Several systems, including contractile tail bacteriophages, the type VI secretion system and R-type pyocins, use a multiprotein tubular apparatus to attach to and penetrate host cell membranes. This macromolecular machine resembles a stretched, coiled spring (or sheath) wound around a rigid tube with a spike-shaped protein at its tip. A baseplate structure, which is arguably the most complex part of this assembly, relays the contraction signal to the sheath. Here we present the atomic structure of the approximately 6-megadalton bacteriophage T4 baseplate in its pre- and post-host attachment states and explain the events that lead to sheath contraction in atomic detail. We establish the identity and function of a minimal set of components that is conserved in all contractile injection systems and show that the triggering mechanism is universally conserved.
This is a preview of subscription content, access via your institution
Open Access articles citing this article.
Genome wide analysis revealed conserved domains involved in the effector discrimination of bacterial type VI secretion system
Communications Biology Open Access 24 November 2023
Nature Communications Open Access 08 July 2023
Nature Communications Open Access 30 May 2023
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Rent or buy this article
Prices vary by article type
Prices may be subject to local taxes which are calculated during checkout
Electron Microscopy Data Bank
NCBI Reference Sequence
Protein Data Bank
Cryo-EM maps have been deposited in the Electron Microscopy Data Bank under the following accession numbers: EMD-3374 and EMD-3396 for the pre-attachment and post-attachment baseplate, respectively, and EMD-3397, EMD-3392, EMD-3393, EMD-3394 and EMD-3395 for the locally masked reconstructions of the pre-attachment baseplate for the tail tube, inner, intermediate, upper and lower peripheral baseplate regions, respectively. Atomic coordinates have been deposited in the Protein Data Bank under the following accession numbers: 5IV5 and 5IV7 for the pre-attachment and post-attachment baseplate, respectively, and 4HRZ for the crystal structure of T4 gp25. The vector with the TEV-cleavable His–SlyD expression tag derived from pET-23d(+) (Novagen) has been deposited to the NCBI database under the accession number KU314761.
Leiman, P. G. & Shneider, M. M. Contractile tail machines of bacteriophages. Adv. Exp. Med. Biol. 726, 93–114 (2012)
Hu, B., Margolin, W., Molineux, I. J. & Liu, J. Structural remodeling of bacteriophage T4 and host membranes during infection initiation. Proc. Natl Acad. Sci. USA 112, E4919–E4928 (2015)
Kostyuchenko, V. A. et al. The tail structure of bacteriophage T4 and its mechanism of contraction. Nature Struct. Mol. Biol . 12, 810–813 (2005)
Leiman, P. G., Chipman, P. R., Kostyuchenko, V. A., Mesyanzhinov, V. V. & Rossmann, M. G. Three-dimensional rearrangement of proteins in the tail of bacteriophage T4 on infection of its host. Cell 118, 419–429 (2004)
Kanamaru, S. et al. Structure of the cell-puncturing device of bacteriophage T4. Nature 415, 553–557 (2002)
Browning, C., Shneider, M. M., Bowman, V. D., Schwarzer, D. & Leiman, P. G. Phage pierces the host cell membrane with the iron-loaded spike. Structure 20, 326–339 (2012)
Leiman, P. G. et al. Type VI secretion apparatus and phage tail-associated protein complexes share a common evolutionary origin. Proc. Natl Acad. Sci. USA 106, 4154–4159 (2009)
