Structure of Plant Immunity Protein Revealed 25 Years After Discovery

NPR1 is a plant protein that plays a key role in protecting flowering plants against numerous pathogens. Discovered 25 years ago, scientists have finally gathered its structural data that is crucial in explaining how the protein works to govern plant protection on a molecular level.

Scientists used x-ray crystallography and Cryo-electron microscopy to obtain the protein's structure. These helped capture high resolution images of NPR1, revealing that two NPR1 proteins come together to form a bird-like shape. It is comprised of a central Broad-complex, Tramtrack and Bric-a-brac (BTB) domain, a BTB and carboxyterminal Kelch helix bundle, four ankyrin repeats and a disordered salicylic-acid-binding domain. At the tip of the "wings", NPR1 binds to molecules in the cell's nucleus to turn on plant immune genes.

Understanding how the protein works and interacts with other molecules encourages more research opportunities for enhancing disease resistance in plants. The new images can help researchers develop plants with high NPR1 levels that are better immune to pathogens without limiting plant growth rate, a common consequence of high NPR1 levels. Researchers would also like to find out how NPR1 folds into a new shape when an infection activates the protein's response.

The details of the study are published by Nature and reported by the Howard Hughes Medical Institute .