Yu Gao, Hong-mei Zhang, Pi-wu Wang* and Mei Li* Pages 528 - 533 ( 6 )
Background: Peptidyl-prolyl cis-trans isomerase (PPIase) accelerates the intrinsically slow conversion between cis- and trans- configurations of proline, thus affecting backbone conformation and altering the direction of peptide chains. PPIase from Pseudomonas syringae pv. Tomato (PSPTO) DC3000 (PSPTO-PPIase) is considered to belong to the FKBP subfamily of PPIase.Objective: To solve the high resolution structure of the PSPTO-PPIase, and to explore its potential function in plants pathogen PSPTO DC3000. Method: The PSPTO-PPIase was expressed in E.coli and purified through ion exchange and size exclusion chromatography. While only the C-terminal domain of PSPTO-PPIase was successfully crystalized, and its structure was solved to 1.6 Å resolution by molecular replacement method. Results: Structural comparison showed that PSPTO-PPIase adopts a similar overall fold with microphage infectivity potentiators (MIPs), which also belong to the FKBP subfamily of PPIase. In addition, the BIAcore result confirmed that PSPTO-PPIase can bind an immunosuppressive drug FK506 as some other FKBP subfamily members do. Conclusion: Our results suggested that PSPTO-PPIase may function in a similar manner to virulent factor MIPs during pathogenesis. And the immunosuppressive drugs FK506 and rapamycin binding to PSPTO-PPIase potentially interferes and inhibits the plant pathogen PSPTO DC3000. In addition, the amino acids with short side chains in the fourth loop (L4) of PSPTO-PPIase may account for its variable roles in the respective pathogen.
FKBP, PPIase, crystal structure, MIP, FK506, rapamycin.
College of Agronomy, Jilin Agricultural University, No.2888 Xincheng Street, Changchun, Jilin, National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, College of Agronomy, Jilin Agricultural University. No.2888 Xincheng Street, Changchun, Jilin, National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101