T4 Phage Library Construction Services

As a long-term undisputed global pioneer in the field of phage display, Creative Biolabs has developed a comprehensive service portfolio based on our state-of-the-art technical platforms. Currently, Creative Biolabs is pleased to offer this exclusive service of T4 phage display library construction to our customers around the world.

Fig.1 A scanning electron
micrograph of T4 phage.

First established in the 1980s, phage display has been a pivotal laboratory technique widely utilized in a variety of research fields, including antibody engineering, drug discovery, vaccine design, epitope mapping, and so on. By displaying certain molecules on the surface of genetically modified phages, a direct connection between genotype and phenotype can be formed, thus enabling the high-throughput analysis of vast amount of variants. Comparing with the most widely used filamentous phage system (i.e. M13), T4 phage display system also provides a promising alternative for its special merits.

Bacteriophage T4 is distinct from M13 in many aspects. T4 is of much larger size, tailed structure and double-stranded DNA (dsDNA) genome encoding 50 different proteins. Based on the appearance, T4 phage is divided into three parts: a head, a fistulous and contractile neck for DNA injection and a tail part for recognizing and binding to the bacteria surface. The viral head, where T4 preserves its DNA, has an icosahedral structure mainly composed of three coat proteins: gp23, gp24 and gp20. In addition, there exist two non-essential proteins, HOC and SOC, decorated on the icosahedral head together with other coat proteins. In addition, T4 undergoes an exclusively lytic lifecycle, which is different with M13, meaning that after infection progeny phage particles are assembled in the cytoplasm and released by lysis of the host bacterium.

Fig 2. Structure of the bacteriophage T4 head (Rao and Black 2010)

T4 phage display system employs two dispensable capsid proteins, HOC and SOC, to genetically fuse with exogenous sequences thus displaying the specific molecules on the head surface. Both N- and C-termini are accessible to foreign insertions without impacting the infectivity and viability of T4. Furthermore, T4 phages have a lytic lifecycle without going through membrane extraction process, which might limit the insertion size, affect the protein confirmation as well as cause toxicity to the host. Hence, T4 display system can provide an optimized solution to overcome the main barriers of M13 phage display.

Three available approaches for T4 library construction:

Generally, T4 phage display system can offer major advantages over other display systems including:

Larger genome DNA which enables larger insertions
High display density
Dual display: two different molecules can be displayed separately on HOC and SOC
Both N- and C-terminal insertion available
No membrane secreting process, avoiding host toxicity and confirmation changes
Multiple choices of host bacteria strain besides E. coli

T4 phage display has revealed great potential in various research and pharmaceutical fields, especially multicomponent vaccine development. It provides a promising alternative when conventional M13 phage display does not work well. With our extensive experience and unparalleled technologies after years of accumulation, Creative Biolabs has confidence in bringing professional services based on T4 phage display systems, assisting our clients to pave the way to revolutionary scientific progress.

Reference

Rao, V. B. and Black, L. W. (2010) 'Structure and assembly of bacteriophage T4 head', Virology journal, 7(1), 1.

All listed services and products are For Research Use Only. Do Not use in any diagnostic or therapeutic applications.

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