GroEL/ES mediated the in vivo recovery of TRAIL inclusion bodies in Escherichia coli

Essential factors, advanced strategies, challenges, and approaches involved for efficient expression of recombinant proteins in Escherichia coli

Producing recombinant proteins is a major accomplishment of biotechnology in the past century. Heterologous hosts, either eukaryotic or prokaryotic, are used for the production of these proteins. The utilization of microbial host systems continues to dominate as the most efficient and affordable method for biotherapeutics and food industry productions. Hence, it is crucial to analyze the limitations and advantages of microbial hosts to enhance the efficient production of recombinant proteins on a large scale. E. coli is widely used as a host for the production of recombinant proteins. Researchers have identified certain obstacles with this host, and given the growing demand for recombinant protein production, there is an immediate requirement to enhance this host. The following review discusses the elements contributing to the manifestation of recombinant protein. Subsequently, it sheds light on innovative approaches aimed at improving the expression of recombinant protein. Lastly, it delves into the obstacles and optimization methods associated with translation, mentioning both cis-optimization and trans-optimization, producing soluble recombinant protein, and engineering the metal ion transportation. In this context, a comprehensive description of the distinct features will be provided, and this knowledge could potentially enhance the expression of recombinant proteins in E. coli.

Engineering and Expression Strategies for Optimization of L-Asparaginase Development and Production

Genetic engineering for heterologous expression has advanced in recent years. Model systems such as Escherichia coli, Bacillus subtilis and Pichia pastoris are often used as host microorganisms for the enzymatic production of L-asparaginase, an enzyme widely used in the clinic for the treatment of leukemia and in bakeries for the reduction of acrylamide. Newly developed recombinant L-asparaginase (L-ASNase) may have a low affinity for asparagine, reduced catalytic activity, low stability, and increased glutaminase activity or immunogenicity. Some successful commercial preparations of L-ASNase are now available. Therefore, obtaining novel L-ASNases with improved properties suitable for food or clinical applications remains a challenge. The combination of rational design and/or directed evolution and heterologous expression has been used to create enzymes with desired characteristics. Computer design, combined with other methods, could make it possible to generate mutant libraries of novel L-ASNases without costly and time-consuming efforts. In this review, we summarize the strategies and approaches for obtaining and developing L-ASNase with improved properties.

Current state of molecular and metabolic strategies for the improvement of L-asparaginase expression in heterologous systems

Heterologous expression of L-asparaginase (L-ASNase) has become an important area of research due to its clinical and food industry applications. This review provides a comprehensive overview of the molecular and metabolic strategies that can be used to optimize the expression of L-ASNase in heterologous systems. This article describes various approaches that have been employed to increase enzyme production, including the use of molecular tools, strain engineering, and in silico optimization. The review article highlights the critical role that rational design plays in achieving successful heterologous expression and underscores the challenges of large-scale production of L-ASNase, such as inadequate protein folding and the metabolic burden on host cells. Improved gene expression is shown to be achievable through the optimization of codon usage, synthetic promoters, transcription and translation regulation, and host strain improvement, among others. Additionally, this review provides a deep understanding of the enzymatic properties of L-ASNase and how this knowledge has been employed to enhance its properties and production. Finally, future trends in L-ASNase production, including the integration of CRISPR and machine learning tools are discussed. This work serves as a valuable resource for researchers looking to design effective heterologous expression systems for L-ASNase production as well as for enzymes production in general.

[Approaches for improving L-asparaginase expression in heterologous systems]

L-asparaginase (EC 3.5.1.1) is one of the most demanded enzymes used in the pharmaceutical industry as a drug and in the food industry to prevent the formation of toxic acrylamide. Researchers aimed to improve specific activity and reduce side effects to create safer and more potent enzyme products. However, protein modifications and heterologous expression remain problematic in the production of asparaginases from different species. Heterologous expression in optimized producer strains is rationally organized; therefore, modified and heterologous protein expression is enhanced, which is the main strategy in the production of asparaginase. This strategy solves several problems: incorrect protein folding, metabolic load on the producer strain and codon misreading, which affects translation and final protein domains, leading to a decrease in catalytic activity. The main approaches developed to improve the heterologous expression of L-asparaginases are considered in this paper.