Basler, M. Type VI secretion system: secretion by a contractile nanomachine. Phil. Trans. R. Soc. Lond. B 370, 20150021 (2015)
Shneider, M. M. et al. PAAR-repeat proteins sharpen and diversify the type VI secretion system spike. Nature 500, 350–353 (2013)
Basler, M., Pilhofer, M., Henderson, G. P., Jensen, G. J. & Mekalanos, J. J. Type VI secretion requires a dynamic contractile phage tail-like structure. Nature 483, 182–186 (2012)
Mougous, J. D. et al. A virulence locus of Pseudomonas aeruginosa encodes a protein secretion apparatus. Science 312, 1526–1530 (2006)
Shikuma, N. J. et al. Marine tubeworm metamorphosis induced by arrays of bacterial phage tail-like structures. Science 343, 529–533 (2014)
Nakayama, K. et al. The R-type pyocin of Pseudomonas aeruginosa is related to P2 phage, and the F-type is related to lambda phage. Mol. Microbiol. 38, 213–231 (2000)
Ge, P. et al. Atomic structures of a bactericidal contractile nanotube in its pre- and postcontraction states. Nature Struct. Mol. Biol . 22, 377–382 (2015)
Heymann, J. B. et al. Three-dimensional structure of the toxin-delivery particle antifeeding prophage of Serratia entomophila. J. Biol. Chem. 288, 25276–25284 (2013)
Yang, G., Dowling, A. J. & Gerike, U. ffrench-Constant, R. H. & Waterfield, N. R. Photorhabdus virulence cassettes confer injectable insecticidal activity against the wax moth. J. Bacteriol. 188, 2254–2261 (2006)
Yamamoto, T. Presence of rhapidosomes in various species of bacteria and their morphological characteristics. J. Bacteriol. 94, 1746–1756 (1967)
Bönemann, G., Pietrosiuk, A. & Mogk, A. Tubules and donuts: a type VI secretion story. Mol. Microbiol. 76, 815–821 (2010)
Leiman, P. G. et al. Morphogenesis of the T4 tail and tail fibers. Virol. J. 7, 355 (2010)
Kikuchi, Y. & King, J. Genetic control of bacteriophage T4 baseplate morphogenesis. I. Sequential assembly of the major precursor, in vivo and in vitro. J. Mol. Biol. 99, 645–672 (1975)
Kikuchi, Y. & King, J. Genetic control of bacteriophage T4 baseplate morphogenesis. II. Mutants unable to form the central part of the baseplate. J. Mol. Biol. 99, 673–694 (1975)
Kikuchi, Y. & King, J. Genetic control of bacteriophage T4 baseplate morphogenesis. III. Formation of the central plug and overall assembly pathway. J. Mol. Biol. 99, 695–716 (1975)
Coombs, D. H. & Arisaka, F. in Molecular Biology of Bacteriophage T4 (ed. Karam, J. D. ) 259–281 (American Society for Microbiology, 1994)
Kikuchi, Y. & King, J. Assembly of the tail of bacteriophage T4. J. Supramol. Struct. 3, 24–38 (1975)
De Rosier, D. J. & Klug, A. Reconstruction of three dimensional structures from electron micrographs. Nature 217, 130–134 (1968)
Kostyuchenko, V. A. et al. Three-dimensional structure of bacteriophage T4 baseplate. Nature Struct. Biol. 10, 688–693 (2003)
Aksyuk, A. A. et al. The tail sheath structure of bacteriophage T4: a molecular machine for infecting bacteria. EMBO J. 28, 821–829 (2009)
Amos, L. A. & Klug, A. Three-dimensional image reconstructions of the contractile tail of T4 bacteriophage. J. Mol. Biol. 99, 51–64 (1975)
Effantin, G. et al. Cryo-electron microscopy three-dimensional structure of the jumbo phage PhiRSL1 infecting the phytopathogen Ralstonia solanacearum. Structure 21, 298–305 (2013)
