AMP-Forming Acetyl Coenzyme A Synthetase in the Outermost Membrane of the Hyperthermophilic Crenarchaeon Ignicoccus hospitalis
| Autor: | Volker Müller, Harald Huber, Ulf Küper, Florian Mayer, Carolin Meyer, Stefanie Daxer, Reinhard Rachel |
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| Rok vydání: | 2012 |
| Předmět: |
Ignicoccus
Archaeal Proteins Acetate-CoA Ligase Models Biological Microbiology Oxidoreductase Electrophoresis Gel Two-Dimensional Molecular Biology chemistry.chemical_classification Microscopy biology ATP synthase Molecular mass Desulfurococcaceae Membrane Proteins Articles biology.organism_classification Adenosine Monophosphate Molecular Weight Membrane Enzyme chemistry Biochemistry Membrane protein Spectrometry Mass Matrix-Assisted Laser Desorption-Ionization biology.protein Protein Multimerization |
| Zdroj: | Journal of Bacteriology. 194:1572-1581 |
| ISSN: | 1098-5530 0021-9193 |
| DOI: | 10.1128/jb.06130-11 |
| Popis: | Ignicoccus hospitalis , a hyperthermophilic, chemolithoautotrophic crenarchaeon was found to possess a new CO 2 fixation pathway, the dicarboxylate/4-hydroxybutyrate cycle. The primary acceptor molecule for this pathway is acetyl coenzyme A (acetyl-CoA), which is regenerated in the cycle via the characteristic intermediate 4-hydroxybutyrate. In the presence of acetate, acetyl-CoA can alternatively be formed in a one-step mechanism via an AMP-forming acetyl-CoA synthetase (ACS). This enzyme was identified after membrane preparation by two-dimensional native PAGE/SDS-PAGE, followed by matrix-assisted laser desorption ionization–time of flight tandem mass spectrometry and N-terminal sequencing. The ACS of I. hospitalis exhibits a molecular mass of ∼690 kDa with a monomeric molecular mass of 77 kDa. Activity tests on isolated membranes and bioinformatic analyses indicated that the ACS is a constitutive membrane-associated (but not an integral) protein complex. Unexpectedly, immunolabeling on cells of I. hospitalis and other described Ignicoccus species revealed that the ACS is localized at the outermost membrane. This perfectly coincides with recent results that the ATP synthase and the H 2 :sulfur oxidoreductase complexes are also located in the outermost membrane of I. hospitalis . These results imply that the intermembrane compartment of I. hospitalis is not only the site of ATP synthesis but may also be involved in the primary steps of CO 2 fixation. |
| Databáze: | OpenAIRE |
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