Structural adaptation of the plant protease Deg1 to repair photosystem II during light exposure

Deg1 is an HtrA protease that participates in the turnover of the photosynthetic proteins in chloroplasts. Now the crystal structure of Deg1, along with functional work, reveals that Deg1 oligomerization and activation occur in response to acidic pH, which should be encountered in the thylakoid lumen when exposed to light.