Crop Biotech Update

Plant Enzyme Could Guide Development of Medicines and Other Products

September 11, 2019
The protein X-ray crystal structure of chalcone isomerase, complexed with a product molecule called (2S)-naringenin, reveals how the active site arginine (labeled as Arg 37) facilitates catalysis of the correct isomer. Photo Source: Salk Institute/ACS Catalysis

Plants manufacture compounds to help them repel pests, attract pollinators, cure infections and protect themselves from excess temperatures, drought, and other hazards in the environment. Salk Institute researchers who are studying how plants evolved the abilities to make these natural chemicals have now uncovered how an enzyme called chalcone isomerase evolved to enable plants to make products that are important to their survival. The researchers hope that this knowledge facilitates the manufacturing of products that are beneficial to humans, including medications and improved crops.

Chalcone isomerase acts as a catalyst to accelerate plant chemical reactions. It also helps ensure that chemicals made in the plant are in proper form since molecules with the same chemical formula can take two different variations that are mirror images of each other (called isomers). The researchers identified the part of chalcone isomerase's structure that allowed it to catalyze reactions incredibly fast while also ensuring it makes the proper, biologically active isomer. These reactions lead to a host of activities in plants, including converting primary metabolites like phenylalanine and tyrosine into vital specialized molecules called flavonoids.

The researchers found that the amino acid arginine, one of many amino acids linked together in chalcone isomerase sat in a location, shaped by evolution, that allowed it to play the key role in how chalcone isomerase reactions were catalyzed. The researchers said that their new understanding of chalcone isomerase enables them to design molecular systems that can carry out a particular task even in the next generation of nutritionally dense crops capable of transforming the greenhouse gas carbon dioxide into molecules essential for life.

For more details, read the article in Salk News.

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