KMD Bioscience Co., Ltd.
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2023-12-07 Hits(172)
Phage display technology is a powerful molecular tool that has played a significant role in biotechnology and medical research since the late 1980s. The characteristic of phages is to infect bacteria and other microbes, using their cells for self-replication. Phage display systems utilize this feature of phages by inserting exogenous proteins or peptides into the phage genome, enabling the phage to express and display these exogenous proteins or peptides. The applications of phage display technology are extensive, ranging from drug development to vaccine design, and to the development of diagnostic tools. The origins of phage display technology can be traced back to 1985 when George P. Smith first demonstrated that exogenous peptides could be displayed on the surface of a phage. This technology quickly gained widespread use in the fields of molecular biology and protein engineering, becoming a powerful tool for studying protein-protein interactions, antigenic epitope mapping, and antibody engineering.
Figure 1: Classification of Phage Display Systems
In phage display technology, different types of phage systems have their unique characteristics, mainly including the M13 phage, and T7 and T4 phage systems. These systems vary in protein display diversity, stability, and efficiency, and are suitable for different research and application needs. This article will focus on discussing the similarities and differences of the M13, T7, and T4 phage display systems.
M13 Phage Display System: The M13 phage mainly uses pIII and pVIII coat proteins to construct its display system. pIII is located at one end of the phage particle and can insert larger molecular weight exogenous peptides/proteins at its N-terminal flexible linker region, thus suitable for displaying larger proteins. pVIII is primarily distributed on the sides of the phage particle, smaller in molecular weight with more copies, and thus is only suitable for displaying exogenous short peptides, currently mainly used for screening low-affinity ligands.
T4 Phage Display System: The T4 phage is often used to study complex proteins that cannot be secreted by E. coli, as its viral particles are assembled inside the host cell, thus allowing the display of various peptides or proteins without the need for a secretion pathway. In addition, the coat proteins of T4 phage have two binding sites, SOC and HOC sites, allowing the phage to fuse and simultaneously display two different types of exogenous peptides/proteins on its surface, with a higher number of display copies.
T7 Phage Display System: The coat protein commonly used to construct the phage display system in T7 phage is 10B. Compared to M13, it does not require secretion and can directly lyse the host bacteria. Therefore, it is suitable for displaying peptides/proteins that have inhibitory effects on the secretion process, which cannot be displayed in the M13 system. Moreover, T7 phage is produced very rapidly, saving a lot of time and facilitating research.
The following table compares and elaborates on the characteristics, diversity, stability, and assembly efficiency of the three different phage display systems:
Table 1: Comparison of Several Different Phage Display Systems:
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M13 phage is a filamentous phage that mainly infects Escherichia coli. Its greatest feature is that it can replicate without killing host cells, which makes it continuous and efficient in protein display. |
T7 phage is a head-to-tail phage that replicates and produces proteins relatively quickly. The T7 system can quickly generate large quantities of phage particles, making it an efficient protein display platform. |
T4 phage is able to accommodate and display relatively large protein or peptide sequences due to its large genome capacity. This system is suitable for applications where larger proteins or complex peptide structures need to be displayed. For example, the T4 phage display system provides an effective platform when studying large proteins that require the cooperation of multiple domains. |
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M13 phage is suitable for displaying relatively small peptides and proteins. This system is particularly useful for displaying small peptides that need to be displayed in the correct conformation. |
Compared with M13 phage, T7 phage is more suitable for displaying larger proteins or complex peptides. This system is more tolerant of protein size. |
T4 phage is able to accommodate and display relatively large protein or peptide sequences due to its large genome capacity. This system is suitable for applications where larger proteins or complex peptide structures need to be displayed. |
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Peptides or proteins displayed by M13 phage usually have good stability, especially during the continuous culture and screening process. |
The protein displayed by T7 phage is also more stable, but due to its shorter life cycle, more frequent cultivation and screening may be required. |
Although the replication method of T4 phage results in host cell lysis, the displayed protein or polypeptide can usually maintain good stability during its replication process. When performing phage-mediated protein display, T4 phage can ensure high efficiency while maintaining the structural and functional integrity of the target protein. | |
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The M13 phage system is very effective in screening for specific proteins or peptides, especially when performing large-scale screening. |
T7 phage excels at rapid production and expression of target proteins, making it suitable for applications requiring high-throughput screening. |
T4 phage shows high efficiency in the construction and screening of large-scale protein libraries. Due to lytic replication during its life cycle, T4 phage is able to generate a large number of phage particles containing target proteins in a relatively short time, which makes it excellent in high-throughput screening and large-scale protein production. |
M13 and T7 phage systems each have advantages and limitations in display diversity, stability and efficiency. Which system to choose depends on the specific experimental goals and needs. The M13 system is more suitable for the display and long-term screening of small molecule peptides, while the T7 system has advantages in rapid expression and high-throughput screening of large molecule proteins. Proper selection of the appropriate phage system is critical to ensure experimental success and reliable results. The T4 phage system offers a unique option in protein display technology, especially when working with large proteins or performing high-throughput screening. KMD Bioscience can provide library construction services based on M13 and T7 phage display systems:
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