Improving Potato Protein's Heat Resistance

Greg Howard
15th July, 2025

Improving Potato Protein's Heat Resistance
Potato (Solanum tuberosum)

Key Findings

  • Researchers at the Swedish University of Agriculture successfully used gene editing to modify over 10% of targeted patatin genes in potatoes
  • Although these modified patatins didn't improve heat stability, one variant proved less sensitive to pH changes, a key benefit for industrial use
Patatins are a group of proteins found in potatoes, recognized for their high nutritional value and useful properties, making them attractive for industrial applications. However, a significant challenge in processing patatins is their low thermostability, meaning they easily lose their functional structure when heated, particularly in acidic conditions. This instability leads to aggregation, where proteins clump together, making purification difficult and limiting their use in food and other industries. To overcome this, scientists are exploring ways to stabilize the patatin protein structure, for instance, by introducing specific changes, known as point mutations, into their genetic code. Recent research from the Swedish University of Agriculture[1] has investigated this problem by exploring gene editing as a method to improve patatin stability. The study focused on the patatin gene cluster, a group of related genes responsible for producing these proteins in potato tubers. They found that only a few genes within this large family are primarily responsible for producing patatins in the potato tuber, and surprisingly, most of these dominant genes were predicted to be inactive in terms of their enzymatic function. The researchers then evaluated the effectiveness of using CRISPR/Cas9, a widely known gene-editing tool, to introduce changes into these patatin genes. CRISPR/Cas9 works by using a "guide RNA" molecule to direct a Cas9 enzyme to a specific DNA sequence, where it can then make a precise cut. The cell's natural repair mechanisms can then be harnessed to introduce desired changes. In this study, a single guide RNA sequence was used to target the patatin gene cluster, and the results showed that this approach could successfully introduce mutations in over 10% of all targeted gene copies, or "alleles," in the modified potatoes. This demonstrates the potential of gene editing for modifying these important plant proteins. To understand how these genetic changes might affect the patatin protein, the researchers designed four different patatin variants with specific amino acid substitutions. Amino acids are the building blocks of proteins, and changing even one can significantly alter a protein's structure and function. These designs were based on computer-aided analysis of the patatin protein's predicted three-dimensional structure. Once designed, these modified patatins were produced in bacteria for testing. The primary goal was to see if these engineered patatins had increased thermostability. Previous research on patatin aggregation[2] has shown that these proteins tend to aggregate even at relatively low temperatures, often before they are fully unfolded. This study also highlighted that changes in pH, or acidity, significantly impact patatin aggregation, with more acidic conditions leading to larger aggregates due to reduced electrostatic repulsion between protein molecules. Despite the careful design, none of the initial mutant patatin proteins from the Swedish University of Agriculture study showed improved overall thermostability compared to the natural, or "wild-type," patatin. This outcome underscores the complexity of protein engineering; predicting how a single amino acid change will affect a protein's overall stability is challenging. For instance, in an earlier study on T4 lysozyme[3], a single amino acid change from Serine to Phenylalanine at position 117 unexpectedly increased the protein's thermostability by a significant amount. This change involved a major reorientation of the new amino acid, burying it within the protein's core and forming new stabilizing interactions, even though it meant losing a hydrogen bond present in the original protein. This example from T4 lysozyme[3] shows that even large structural rearrangements can sometimes lead to increased stability, but it’s not always a straightforward prediction. While the primary goal of increased thermostability was not met in these initial variants, one of the engineered patatin candidates from the Swedish University of Agriculture study proved to be less sensitive to shifts in pH. This is a significant finding, as the pH sensitivity of patatins is a known challenge in their industrial processing, as detailed in the earlier aggregation study[2]. A protein that maintains its properties better across different pH levels would be much more versatile and easier to handle during extraction and purification. This pH-insensitive variant is therefore considered a promising candidate for further optimization efforts. The field of gene editing continues to advance rapidly. While the current study successfully used CRISPR/Cas9 to introduce mutations, newer techniques like prime editing[4] have emerged, offering even more precise control over genetic modifications. Prime editing allows for targeted insertions, deletions, and all 12 types of point mutations without requiring double-strand breaks in the DNA or external donor DNA templates, which can lead to fewer unintended changes or "byproducts." Such advancements in genome editing technology could potentially enable even more refined and precise modifications to proteins like patatin in future research, potentially leading to the desired improvements in thermostability or other functional properties with higher efficiency and fewer off-target effects. This ongoing research highlights the iterative nature of scientific discovery, where initial findings, even if not fully achieving the ultimate goal, pave the way for future improvements and deeper understanding.

BiotechBiochemPlant Science

References

Main Study

1) Modifying the potato tuber storage protein patatin targeting improved thermal stability

Published 11th July, 2025

https://doi.org/10.1007/s00425-025-04766-2

Related Studies

2) Heat-induced aggregation kinetics of potato protein - Investigated by chromatography, calorimetry, and light scattering.

https://doi.org/10.1016/j.foodchem.2022.133114

3) Hydrophobic core repacking and aromatic-aromatic interaction in the thermostable mutant of T4 lysozyme Ser 117-->Phe.

Journal: Protein science : a publication of the Protein Society, Issue: Vol 2, Issue 8, Aug 1993

4) Search-and-replace genome editing without double-strand breaks or donor DNA.

https://doi.org/10.1038/s41586-019-1711-4


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