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-Structure paper
タイトル | Three-dimensional structure of the toxin-delivery particle antifeeding prophage of Serratia entomophila. |
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ジャーナル・号・ページ | J Biol Chem, Vol. 288, Issue 35, Page 25276-25284, Year 2013 |
掲載日 | 2013年8月30日 |
著者 | J Bernard Heymann / Joseph D Bartho / Daria Rybakova / Hari P Venugopal / Dennis C Winkler / Anindito Sen / Mark R H Hurst / Alok K Mitra / |
PubMed 要旨 | The Serratia entomophila antifeeding prophage (Afp) is a bullet-shaped toxin-delivery apparatus similar to the R-pyocins of Pseudomonas aeruginosa. Morphologically it resembles the sheathed tail of ...The Serratia entomophila antifeeding prophage (Afp) is a bullet-shaped toxin-delivery apparatus similar to the R-pyocins of Pseudomonas aeruginosa. Morphologically it resembles the sheathed tail of bacteriophages such as T4, including a baseplate at one end. It also shares features with the type VI secretion systems. Cryo-electron micrographs of tilted Afp specimens (up to 60 degrees) were analyzed to determine the correct cyclic symmetry to overcome the limitation imposed by exclusively side views in nominally untilted specimens. An asymmetric reconstruction shows clear 6-fold cyclic symmetry contrary to a previous conclusion of 4-fold symmetry based on analysis of only the preferred side views (Sen, A., Rybakova, D., Hurst, M. R., and Mitra, A. K. (2010) J. Bacteriol. 192, 4522-4525). Electron tomography of negatively stained Afp revealed right-handed helical striations in many of the particles, establishing the correct hand. Higher quality micrographs of untilted specimens were processed to produce a reconstruction at 2.0-nm resolution with imposed 6-fold symmetry. The helical parameters of the sheath were determined to be 8.14 nm for the subunit rise along and 40.5° for the rotation angle around the helix. The sheath is similar to that of the T4 phage tail but with a different arrangement of the subdomain of the polymerizing sheath protein(s). The central tube is similar to the diameter and axial width of the Hcp1 hexamer of P. aeruginosa type VI secretion system. The tube extends through the baseplate into a needle resembling the "puncture device" of the T4 tail. The tube contains density that may be the toxin and/or a length-determining protein. |
リンク | J Biol Chem / PubMed:23857636 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 19.0 - 20.0 Å |
構造データ | EMDB-2419: EMDB-2423: |
由来 |
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