Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8352855 | Plant Physiology and Biochemistry | 2018 | 28 Pages |
Abstract
In this study, two pathogenesis-related (PR) class 10 protein isoforms, ASPR-1 and ASPR-2, were purified from fresh roots of the Chinese medicinal plant Angelica sinensis (A. sinensis) using 80% ammonium sulfate precipitation, Sephadex G50 gel filtration chromatography, and DEAE-Sepharose ion-exchange chromatography. The molecular masses of ASPR-1 and ASPR-2 were estimated to be 16.66â¯kDa and 16.46â¯kDa, respectively, using sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The isoforms are both glycoproteins containing glycosyl contents of 1.8% (ASPR-1) and 3.4% (ASPR-2). The two isoforms were predominantly present as monomers, but they partially dimerized in solution. The 15â¯N-terminal amino acids of ASPR-1 were determined to be GIQKTEVEAPSTVSA, with significant sequence homology to certain PR-10 proteins. ASPR-2 was also identified using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS) analysis to be a PR-10 protein. The isoforms both exhibited ribonuclease (RNase) activity, with ASPR-2 having higher specific activity (128.85 U mgâ1) than ASPR-1 (68.67 U mgâ1). The isoforms had the same optimal temperature of 50â¯Â°C but different optimal pH values of 5.0 (ASPR-1) and 6.0 (ASPR-2). The RNase activities of the isoforms were both stable for 30â¯minâ¯at 50â¯Â°C, rapidly decreasing at higher or lower processing temperatures. However, ASPR-1 retained higher residual activity (89.4%-80.9%) than ASPR-2 (74.3%-67.9%) at temperatures from 40â¯Â°C to 60â¯Â°C. These results provide additional information to enrich the current knowledge of poorly annotated A. sinensis proteins.
Keywords
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Agricultural and Biological Sciences
Plant Science
Authors
Jianru Pan, Xiangling Wang, Lingling Li, Xian Li, Xiaoqiang Ye, Di Lv, Cuihuang Chen, Shutao Liu, Huocong He,