Updated: Mar 7
Protein expressions and systems refer to the unique ability to regulate, alter, or integrate proteins of a designated live organism. When it comes to proteins and research, this expression process can refer to the distinct laboratory methods used or the purpose of analysis.
Understanding the expression measures, cellular options, and techniques available plays a fundamental role in ensuring timely, affordable, and optimal protein delivery for a given application. In this article, we explore an ultimate guide to protein expression systems and how each offers advantages or disadvantages based on demand.
A Detailed Look at Protein Expression
Protein services outline a series of functional cell requirements that control and generate the protein production process. The core DNA housing the protein's blueprints are the messenger RNA's foundation during transcription. This messenger RNA, or mRNA, becomes the primary carrier for the amino acids that produce the proteins during service.
Transcription and translation are two processes that may occur simultaneously or independently depending on the flow of DNA. In the case of prokaryotes, transcription and translation occur simultaneously. For eukaryotes, these processes are individual and based on synthesis. Eukaryotic transcriptions occur in the nucleus, while translation occurs in the cytoplasm. We explore these protein expression system processes in more depth below.
Transcription and Translation in More Depth
Prokaryotes and eukaryotes experience transcription through the same three processes: initiation, elongation, and termination. Double-stranded DNA unravels at the beginning of transcription. This unraveling creates the time and space for RNA polymerase to bind—the RNA polymerase releases during this initial transcription phase. The transcription process experiences regulation with the help of repressors, activators, and eukaryote chromatin.
When we look at prokaryotes, the messenger RNA experiences translation well before the transcription process ends, and no additional modifications are necessary for the process. When genes experience transcription and translation concurrently, this is known as coupling. In contrast, eukaryotic cells take a different approach, requiring transcription and translation to occur individually to meet the protein production service demands.
In a eukaryotic approach, a series of posttranslational alterations occur to assist in final structurization. Posttranslational modifications, or PTMs, include changes and modifications to newly created proteins to achieve the intended results. PTMs play a fundamental role in cell biology, as well as in peptide synthesis.
Protein Expression Systems
Protein expression and purification systems play a significant role in application success. The expression system must include various criteria to achieve the intended results, including yields, speed of purification, the solubility of a protein, and overall functionality. Prior to determining the best expression system, each system's pros and cons should be carefully considered.
Below we discuss the pros and cons of each expression system to help you determine the best custom protein production technique for your desired results. We explore the various host cells used for expression production and offer clear insight into their unique delivery processes.
Bacterial Expression System
The bacterial expression system is ideal for low-cost services looking to scale production. E. coli is one of the most preferred hosts, with a rapid turnaround time. Bacterial cultures are simple to grow with a quick culture period.
The con to bacterial expression systems is the lack of compatibility with posttranslational modifications. Bacteria expressions exhibit non-functional characteristics which inhibit their ability to accommodate the necessary molecular folding in PTMs.
Yeast Expression System
Yeast expression systems offer a unique ability to use distinct eukaryotic cell processing, allowing optimal posttranslational modifications with high yield rates. Most often, yeast expression services help create functional and structural analysis, antibody generation and production, and distinct protein interactions.
A fermentation process is vital for achieving high yields; some argue this is a con in the process's delivery timeframe. Due to the possibility of a fermentation demand, the growing conditions vary and may require further optimization.
Mammalian Expression System
Compared to bacterial expressions, mammalian expression systems allow optimal posttranslational modifications with higher yields, though this can become more costly. The advantage of a mammalian expression is the distinct functionality created through the PTMs and the structure of the environment carried out through the physiological nature.
Mammalian expressions are widely preferred for antibody production, high-functioning cells, and proteins with high complexity volumes. Though these characteristics offer great benefits, these traits do not come without increased cultural demands.
Insect Expression System
Insect expression systems are also another form of highly preferred production proteins. Insect cells are highly efficient and compatible with eukaryotic machinery and can produce relatively large intracellular and common proteins.
A con to insect expression systems is the length of time necessary to create the virus, which extends overall production time to eight or more weeks. Compared to prokaryotic systems, the production demands for an insect expression eukaryotic system require demanding culture conditions. However, it's worth noting that insect expression systems are scalable for increased production demands and include high-density cultures if necessary.
Cell-Free and Algal Expressions
While cell-free and algal expression systems do not fall into the scope of practice for Bon Opus Biosciences, they are two other available forms of expression. Cell-free expressions use toxic proteins and require a translational inhibitor screening before further steps. The formatting is simple with a rapid expression time. Cell-free expression systems are compatible with unnatural compounds due to the protein's molecular nature. A significant disadvantage of a cell-free expression is how unattainable large-scale production is.
Algal expression systems use the study of plant biology and photosynthesis, in addition to genetic and biofuel production and engineering. Algal expression is underdeveloped when compared to other host cell production systems, though it is advantageous when exploring genetic alterations in microalgae photosynthesis.
Bon Opus Biosciences delivers this ultimate guide to protein expression systems supported by affordable and custom services. We feature custom recombinant protein production services tailored to serve a wide variety of applications and host cells. Connect with our team to learn about our protein services and more.