Difference between revisions of "Team:Aix-Marseille/Bacteriophages"
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M13 is a filamentous phage that infects E. coli that carry the F-episome. It is composed of a circular single-stranded DNA molecule encapsided in a thin flexible tube composed of multiple copies of the same protein. Infection starts when the minor coat protein P3 attaches to F pilus of the bacterium. Active infection with M13 does not kill the host cell. | M13 is a filamentous phage that infects E. coli that carry the F-episome. It is composed of a circular single-stranded DNA molecule encapsided in a thin flexible tube composed of multiple copies of the same protein. Infection starts when the minor coat protein P3 attaches to F pilus of the bacterium. Active infection with M13 does not kill the host cell. | ||
| − | [[ | + | {{Aix-Marseille|title=M13 phage|toc=__TOC__}} |
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| + | ===Life cycle=== | ||
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| + | [[File:T--Aix-Marseille--M13LCb.png|300px|right|thumb|M13 phage life cycle in ''Escherichia coli''.]] | ||
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| + | The M13 life cycle begins with passage of the phage genome into a host cell in a process induced by protein III (pIII). First, the single-strand DNA (ssDNA) is converted in double-strand DNA (dsDNA) by pII and pX, which allow the production of phage's protein. | ||
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| + | After a while, as the concentrations of phage proteins increase and the ssDNA is back converted as dsDNA. The protein V (pV) binds to the ssDNA genomes for packaging into progeny phages. It recognise the single stranded M13 origin of replication. The pV-sequestered ssDNA is recognized by the membrane spanning phage assembly complex. <ref name=Smeal>Smeal, S. W., Schmitt, M. A., Pereira, R. R., Prasad, A. & Fisk, J. D. Simulation of the M13 life cycle I: Assembly of a genetically-structured deterministic chemical kinetic simulation. Virology 500, 259–274 (2017).</ref> | ||
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| + | ===Protein III=== | ||
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| + | [[File:T--Aix-Marseille--M13p3b.png|400px|right|thumb|Description of the domains composing M13's protein III.]] | ||
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| + | The molecular interactions that mediate the entry of ''Escherichia coli'' derived filamentous phages into their hosts have been studied in considerable detail. The 424-amino-acid protein III is thought to consist of a leader sequence and three domains, separated by glycine-rich regions, that serve distinct roles in phage entry and release. The first two pIII domains, D1 and D2, are required for M13 adsorption and entry, while the third domain D3 is required for the assembly and release of M13 particles from host.<ref name="Heilpern">Heilpern, A. J. & Waldor, M. K. pIIICTX, a predicted CTXphi minor coat protein, can expand the host range of coliphage fd to include Vibrio cholerae. J. Bacteriol. 185, 1037–1044 (2003).</ref> | ||
==Phages-like particules design== | ==Phages-like particules design== | ||
Revision as of 11:22, 27 September 2017
Engineering bacteriophages
Bacteriophages play a special role in nanoscale cargo-delivery developments, because they can be regarded as naturally occurring nanomaterials. Viral nanoparticles (VNPs), in particular bacteriophages, are attractive options for cargo-delivery as they are biocompatible, biodegradable, and non-infectious to mammals.
Phage systems, like M13, have been employed in biotechnological applications, most prominently in the identification and maturation of medically-relevant binding molecules through phage display. The application of phages in materials and nanotechnology is mainly due to their nanoscale size and simple life cycles. We choose to use those application in our advantage in order to target Xylella fastidiosa and other pathogenic bacteria.
M13 phages
M13 is a filamentous phage that infects E. coli that carry the F-episome. It is composed of a circular single-stranded DNA molecule encapsided in a thin flexible tube composed of multiple copies of the same protein. Infection starts when the minor coat protein P3 attaches to F pilus of the bacterium. Active infection with M13 does not kill the host cell.
M13 phage
Life cycle
The M13 life cycle begins with passage of the phage genome into a host cell in a process induced by protein III (pIII). First, the single-strand DNA (ssDNA) is converted in double-strand DNA (dsDNA) by pII and pX, which allow the production of phage's protein.
After a while, as the concentrations of phage proteins increase and the ssDNA is back converted as dsDNA. The protein V (pV) binds to the ssDNA genomes for packaging into progeny phages. It recognise the single stranded M13 origin of replication. The pV-sequestered ssDNA is recognized by the membrane spanning phage assembly complex. [1]
Protein III
The molecular interactions that mediate the entry of Escherichia coli derived filamentous phages into their hosts have been studied in considerable detail. The 424-amino-acid protein III is thought to consist of a leader sequence and three domains, separated by glycine-rich regions, that serve distinct roles in phage entry and release. The first two pIII domains, D1 and D2, are required for M13 adsorption and entry, while the third domain D3 is required for the assembly and release of M13 particles from host.[2]
Phages-like particules design
Bacteriophages are capable of expressing their genomes, and generating new copies of themselves. We choose to limit the phage ability to reproduce itself in order to contain it. As it is possible to produce recombinant viruses that express foreign proteins, it is possible to restrain their capacity to reproduce themself. [3]
Virus-like particles (VLPs) are multiprotein structures that mimic the organization and conformation of authentic native viruses but lack the viral genome. They have been applied not only as prophylactic and therapeutic vaccines but also as vehicles in drug and gene delivery and, more recently, as tools in nanobiotechnology. [3]
In this project, we want to creat a M13-like phage like particle, in order to inject toxin in the bacterium.
References
- ↑ Smeal, S. W., Schmitt, M. A., Pereira, R. R., Prasad, A. & Fisk, J. D. Simulation of the M13 life cycle I: Assembly of a genetically-structured deterministic chemical kinetic simulation. Virology 500, 259–274 (2017).
- ↑ Heilpern, A. J. & Waldor, M. K. pIIICTX, a predicted CTXphi minor coat protein, can expand the host range of coliphage fd to include Vibrio cholerae. J. Bacteriol. 185, 1037–1044 (2003).
- ↑ 3.0 3.1 Roldão, A., Silva, A. C., Mellado, M. C. M., Alves, P. M. & Carrondo, M. J. T. Viruses and Virus-Like Particles in Biotechnology: Fundamentals and Applications. in Reference Module in Life Sciences (Elsevier, 2017).
