genome of Clostridium kluyveri, a strict anaerobe with unique metabolic features

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 105; no. 6; pp. 2128 - 2133
• Main Authors: Seedorf, Henning, Fricke, W. Florian, Veith, Birgit, Brüggemann, Holger, Liesegang, Heiko, Strittmatter, Axel, Miethke, Marcus, Buckel, Wolfgang, Hinderberger, Julia, Li, Fuli, Hagemeier, Christoph, Thauer, Rudolf K, Gottschalk, Gerhard
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 12.02.2008; National Acad Sciences
• Subjects: acetaldehyde dehydrogenase; Acetates; Acetates - metabolism; Alcohol Dehydrogenase - metabolism; Aldehyde Oxidoreductases - metabolism; anaerobes; Bacteria; Biological Sciences; Butyrates; Clostridium; Clostridium kluyveri; Clostridium kluyveri - enzymology; Clostridium kluyveri - genetics; Clostridium kluyveri - metabolism; Dehydrogenase; Dehydrogenases; energy; Energy conservation; Energy sources; Enzymes; Ethanol; Ethanol - metabolism; Fermentation; Ferredoxins; genes; Genome, Bacterial; Genomes; Genomics; Glycerol - metabolism; Growth conditions; hexanoic acid; hydrogen; Molecular Sequence Data; nucleotide sequences; Peptides; Phenols - metabolism; proteins; Siderophores; Succinic Acid - metabolism; Thiazoles - metabolism
• ISSN: 0027-8424; 1091-6490; 1091-6490
• DOI: 10.1073/pnas.0711093105

Clostridium kluyveri is unique among the clostridia; it grows anaerobically on ethanol and acetate as sole energy sources. Fermentation products are butyrate, caproate, and H₂. We report here the genome sequence of C. kluyveri, which revealed new insights into the metabolic capabilities of this well studied organism. A membrane-bound energy-converting NADH:ferredoxin oxidoreductase (RnfCDGEAB) and a cytoplasmic butyryl-CoA dehydrogenase complex (Bcd/EtfAB) coupling the reduction of crotonyl-CoA to butyryl-CoA with the reduction of ferredoxin represent a new energy-conserving module in anaerobes. The genes for NAD-dependent ethanol dehydrogenase and NAD(P)-dependent acetaldehyde dehydrogenase are located next to genes for microcompartment proteins, suggesting that the two enzymes, which are isolated together in a macromolecular complex, form a carboxysome-like structure. Unique for a strict anaerobe, C. kluyveri harbors three sets of genes predicted to encode for polyketide/nonribosomal peptide synthetase hybrides and one set for a nonribosomal peptide synthetase. The latter is predicted to catalyze the synthesis of a new siderophore, which is formed under iron-deficient growth conditions.