| Autor: |
Pozidis C; Institute of Molecular Biology and Biotechnology, FORTH and Department of Biology, University of Crete, P.O. Box 1527, GR-711 10 Iraklio, Crete, Greece., Chalkiadaki A, Gomez-Serrano A, Stahlberg H, Brown I, Tampakaki AP, Lustig A, Sianidis G, Politou AS, Engel A, Panopoulos NJ, Mansfield J, Pugsley AP, Karamanou S, Economou A |
| Jazyk: |
angličtina |
| Zdroj: |
The Journal of biological chemistry [J Biol Chem] 2003 Jul 11; Vol. 278 (28), pp. 25816-24. Date of Electronic Publication: 2003 May 06. |
| DOI: |
10.1074/jbc.M301903200 |
| Abstrakt: |
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. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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