by Adam Clore, Director of Development & Innovation, Integrated DNA Technologies
Site Directed Mutagenesis (SDM) is an invaluable tool that allows scientists to alter many characteristics of proteins. The method, however, introduces several challenges. In most cases, changing the function of a protein cannot be precisely determined a priori, often necessitating that a large number of mutants be generated and screened to find one containing the desired traits. Performing SDM across many sites is often complicated due to the secondary structure of DNA. Not all sites are created equal, particularly if they’re highly structured, have a lot of repeat sequences or have extremes in guanine-cytosine (GC) content.
To overcome these inherent challenges, it’s important to consider the appropriate scale of the experimental design to ensure enough variation is present to find the desired trait while minimizing the time and cost in creation and screening of mutant libraries. While there are some decent predictive models, particularly for well characterized proteins like antibodies, they are not 100% accurate, so finding the desired mutant often involves large libraries or iterative rounds of mutagenesis and screening depending on the size of the protein and the resources available in the lab.
Read more on Labcompare.