Type III protein translocase: HrcN is a peripheral ATPase that is activated by oligomerization
| Autor: | Pozidis, C., Chalkiadaki, A., Gomez-Serrano, A., Stahlberg, H., Brown, I., Tampakaki, A. P., Lustig, A., Sianidis, G., Politou, A. S., Engel, A., Panopoulos, N. J., Mansfield, J., Pugsley, A. P., Karamanou, S., Economou, A. |
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| Jazyk: | angličtina |
| Rok vydání: | 2003 |
| Předmět: |
Protein Folding
Protein Conformation Molecular Sequence Data Bacterial Proteins/*chemistry Protein Structure Secondary Amino Acid Sequence Pseudomonas/*enzymology Ions Chromatography Membrane Transport Proteins/*chemistry/*physiology Water/metabolism Dose-Response Relationship Drug Circular Dichroism Hydrolysis Temperature Hydrogen-Ion Concentration Plasmids/metabolism Cross-Linking Reagents/pharmacology Protein Structure Tertiary Kinetics Microscopy Electron Protein Transport Detergents/pharmacology Cell Membrane/enzymology/metabolism Escherichia coli/metabolism Adenosine Triphosphatases/*chemistry/*physiology Subcellular Fractions |
| Popis: | Type III protein secretion (TTS) is catalyzed by translocases that span both membranes of Gram-negative bacteria. A hydrophilic TTS component homologous to F1/V1-ATPases is ubiquitous and essential for secretion. We show that hrcN encodes the putative TTS ATPase of Pseudomonas syringae pathovar phaseolicola and that HrcN is a peripheral protein that assembles in clusters at the membrane. A decahistidinyl HrcN derivative was overexpressed in Escherichia coli and purified to homogeneity in a folded state. Hydrodynamic analysis, cross-linking, and electron microscopy revealed four distinct HrcN forms: I, 48 kDa (monomer); II, approximately 300 kDa (putative hexamer); III, 575 kDa (dodecamer); and IV, approximately 3.5 MDa. Form III is the predominant form of HrcN at the membrane, and its ATPase activity is dramatically stimulated (>700-fold) over the basal activity of Form I. We propose that TTS ATPases catalyze protein translocation as activated homo-oligomers at the plasma membrane. J Biol Chem |
| Databáze: | OpenAIRE |
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