Liu, J., Chen, C. Y., Shiomi, D., Niki, H. & Margolin, W. Visualization of bacteriophage P1 infection by cryo-electron tomography of tiny Escherichia coli. Virology 417, 304–311 (2011)
Kudryashev, M. et al. Structure of the type VI secretion system contractile sheath. Cell 160, 952–962 (2015)
Clemens, D. L., Ge, P., Lee, B. Y., Horwitz, M. A. & Zhou, Z. H. Atomic structure of T6SS reveals interlaced array essential to function. Cell 160, 940–951 (2015)
Crowther, R. A., Lenk, E. V., Kikuchi, Y. & King, J. Molecular reorganization in the hexagon to star transition of the baseplate of bacteriophage T4. J. Mol. Biol. 116, 489–523 (1977)
Amunts, A., Brown, A., Toots, J., Scheres, S. H. & Ramakrishnan, V. Ribosome. The structure of the human mitochondrial ribosome. Science 348, 95–98 (2015)
Yan, C. et al. Structure of a yeast spliceosome at 3.6-angstrom resolution. Science 349, 1182–1191 (2015)
Aksyuk, A. A., Leiman, P. G., Shneider, M. M., Mesyanzhinov, V. V. & Rossmann, M. G. The structure of gene product 6 of bacteriophage T4, the hinge-pin of the baseplate. Structure 17, 800–808 (2009)
Maxwell, K. L. et al. Structural and functional studies of gpX of Escherichia coli phage P2 reveal a widespread role for LysM domains in the baseplates of contractile-tailed phages. J. Bacteriol. 195, 5461–5468 (2013); correction 196, 2122 (2014)
Lossi, N. S., Dajani, R., Freemont, P. & Filloux, A. Structure-function analysis of HsiF, a gp25-like component of the type VI secretion system, in Pseudomonas aeruginosa. Microbiology 157, 3292–3305 (2011)
Veesler, D. & Johnson, J. E. Virus maturation. Annu. Rev. Biophys. 41, 473–496 (2012)
Silverman, J. M. et al. Haemolysin coregulated protein is an exported receptor and chaperone of type VI secretion substrates. Mol. Cell 51, 584–593 (2013)
Kostyuchenko, V. A. et al. The structure of bacteriophage T4 gene product 9: the trigger for tail contraction. Structure 7, 1213–1222 (1999)
Zhao, L., Takeda, S., Leiman, P. G. & Arisaka, F. Stoichiometry and inter-subunit interaction of the wedge initiation complex, gp10-gp11, of bacteriophage T4. Biochim. Biophys. Acta 1479, 286–292 (2000)
Thomassen, E. et al. The structure of the receptor-binding domain of the bacteriophage T4 short tail fibre reveals a knitted trimeric metal-binding fold. J. Mol. Biol. 331, 361–373 (2003)
van Raaij, M. J., Schoehn, G., Burda, M. R. & Miller, S. Crystal structure of a heat and protease-stable part of the bacteriophage T4 short tail fibre. J. Mol. Biol. 314, 1137–1146 (2001)
Söding, J. Protein homology detection by HMM-HMM comparison. Bioinformatics 21, 951–960 (2005)
Remmert, M., Biegert, A., Hauser, A. & Soding, J. HHblits: lightning-fast iterative protein sequence searching by HMM-HMM alignment. Nature Methods 9, 173–175 (2012)
Zoued, A. et al. TssK is a trimeric cytoplasmic protein interacting with components of both phage-like and membrane anchoring complexes of the type VI secretion system. J. Biol. Chem. 288, 27031–27041 (2013)
Yap, M. L. et al. Role of bacteriophage T4 baseplate in regulating assembly and infection. Proc. Natl Acad. Sci. USA 113, 2654–2659 (2016)
Pettersen, E. F. et al. UCSF Chimera—a visualization system for exploratory research and analysis. J. Comput. Chem. 25, 1605–1612 (2004)
Fokine, A. et al. The molecular architecture of the bacteriophage T4 neck. J. Mol. Biol. 425, 1731–1744 (2013)
Doermann, A. H. Lysis and lysis inhibition with Escherichia coli bacteriophage. J. Bacteriol. 55, 257–276 (1948)
