The molecular weight of a protein can significantly impact its expression in various expression systems. Here are several ways in which protein molecular weight can influence expression:

1. Expression Yield:

• Smaller Proteins: Generally, smaller proteins are easier to express and tend to yield higher amounts. They are less likely to form inclusion bodies and can often be produced efficiently in simpler systems like bacteria.
• Larger Proteins: Larger proteins can be more challenging to express. They may be prone to misfolding and aggregation, resulting in lower yields. Larger proteins often require more sophisticated systems (e.g., mammalian or insect cells) that can provide the necessary chaperones and folding machinery.

2. Folding and Solubility:

• Smaller Proteins: These proteins typically fold more easily and are more likely to be soluble, reducing the need for extensive refolding processes.

• Larger Proteins: Larger proteins have more complex folding pathways and are more susceptible to misfolding and aggregation. This can lead to the formation of inclusion bodies in bacterial systems, necessitating the use of solubilization and refolding strategies.
  

3. Post-Translational Modifications:

• Smaller Proteins: These often have fewer post-translational modification sites, making them easier to express in systems that lack complex modification capabilities (e.g., bacteria).
  
• Larger Proteins: Larger proteins usually have more post-translational modification sites (e.g., glycosylation, phosphorylation). Systems that provide these modifications (e.g., mammalian or insect cells) are often required to ensure proper protein function and stability.
  

4. Expression System Suitability:

• Bacterial Systems: Best suited for small to medium-sized proteins. Large proteins often face challenges with folding and solubility.
  
• Yeast Systems: Can handle moderate-sized proteins and provide some post-translational modifications. However, very large proteins may still present challenges.
  
• Mammalian and Insect Systems: Capable of expressing large and complex proteins with proper folding and post-translational modifications. These systems are more suitable for expressing large proteins with functional and structural complexity.

5. Production Cost and Time:

• Smaller Proteins: Typically less expensive and faster to produce. Simple expression systems like bacteria can be used, reducing costs.
  
• Larger Proteins: More expensive and time-consuming to produce, especially if mammalian or insect cell systems are required. The need for complex folding and modification machinery increases production time and costs.
  

In summary, the molecular weight of a protein influences its expression yield, folding, solubility, post-translational modifications, suitability of expression systems, production cost and time, and purification challenges. Smaller proteins are generally easier to express and handle, while larger proteins require more sophisticated expression systems and processes to ensure proper folding, modifications, and functionality.

GenCefe provide one-stop solutions from codon optimization, gene synthesis, to protein expression and purification. In addition to four conventional expression systems of bacterial, yeast,insect cell, and mammalian cell, we have also developed a patented cell free expression technology, which is suitable for the production of difficult proteins such as toxic proteins and membrane proteins.