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Image of protein molecule in lab setting for article on protein expression and purification.
Published On: July 27th, 2021

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Whether human, plant, or bacteria, proteins play a vital role in every living cell’s structure and function in our universe.

Proteins were first discovered in 1838 by the Swedish chemist Jöns Jacob Berzelius who recognized the critical importance of these substances for life. Consequently, he chose the name protein, which comes from the Greek word for “holding first place.”

The DNA in the nucleus of cells provides the codes for individual amino acids, which combine to form large protein molecules. How the cell translates the instructional DNA molecule in its nucleus to a fully formed complex protein produced in the cytoplasmic ribosomes continues to be an area of immense study, with much of the steps now understood.Read on to learn more about the basics of expressing and purifying proteins.

What is Protein Expression and Purification?

In its simplest form, a protein is a long chain of connected amino acids, one after another. This is termed its primary structure. Ultimately, however, proteins fold into very complex 3-dimensional conformations with various segments attracting or repelling each other. Secondary, tertiary, or quaternary structures are used to identify the different segments of a protein molecule that fold itself into a highly complex 3-dimensional structure.

Once a protein is expressed or created in the laboratory, it must be purified so that the desired protein or proteins are separated from any other organically active molecules.This is necessary to ensure that the experiment and results are due to the desired protein and not contamination. Also, suppose the finished product (i.e., purified protein) does not have a high enough concentration of the desired protein. In that case, the measurements and results will either be too small to interpret or lead to erroneous results.

How is Protein Expression and Purification Performed in the Laboratory?

Protein Expression

Since 1982 and the discovery of the polymerase chain reaction (PCR) for rapid and controlled DNA duplication, the creation of quantitative polymerase chain reaction (qPCR) labs has enabled scientists to direct the multiplication of any length of DNA. This control allows the scientist to specify which proteins are to be produced in the lab and in what quantities. Fundamentally, this is the process of qPCR.

Protein Purification

Whether the desired proteins are extracted from living cells or created in a qpcr lab, there will many other biological components mixed with the desired protein. By identifying the sample protein’s physical and chemical characteristics, methods like centrifugation and electrophoresis can be used to separate the desired protein from other proteins, lipids, carbohydrates, and nucleic acids. Ultimately, the goal is to have your calculated volume of the specified protein without any other biological material.

The Bottleneck of Protein Expression and Purification

With the explosion of PCR and its relatives (e.g., qPCR, RT-PCR, RT-qPCR), laboratories have been eager to find ways to speed the process of expressing and purifying proteins. Experiments in most laboratories are not moving as rapidly as possible when manual techniques are used for protein expression and purification, leading to a backlog of experiments waiting to be done.

The Solution to Protein Expression and Purification

Automation has proven to be the answer to the bottleneck.

Laboratories that use automation for performing PCR protocols can complete experiments in a significantly shorter time, allowing for more experiments to be concluded, analyzed, and published in the laboratory. Automated machines do everything from plating cells to adding reagents to regulating precision temperature cycles (time and temperature) for DNA amplification.

Protein Expression and Purification: Total Laboratory Automation

While automation has made protein expression and purification faster and more reliable with greater flexibility, the constant advances in automation hold every lab’s promise adopting Total Laboratory Automation (TLA).

The advantages of TLA in protein expression and purification, which many labs have already achieved, are numerous. Turnaround times from initial experimental design to final results have been slashed. While the initial expense of TLA can be high, long-term costs are substantially lower than traditional laboratory methods.

There remain some issues for TLA that still need to be overcome, such as the need for adequate lab space and the risk of downtime if automated machinery is unreliable. But with the ever-diminishing size and ever-increasing reliability of microchip technology, no issue is insurmountable for every lab that desires to have Total Laboratory Automation.
Contact us today to request a consultation or to learn more about our host of products to assist you with Protein Expression and Purification and to discover new automation options to meet all of your laboratory needs.