Li, X. et al. Electron counting and beam-induced motion correction enable near-atomic-resolution single-particle cryo-EM. Nature Methods 10, 584–590 (2013)
Scherer, S. et al. 2dx_automator: implementation of a semiautomatic high-throughput high-resolution cryo-electron crystallography pipeline. J. Struct. Biol. 186, 302–307 (2014)
Rohou, A. & Grigorieff, N. CTFFIND4: fast and accurate defocus estimation from electron micrographs. J. Struct. Biol. 192, 216–221 (2015)
Tang, G. et al. EMAN2: an extensible image processing suite for electron microscopy. J. Struct. Biol. 157, 38–46 (2007)
Scheres, S. H. RELION: implementation of a Bayesian approach to cryo-EM structure determination. J. Struct. Biol. 180, 519–530 (2012)
Rosenthal, P. B. & Henderson, R. Optimal determination of particle orientation, absolute hand, and contrast loss in single-particle electron cryomicroscopy. J. Mol. Biol. 333, 721–745 (2003)
Pintilie, G. D., Zhang, J., Goddard, T. D., Chiu, W. & Gossard, D. C. Quantitative analysis of cryo-EM density map segmentation by watershed and scale-space filtering, and fitting of structures by alignment to regions. J. Struct. Biol. 170, 427–438 (2010)
Leiman, P. G. et al. Structure of bacteriophage T4 gene product 11, the interface between the baseplate and short tail fibers. J. Mol. Biol. 301, 975–985 (2000)
Leiman, P. G., Shneider, M. M., Mesyanzhinov, V. V. & Rossmann, M. G. Evolution of bacteriophage tails: Structure of T4 gene product 10. J. Mol. Biol. 358, 912–921 (2006)
Leiman, P. G. et al. Structure and location of gene product 8 in the bacteriophage T4 baseplate. J. Mol. Biol. 328, 821–833 (2003)
Emsley, P. & Cowtan, K. Coot: model-building tools for molecular graphics. Acta Crystallogr. D 60, 2126–2132 (2004)
Söding, J., Biegert, A. & Lupas, A. N. The HHpred interactive server for protein homology detection and structure prediction. Nucleic Acids Res. 33, W244–W248 (2005)
Kelley, L. A., Mezulis, S., Yates, C. M., Wass, M. N. & Sternberg, M. J. The Phyre2 web portal for protein modeling, prediction and analysis. Nature Protocols 10, 845–858 (2015)
Eswar, N. et al. Comparative protein structure modeling using MODELLER. Curr. Protoc. Protein Sci. 50, 2.9:2.9.1–2.9.31 (2007)
Perrakis, A., Morris, R. & Lamzin, V. S. Automated protein model building combined with iterative structure refinement. Nature Struct. Biol. 6, 458–463 (1999)
Afonine, P. V., Headd, J. J., Terwilliger, T. C. & Adams, P. D. New tool: phenix.real_space_refine. Comput. Crystallogr. Newslett . 4, 43–44 (2013)
Brown, A. et al. Tools for macromolecular model building and refinement into electron cryo-microscopy reconstructions. Acta Crystallogr. D 71, 136–153 (2015)
Kabsch, W. Solution for best rotation to relate 2 sets of vectors. Acta Crystallogr. A 32, 922–923 (1976)
Collaborative Computational Project Number 4. The CCP4 suite: programs for protein crystallography. Acta Crystallogr. D 50, 760–763 (1994)
Tao, Y., Strelkov, S. V., Mesyanzhinov, V. V. & Rossmann, M. G. Structure of bacteriophage T4 fibritin: a segmented coiled coil and the role of the C-terminal domain. Structure 5, 789–798 (1997)
Abuladze, N. K., Gingery, M., Tsai, J. & Eiserling, F. A. Tail length determination in bacteriophage T4. Virology 199, 301–310 (1994)
Han, K. Y. et al. Solubilization of aggregation-prone heterologous proteins by covalent fusion of stress-responsive Escherichia coli protein, SlyD. Protein Eng. Des. Sel. 20, 543–549 (2007)
