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Structure–Function Analysis of the C-Terminal Domain of the Type VI Secretion TssB Tail Sheath Subunit
- Source :
- Journal of Molecular Biology, Journal of Molecular Biology, 2018, 430 (3), pp.297-309. ⟨10.1016/j.jmb.2017.11.015⟩, Journal of Molecular Biology, Elsevier, 2018, 430 (3), pp.297-309. ⟨10.1016/j.jmb.2017.11.015⟩
- Publication Year :
- 2018
- Publisher :
- HAL CCSD, 2018.
-
Abstract
- International audience; The type VI secretion system (T6SS) is a specialized macromolecular complex dedicated to the delivery of protein effectors into both eukaryotic and bacterial cells. The general mechanism of action of the T6SS is similar to the injection of DNA by contractile bacteriophages. The cytoplasmic portion of the T6SS is evolutionarily, structurally and functionally related to the phage tail complex. It is composed of an inner tube made of stacked Hcp hexameric rings, engulfed within a sheath and built on a baseplate. This sheath undergoes cycles of extension and contraction, and the current model proposes that the sheath contraction propels the inner tube toward the target cell for effector delivery. The sheath comprises two subunits: TssB and TssC that polymerize under an extended conformation. Here, we show that isolated TssB forms trimers, and we report the crystal structure of a C-terminal fragment of TssB. This fragment comprises a long helix followed by a helical hairpin that presents surface-exposed charged residues. Site-directed mutagenesis coupled to functional assay further showed that these charges are required for proper assembly of the sheath. Positioning of these residues in the extended T6SS sheath structure suggests that they may mediate contacts with the baseplate.
- Subjects :
- 0301 basic medicine
Models, Molecular
Protein Conformation
Protein subunit
[SDV]Life Sciences [q-bio]
030106 microbiology
Protein domain
Crystallography, X-Ray
03 medical and health sciences
chemistry.chemical_compound
Protein structure
Protein Domains
Structural Biology
Type VI Secretion Systems/*chemistry
Escherichia coli
sheath
[SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology
[SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM]
Molecular Biology
ComputingMilieux_MISCELLANEOUS
Type VI secretion system
Escherichia coli Proteins/*chemistry
contractile injection system
[SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM]
Effector
C-terminus
Escherichia coli Proteins
X-ray
protein secretion
[SDV.BBM.BM]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology
Escherichia coli/*chemistry
Type VI Secretion Systems
[SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology
[SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biomolecules [q-bio.BM]
[SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics
[SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biomolecules [q-bio.BM]
030104 developmental biology
chemistry
Cytoplasm
Biophysics
structure
Protein Multimerization
DNA
Subjects
Details
- Language :
- English
- ISSN :
- 00222836 and 10898638
- Database :
- OpenAIRE
- Journal :
- Journal of Molecular Biology, Journal of Molecular Biology, 2018, 430 (3), pp.297-309. ⟨10.1016/j.jmb.2017.11.015⟩, Journal of Molecular Biology, Elsevier, 2018, 430 (3), pp.297-309. ⟨10.1016/j.jmb.2017.11.015⟩
- Accession number :
- edsair.doi.dedup.....2e581b7f1c9c27388df743e3261240c5