Structural Insights into Lactococcal Siphophage p2 Baseplate Activation Mechanism
Virulent phages infecting <i>L. lactis</i>, an industry-relevant bacterium, pose a significant risk to the quality of the fermented milk products. Phages of the Skunavirus genus are by far the most isolated lactococcal phages in the cheese environments and phage p2 is the model siphophag...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-08-01
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| Series: | Viruses |
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| Online Access: | https://www.mdpi.com/1999-4915/12/8/878 |
| _version_ | 1827710385959993344 |
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| author | Silvia Spinelli Denise Tremblay Sylvain Moineau Christian Cambillau Adeline Goulet |
| author_facet | Silvia Spinelli Denise Tremblay Sylvain Moineau Christian Cambillau Adeline Goulet |
| author_sort | Silvia Spinelli |
| collection | DOAJ |
| description | Virulent phages infecting <i>L. lactis</i>, an industry-relevant bacterium, pose a significant risk to the quality of the fermented milk products. Phages of the Skunavirus genus are by far the most isolated lactococcal phages in the cheese environments and phage p2 is the model siphophage for this viral genus. The baseplate of phage p2, which is used to recognize its host, was previously shown to display two conformations by X-ray crystallography, a rested state and an activated state ready to bind to the host. The baseplate became only activated and opened in the presence of Ca<sup>2+</sup>. However, such an activated state was not previously observed in the virion. Here, using nanobodies binding to the baseplate, we report on the negative staining electron microscopy structure of the activated form of the baseplate directly observed in the p2 virion, that is compatible with the activated baseplate crystal structure. Analyses of this new structure also established the presence of a second distal tail (Dit) hexamer as a component of the baseplate, the topology of which differs largely from the first one. We also observed an uncoupling between the baseplate activation and the tail tip protein (Tal) opening, suggesting an infection mechanism more complex than previously expected. |
| first_indexed | 2024-03-10T17:37:14Z |
| format | Article |
| id | doaj.art-27d1d748c16a477ba77e62c3e9721711 |
| institution | Directory Open Access Journal |
| issn | 1999-4915 |
| language | English |
| last_indexed | 2024-03-10T17:37:14Z |
| publishDate | 2020-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Viruses |
| spelling | doaj.art-27d1d748c16a477ba77e62c3e97217112023-11-20T09:47:42ZengMDPI AGViruses1999-49152020-08-0112887810.3390/v12080878Structural Insights into Lactococcal Siphophage p2 Baseplate Activation MechanismSilvia Spinelli0Denise Tremblay1Sylvain Moineau2Christian Cambillau3Adeline Goulet4Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, Campus de Luminy, 13288 Marseille CEDEX 09, FranceDépartement de Biochimie, de Microbiologie, et de Bio-Informatique, Faculté des Sciences et de Génie, Université Laval, Québec, QC G1V 0A6, CanadaDépartement de Biochimie, de Microbiologie, et de Bio-Informatique, Faculté des Sciences et de Génie, Université Laval, Québec, QC G1V 0A6, CanadaArchitecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, Campus de Luminy, 13288 Marseille CEDEX 09, FranceArchitecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, Campus de Luminy, 13288 Marseille CEDEX 09, FranceVirulent phages infecting <i>L. lactis</i>, an industry-relevant bacterium, pose a significant risk to the quality of the fermented milk products. Phages of the Skunavirus genus are by far the most isolated lactococcal phages in the cheese environments and phage p2 is the model siphophage for this viral genus. The baseplate of phage p2, which is used to recognize its host, was previously shown to display two conformations by X-ray crystallography, a rested state and an activated state ready to bind to the host. The baseplate became only activated and opened in the presence of Ca<sup>2+</sup>. However, such an activated state was not previously observed in the virion. Here, using nanobodies binding to the baseplate, we report on the negative staining electron microscopy structure of the activated form of the baseplate directly observed in the p2 virion, that is compatible with the activated baseplate crystal structure. Analyses of this new structure also established the presence of a second distal tail (Dit) hexamer as a component of the baseplate, the topology of which differs largely from the first one. We also observed an uncoupling between the baseplate activation and the tail tip protein (Tal) opening, suggesting an infection mechanism more complex than previously expected.https://www.mdpi.com/1999-4915/12/8/878<i>bacteriophages</i><i>Lactococcus lactis</i><i>Siphoviridae</i>nanobodyelectron microscopyinfection mechanism |
| spellingShingle | Silvia Spinelli Denise Tremblay Sylvain Moineau Christian Cambillau Adeline Goulet Structural Insights into Lactococcal Siphophage p2 Baseplate Activation Mechanism Viruses <i>bacteriophages</i> <i>Lactococcus lactis</i> <i>Siphoviridae</i> nanobody electron microscopy infection mechanism |
| title | Structural Insights into Lactococcal Siphophage p2 Baseplate Activation Mechanism |
| title_full | Structural Insights into Lactococcal Siphophage p2 Baseplate Activation Mechanism |
| title_fullStr | Structural Insights into Lactococcal Siphophage p2 Baseplate Activation Mechanism |
| title_full_unstemmed | Structural Insights into Lactococcal Siphophage p2 Baseplate Activation Mechanism |
| title_short | Structural Insights into Lactococcal Siphophage p2 Baseplate Activation Mechanism |
| title_sort | structural insights into lactococcal siphophage p2 baseplate activation mechanism |
| topic | <i>bacteriophages</i> <i>Lactococcus lactis</i> <i>Siphoviridae</i> nanobody electron microscopy infection mechanism |
| url | https://www.mdpi.com/1999-4915/12/8/878 |
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