Leslie, A. G. W. & Powell, H. R. in Evolving Methods for Macromolecular Crystallography (eds Read, R. J. & Sussman, J. L. ) vol. 245, 41–51 (Springer, 2007)
Evans, P. Scaling and assessment of data quality. Acta Crystallogr. D 62, 72–82 (2006)
Evans, P. R. An introduction to data reduction: space-group determination, scaling and intensity statistics. Acta Crystallogr. D 67, 282–292 (2011)
Sheldrick, G. M. A short history of SHELX. Acta Crystallogr. A 64, 112–122 (2008)
Adams, P. D. et al. PHENIX: a comprehensive Python-based system for macromolecular structure solution. Acta Crystallogr. D 66, 213–221 (2010)
Brunet, Y. R., Zoued, A., Boyer, F., Douzi, B. & Cascales, E. The type VI secretion TssEFGK-VgrG phage-like baseplate is recruited to the TssJLM membrane complex via multiple contacts and serves as assembly platform for tail tube/sheath polymerization. PLoS Genet. 11, e1005545 (2015)
Sambrook, J. & Russell, D. W. Molecular Cloning: a Laboratory Manual (Cold Spring Harbor Laboratory Press, 2001)
Appleyard, R. K., McGregor, J. F. & Baird, K. M. Mutation to extended host range and the occurrence of phenotypic mixing in the temperate coliphage lambda. Virology 2, 565–574 (1956)
Clokie, M. R. J. & Kropinski, A. M. Bacteriophages: Methods and Protocols, (Humana Press, 2009)
Kucukelbir, A., Sigworth, F. J. & Tagare, H. D. Quantifying the local resolution of cryo-EM density maps. Nature Methods 11, 63–65 (2014)
Crooks, G. E., Hon, G., Chandonia, J. M. & Brenner, S. E. WebLogo: a sequence logo generator. Genome Res. 14, 1188–1190 (2004)
Krissinel, E. & Henrick, K. Inference of macromolecular assemblies from crystalline state. J. Mol. Biol. 372, 774–797 (2007)
We thank V. Mesyanshinov for developing the initial baseplate–tail tube complex purification protocol; C. Maillard for technical support; A. Brown for advice on structure refinement involving cryo-EM data; D. Demurtas for sample screening by negative stain EM; R. McLeod for help with data transfer; S. Nazarov, M. Plattner, and V. Kostyuchenko for discussions; and M. Basler for reading the manuscript. We acknowledge support from the EPFL SCITAS (high performance computing), the EPFL Centre for Interdisciplinary Electron Microscopy and the EPFL Proteomics Core Facility. The work was supported by the Swiss National Science Foundation grant 310030_144243.
The authors declare no competing financial interests.
Extended data figures and tables
a, Purification scheme of the T4 baseplate–tail tube complexes. b, SDS–PAGE of the sample used in cryo-EM imaging (the full gel is shown in Supplementary Fig. 1). c, Raw cryo-EM image of T4 baseplates. d, e, Representative reference-free 2D class averages of T4 baseplates in pre- and post-attachment conformations, respectively. The number of particles in each class in d is as follows: 1: 534; 2: 813; 3: 689; 4: 655; 5: 292; 6: 858; 7: 2,223; 8: 977. The number of particles in each class in e is as follows: 1: 315; 2: 68; 3: 494; 4: 60; 5: 263; 6: 387; 7: 62; 8: 566. f, g, Distribution of refined angles of the baseplate in both conformations. h, Fourier shell correlation (FSC) between independently refined maps calculated using half of the data (gold-standard refinement) after post-processing for both conformations. i, Fragments of the pre-attachment baseplate cryo-EM reconstruction map with fitted atomic model.
