High-titer production and purification of M13 bacteriophage for research and industrial applications. We ensure high viability and purity.
M13 bacteriophage is a filamentous virus that infects Gram-negative bacteria, specifically Escherichia coli (E. coli) strains housing the F plasmid. Discovered in 1963, M13 belongs to the Inoviridae family and is classified as an Ff phage (along with fd and f1), named for its specificity to the F pilus. Unlike lytic phages that burst and kill their host cells, M13 establishes a chronic infection. Progeny virions are continuously assembled and secreted through the bacterial membrane, slowing the host's growth rate but allowing it to survive and continue dividing. This unique non-lytic lifecycle is a cornerstone of its utility in biotechnology, particularly for high-titer phage production.
At Creative Biolabs, we leverage the M13 system to build comprehensive Phage Services for diverse applications spanning drug discovery, vaccine development, synthetic biology, and material science. In addition to M13, we provide resources on other phage systems:
The M13 virion is a flexible filament approximately 880–900 nm long and 6.5 nm in diameter. The genetic material is a circular single-stranded DNA (ssDNA) molecule of exactly 6407 nucleotides. The genome contains 9 genes that encode 11 distinct proteins, grouped by function: replication (pII, pV, pX), structural assembly (pI, pIV, pXI), and capsid formation.
Fig.1 M13 phage structure.1
The viral capsid is primarily composed of the pVIII major coat protein (encoded by gene VIII). Approximately 2,700 copies of pVIII form a helical tube around the central ssDNA core. pVIII is a small, amphipathic protein (50 amino acids) with a positively charged C-terminus that interacts electrostatically with the DNA inside the virion. While pVIII can be used for phage display (polyvalent display), the inserted peptide length is limited to 6–8 amino acids to avoid disrupting the capsid structure.
The filament ends are capped by minor coat proteins essential for infectivity and stability:
The M13 lifecycle is a sophisticated process occurring in four main stages, taking approximately 10 minutes to produce the first progeny, with secretion rates reaching 1,000 phage/cell in the first hour.
M13 is the gold standard for phage display. By fusing foreign DNA sequences to gene III or gene VIII, researchers create a physical link between genotype and phenotype. This allows for:
Beyond biology, the physical properties of M13 (high aspect ratio, monodispersity, and modifiable surface) make it a versatile scaffold for nanotechnology:
We provide a complete portfolio of services and products centered around the M13 platform.
High-titer production and purification of M13 bacteriophage for research and industrial applications. We ensure high viability and purity.
Supply of essential helper phages including M13KO7 and VCSM13 for efficient phagemid rescue and library screening.
Custom construction of M13-based display systems, optimizing linker sequences and fusion sites on pIII or pVIII.
Generation of large-scale Fab or scFv libraries using M13 phagemid vectors for the isolation of high-affinity binders.
We offer high-quality reagents to support your M13 research:
| Category | Product Type | Applications |
|---|---|---|
| M13 Antibodies | Anti-M13 pVIII (Clone UN-rj4), Anti-M13 pIII (Clone NN16) | ELISA, Western Blot, Flow Cytometry |
| DNA Detection | Anti-ssDNA / Anti-dsDNA Antibodies | Detection of RF or viral ssDNA |
| ELISA Kits | ssDNA/dsDNA ELISA Kits, M13 Titration Kits | Quantitative analysis of phage titer |
Q: What is the difference between M13 phage and M13KO7 helper phage?
Q: Why is M13 used for phage display instead of lytic phages?
A: M13 has a non-lytic lifecycle, meaning infected cells continue to grow and secrete phage particles into the culture medium. This allows for high-throughput screening and easy harvesting of phage clones without destroying the bacterial host. Additionally, the filamentous structure can accommodate DNA insertions of varying lengths within limits.
Q: Can M13 display large proteins?
A: Yes, M13 pIII protein can display large proteins such as scFv and Fab antibody fragments. However, large fusions to the major coat protein pVIII are generally limited to short peptides (6-8 amino acids) due to steric hindrance that can disrupt capsid assembly.
Q: What is the stability of M13 bacteriophage?
A: M13 is exceptionally stable. It can withstand temperatures up to 80°C, extreme pH levels, and exposure to various organic solvents. This robustness makes it an ideal candidate for nanotechnology applications and long-term storage.
Q: How do I store M13 phage stocks?
A: Phage stocks can be stored at 4°C for short periods (weeks to months). For long-term storage, mix the phage supernatant with glycerol to a final concentration of 15-50% and store at -80°C.
Q: Is M13 phage hazardous to humans?
A: No. M13 is a bacteriophage that specifically infects E. coli bacteria. It does not infect human, animal, or plant cells. It is generally classified as a Biosafety Level 1 (BSL-1) agent.
Q: What host strains are required for M13 infection?
A: M13 requires the bacterial F pilus for infection. Therefore, only F+ E. coli strains (containing the F plasmid or F' episome), such as XL1-Blue, TG1, or JM109, can be infected. It cannot infect F- strains.
Q: How can I concentrate M13 phage particles from the culture?
A: The standard method is precipitation using Polyethylene Glycol (PEG) and Sodium Chloride (NaCl). Adding PEG/NaCl to the culture supernatant and incubating on ice causes the phage particles to aggregate, which can then be pelleted by centrifugation.
Q: Does M13 phage form clear plaques?
A: No, M13 does not lyse (burst) the bacterial cells. Instead, it slows down the growth of infected cells. This results in "turbid" plaques—zones of reduced bacterial growth rather than clear zones of cell death seen with lytic phages.
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Please kindly note that our services can only be used to support research purposes (Not for clinical use).
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