedLine Citation:
PMID:  11390678     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The pathogenic neisseriae are fastidious bacteria that are only able to grow on a restricted range of carbon sources. The genome sequence of Neisseria meningitidis strain MC58 predicts the presence of a complete citric acid cycle (CAC), but there have been no detailed biochemical studies of carbon metabolism in this important pathogen. In this study, both NMR and conventional enzyme assays were used to investigate the central metabolic pathways of a serogroup B strain (K454). (13)C-NMR labelling patterns of amino acids from hydrolysed cell proteins after growth with either 2- or 3-[(13)C]pyruvate were consistent with the operation of a complete oxidative CAC. Enzyme assays showed that cell-free extracts contained all the CAC enzymes predicted from the genome sequence, including a membrane-bound malate:quinone oxidoreductase which is present in place of the conventional NAD-linked cytoplasmic malate dehydrogenase. (1)H-NMR studies showed that growth on glucose, lactate and, especially, pyruvate, resulted in the excretion of significant amounts of acetate into the culture supernatant. This occurred via the phosphotransacetylase (PTA)-acetate kinase (ACK) pathway. Extremely high specific activities of PTA (7-14 micromol min(-1) mg(-1)) were detected in cell-free extracts, although ACK activities were much lower (46-298 nmol min(-1) mg(-1)). Expression of PTA and ACK activities was not co-ordinately regulated during growth on combinations of carbon sources. This may be related to the presence of two ackA paralogues in N. meningitidis which are, unusually, unlinked to the pta gene.
Authors:
M P Leighton; D J Kelly; M P Williamson; J G Shaw
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Microbiology (Reading, England)     Volume:  147     ISSN:  1350-0872     ISO Abbreviation:  Microbiology (Reading, Engl.)     Publication Date:  2001 Jun 
Date Detail:
Created Date:  2001-06-06     Completed Date:  2001-11-01     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9430468     Medline TA:  Microbiology     Country:  England    
Other Details:
Languages:  eng     Pagination:  1473-82     Citation Subset:  IM    
Affiliation:
Division of Molecular and Genetic Medicine, University of Sheffield Medical School, Sheffield S10 2RX, UK.
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MeSH Terms
Descriptor/Qualifier:
Acetate Kinase / metabolism
Carbon / metabolism*
Citric Acid Cycle*
Culture Media
Glucose / metabolism
Lactic Acid / metabolism
Magnetic Resonance Spectroscopy
Neisseria meningitidis / enzymology,  growth & development,  metabolism*
Phosphate Acetyltransferase / metabolism
Pyruvic Acid / metabolism
Chemical
Reg. No./Substance:
0/Culture Media; 127-17-3/Pyruvic Acid; 50-21-5/Lactic Acid; 50-99-7/Glucose; 7440-44-0/Carbon; EC 2.3.1.8/Phosphate Acetyltransferase; EC 2.7.2.1/Acetate Kinase

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


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