a, d, Resolution of pre- and post-attachment reconstructions analysed with ResMap83. b, e, Atomic models of pre- and post-attachment baseplates coloured by B-factors. c, Plots of the model-map FSC of the scrambled pre-attachment baseplate structure refined against half data map 1 from the gold-standard refinement versus half data map 1 (the map it was refined against) and half data map 2 (against which it was not refined). The absence of a large gap between both curves indicates that no excessive overfitting took place. f, As in c, but for the post-attachment baseplate. g, Localized cryo-EM refinement maps of the pre-attachment baseplate. h, FSC graphs of the localized refinements in g. i, Fit of gp9 into the pre-attachment baseplate map (the contour level is lower than that in Fig. 1a). j, Gaussian low-pass filtered (1/25 Å) raw images of individual baseplates attached to cell membranes selected from n = 243 similar images. Asterisks, baseplates; hash symbols, membranes. The extended STFs connecting the two can be seen.
a, Two structurally non-identical copies comprising the asymmetric unit of the ring are coloured yellow (gp6A) and red (gp6B). A neighbouring gp6A copy is coloured light brown. The rest of the ring is shown in light grey. The inset shows the position of the ring in the baseplate map. b, A close-up view of the gp6 subunits coloured in a. c, d, Close-up views of the N- and C-terminal gp6 dimers, respectively. In both views, the six-fold axis of the baseplate is roughly vertical.
a, Ribbon diagram of gp10 trimer and a schematic showing the general direction of the polypeptide chain in its four domains. The arrows also indicate the viewing direction in c. b, Traces of the three chemically identical polypeptide chains making up the complete gp10 molecule, which is shown as a semitransparent surface. c, Cross-sections through the four domains of gp10 in positions indicated with black lines in a. Note the switch of chain order around the three-fold axis between domains 2 and 3.
a, Structure and binding of gp10 domains 2 and 3 to the N-terminal domains of gp12 and gp11, respectively. The rightmost panel shows a superposition of the two complexes. b, The structure of gp10 domain 4. Cys555 and several other residues at strategic locations are labelled. Inset: a diagram explaining the complex knotted topology of gp10 domain 4. The gp10–gp10 and gp10–gp7 inter-chain disulfide bridges are indicated. c, d, Conservation of gp7 and gp10 amino acid sequences, respectively, is represented in the WebLogo format with letter heights proportional to the degree of conservation84. The conserved cysteines are highlighted with orange boxes. The numbers below the letters are positions in a multiple sequence alignment.
a, Ribbon diagram of the gp12 trimer, anchored to gp10 domain 2 (shown in surface representation). The N-terminal part of the fibre (residues 2–245) was built de novo. b, Structure of the gp12 repeat. c, Fold of the polypeptide chain making up the repeat. d, Evolutionary relationships between different T4 proteins comprising the baseplate’s periphery and fibres. The size of each bar is proportional to the amino acid sequence length. The gp12 repeat shown in b and c constitutes a major part of the proximal LTF protein gp34.
Determination of the structure of the wedge precursor on biophysical grounds (see Supplementary Information). a–c, Three possible precursors with a composition of (gp6)2–gp7–(gp8)2–(gp10)3 and association as found in the pre-attachment baseplate. d, Calculations with PISA85 favour the assembly shown in b. e, Size-exclusion chromatography of (TssE)1–(TssF)2–(TssG)1–(TssK)3 complex. f, 12% SDS–PAGE of (TssE)1–(TssF)2–(TssG)1–(TssK)3 complex. Numbers on the left are MW standards in kDa. Numbers in parentheses to the right of protein names are relative band intensities as quantified by Image Studio Lite (LI-COR) (the full gel is shown in Supplementary Fig. 1). g, Expression and purification of T4 gp25 in soluble form. Fraction 8 contains pure gp25 that was used for crystallization and structure determination. See Methods.
