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*Corresponding author e-mail: Kenro Oshima (kenro@hosei.ac.jp)
Since phytoplasma resides intracellularly within a host plant cell and lacks a cell wall, its membrane proteins may have important roles in the host-phytoplasma interaction. DegQ-like protein of onion yellows phytoplasma (OY-DegQ) is a membrane protein that contains a Deg/HtrA family serine protease domain and shows partial similarity to Escherichia coli DegQ. To examine the protease activity of OY-DegQ, the soluble domain of OY-DegQ was purified with glutathione S-trans- ferase and its function was analyzed. As a result, the degradation of a substrate protein was observed, suggesting that OY-DegQ functions as a protease.
Phytoplasma, Serine protease, Enzymatic activity, Plant disease