Agrobacterium tumefaciens VirB6 Domains Direct the Ordered Export of a DNA Substrate Through a Type IV Secretion System
| Autor: | Simon J. Jakubowski, Peter J. Christie, Eric Cascales, Vidhya Krishnamoorthy |
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| Přispěvatelé: | Laboratoire d'ingénierie des systèmes macromoléculaires (LISM), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Aix Marseille Université (AMU), Aix Marseille Université (AMU)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2004 |
| Předmět: |
Transfer DNA
Immunoprecipitation Protein subunit [SDV]Life Sciences [q-bio] Biology Article 03 medical and health sciences Structure-Activity Relationship Bacterial Proteins Structural Biology Secretion Molecular Biology ComputingMilieux_MISCELLANEOUS 030304 developmental biology DNA Primers Sequence Deletion 0303 health sciences Base Sequence 030306 microbiology C-terminus Biological Transport Periplasmic space Agrobacterium tumefaciens DNA biology.organism_classification Transmembrane protein Mutagenesis Insertional Biochemistry Biophysics |
| Zdroj: | Journal of Molecular Biology Journal of Molecular Biology, Elsevier, 2004, 341 (4), pp.961-977. ⟨10.1016/j.jmb.2004.06.052⟩ Journal of Molecular Biology, 2004, 341 (4), pp.961-977. ⟨10.1016/j.jmb.2004.06.052⟩ |
| ISSN: | 0022-2836 1089-8638 |
| Popis: | The Agrobacterium tumefaciens VirB/D4 type IV secretion system (T4SS) translocates DNA and protein substrates across the bacterial cell envelope. Six presumptive channel subunits of this T4SS (VirD4, VirB11, VirB6, VirB8, VirB2, and VirB9) form close contacts with the VirD2-T-strand transfer intermediate during export, as shown recently by a novel transfer DNA immunoprecipitation (TrIP) assay. Here, we characterize the contribution of the hydrophobic channel component VirB6 to substrate translocation. Results of reporter protein fusion and cysteine accessibility studies support a model for VirB6 as a polytopic membrane protein with a periplasmic N terminus, five transmembrane segments, and a cytoplasmic C terminus. TrIP studies aimed at characterizing the effects of VirB6 insertion and deletion mutations on substrate translocation identified several VirB6 functional domains: (i) a central region composed of a large periplasmic loop (P2) (residues 84 to 165) mediates the interaction of VirB6 with the exiting T-strand; (ii) a multi-membrane-spanning region carboxyl-terminal to loop P2 (residues 165 to 245) is required for substrate transfer from VirB6 to the bitopic membrane subunit VirB8; and (iii) the two terminal regions (residues 1 to 64 and 245 to 290) are required for substrate transfer to the periplasmic and outer membrane-associated VirB2 and VirB9 subunits. Our findings support a model whereby the periplasmic loop P2 comprises a portion of the secretion channel and distinct domains of VirB6 participate in channel subunit interactions required for substrate passage to the cell exterior. |
| Databáze: | OpenAIRE |
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