a, b, Location of the gp7 jump rope loop in the two conformations of the baseplate. c, The structure of gp7 is coloured by amino acid number from blue N terminus to white C terminus. The inset shows the position of gp7 (coloured blue) within the baseplate map. Interactions of gp7 with other baseplate proteins are shown schematically using the colour code of Fig. 1. The superscript i − 1 denotes interactions with a symmetry-related copy of a given protein. Red letters indicate sites of mutagenesis (for example, d/i636: deletion/insertion at position 636) that resulted in viable phage particles (see Supplementary Information). The purple label shows the site that tolerated neither residue deletion nor insertion. d, SDS–PAGE of purified T4-7am particles carrying the wild-type (WT) and five mutant gp7 proteins after their concentrations were brought to a common scale according to their absorbance at 260 nm (the full gel is shown in Supplementary Fig. 1). e, Infectivity of the mutant particles shown in d. The error bar indicates the 95% confidence interval obtained in three independent experiments (n = 3). Only one mutation was statistically significantly different from the rest and P-values (two-tailed Student’s t-test) comparing it to the wild-type phage and to the mutant with the largest experimental error are given.
a–c, Three different views of the inner and intermediate parts of two adjacent wedges (gp25, gp53, gp6 and gp7). Complete proteins are shown, including weakly conserved domains. The left and right columns represent the pre- and post-attachment baseplates, respectively. One of the two wedges (wedge I) is semi-transparent. In c, the central spike–tail tube complex is also displayed (semi-transparent). d, e, Transformation of the ring of the (gp6)2–gp7 trifurcation and gp6 dimerization domains from the pre- to the post-attachment state (as in Fig. 2d). The bars in d indicate the size of the fragment shown in e after rotation. f, Reorientation of the (gp6)2–gp7 core bundles.
a, b, Pseudoatomic model of the complete T4 tail in the extended (pre-attachment) and contracted (post-attachment) conformations. The insets show a close-up view (labelled with a black box) of the position of the gp18 subunit on the baseplate in the extended and contracted conformations of the sheath. The white geometrical shapes label the same regions of the sheath subunit in both conformations. c, Interaction of the two conserved domains of the gp18 sheath protein with the conserved components of the T4 baseplate wedge (as in Fig. 3). Coloured lines indicate the putative topology of the N- and C-terminal gp18 extensions, as well as the gp25 C-terminal strand. d, The same view as in c, but the external domain is now not shown for clarity to demonstrate the interaction of gp25-like sheath domains with each other and with gp25. e, f, The same as c and d but in the contracted state. g, h, Two diagrams demonstrating the motion of baseplate components that results in sheath contraction.
This file contains a Supplementary Discussion, Supplementary Tables 1-5 and Supplementary Figure 1 (uncropped gels). (PDF 3181 kb)
The intermediates were obtained by interpolating between the initial and final structure with the help of UCSF Chimera except for the motion and structure of the short tail fibers and the jump rope loop of gp7 (See text for details). The color code is as in Figure 1. NB: The conformational switch is irreversible and the reverse trajectories in this and all other animations are shown only for clarity of visualization. (MP4 29019 kb)
Baseplate conformational switch is accompanied by the release of the hub-tube complex from the conserved wedge proteins gp25 (light green), gp53 (pink), gp6 (yellow and red), and gp7 (blue).
Baseplate conformational switch is accompanied by the release of the hub-tube complex from the conserved wedge proteins gp25 (light green), gp53 (pink), gp6 (yellow and red), and gp7 (blue). (MP4 4019 kb)
Transformation of the iris formed by the (gp6)2-gp7 heterotrimers and gp6 C-terminal dimers during the baseplate conformational switch. Gp6 is in yellow and red and gp7 is in blue.
Transformation of the iris formed by the (gp6)2-gp7 heterotrimers and gp6 C-terminal dimers during the baseplate conformational switch. Gp6 is in yellow and red and gp7 is in blue. (MP4 4475 kb)
About this article
Cite this article
Taylor, N., Prokhorov, N., Guerrero-Ferreira, R. et al. Structure of the T4 baseplate and its function in triggering sheath contraction. Nature 533, 346–352 (2016). https://doi.org/10.1038/nature17971
This article is cited by
Nature Communications (2023)
Nature Communications (2023)
Nature Microbiology (2023)
Genome wide analysis revealed conserved domains involved in the effector discrimination of bacterial type VI secretion system
Communications Biology (2023)