GroEL—A Versatile Chaperone for Engineering and a Plethora of Applications

Chaperones play a vital role in the life of cells by facilitating the correct folding of other proteins and maintaining them in a functional state, being themselves, as a rule, more stable than the rest of cell proteins. Their functional properties naturally tempt investigators to actively adapt them for biotechnology needs. This review will mostly focus on the applications found for the bacterial chaperonin GroE and its counterparts from other organisms, in biotechnology or for research purposes, both in their engineered or intact versions.

Effect of the ACY-1 gene on HER2 and TRAIL expression in rectal carcinoma

The incidence of rectal carcinoma (RC) is increasing and the age at onset of the disease is reducing. Therefore, elucidating the pathogenesis of RC is beneficial for early diagnosis and improving the prognosis. Aminoacylase-1 (ACY-1) is abnormally expressed in various malignant tumor tissues. Furthermore, the human epidermal growth factor receptor-2 (HER2) gene is involved in tumor metastasis and invasion, while tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces tumor cell apoptosis. The aim of the present study was to investigate the effect of the ACY-1 gene on the expression of HER2 and TRAIL in RC. Cancerous and adjacent tissues from RC patients were collected. ACY-1 expression was analyzed by immunohistochemistry. The rectal cancer cell lines HT29 and SW620, and normal colorectal mucosal epithelial fetal human cells were cultured in vitro. ACY-1 gene and protein expression levels were tested by reverse transcription-quantitative PCR and western blotting. ACY-1 small interfering RNA (siRNA) was transfected into HT29 and SW620 cells. Cell proliferation was detected by thiazolyl blue MTT assay. Caspase-3 activity was assessed using a commercial kit. HER2 and TRAIL expression levels were determined by western blotting. ACY-1 expression was significantly increased in cancer tissue compared with adjacent tissue (P<0.05). ACY-1 expression was elevated in HT29 and SW620 cells compared with normal colorectal mucosal epithelial cells (P<0.05). ACY-1 siRNA transfected into HT29 cells downregulated its expression, inhibited cell proliferation, enhanced caspase-3 activity, reduced HER2 expression and upregulated TRAIL expression (P<0.05). ACY-1 expression was found to be increased in rectal cancer tissue. Therefore, targeting the ACY-1 gene may regulate HER2 and TRAIL expression levels, and may reduce the occurrence and inhibit the development of rectal cancer.

A Review: Molecular Chaperone-mediated Folding, Unfolding and Disaggregation of Expressed Recombinant Proteins

The advancements in biotechnology over time have led to an increase in the demand of pure, soluble and functionally active proteins. Recombinant protein production has thus been employed to obtain high expression of purified proteins in bulk. E. coli is considered as the most desirable host for recombinant protein production due to its inexpensive and fast cultivation, simple nutritional requirements and known genetics. Despite all these benefits, recombinant protein production often comes with drawbacks, such as, the most common being the formation of inclusion bodies due to improper protein folding. Consequently, this can lead to the loss of the structure-function relationship of a protein. Apart from various strategies, one major strategy to resolve this issue is the use of molecular chaperones that act as folding modulators for proteins. Molecular chaperones assist newly synthesized, aggregated or misfolded proteins to fold into their native conformations. Chaperones have been widely used to improve the expression of various proteins which are otherwise difficult to produce in E. coli. Here, we discuss the structure, function, and role of major E. coli molecular chaperones in recombinant technology such as trigger factor, GroEL, DnaK and ClpB.

A simplified method for the efficient purification and refolding of recombinant human TRAIL

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) belongs to the TNF cytokine superfamily that specifically induces apoptosis in a broad spectrum of human cancer cell lines but not in most healthy cells. The antitumor potential of recombinant human TRAIL (rhTRAIL) has attracted great attention among biologists and oncologists. However, attempts to express rhTRAIL in Escherichia coli often results in limited yield of bioactive protein due to the formation of inclusion bodies (IBs), which are dense insoluble particulate protein aggregates inside cells. We describe herein a highly simplified method to produce pure bioactive rhTRAIL using E. coli. The method is straightforward and requires only basic laboratory equipment, with highly efficient purification and high yield of renaturation, and may also be applied to produce other proteins that form IBs in E. coli.