a cost-effective elp-intein coupling system for recombinant protein purification from plant production platform具有成本效益的elp-intein耦合系统的重组蛋白纯化植物生产平台.pdfVIP

A Cost-Effective ELP-Intein Coupling System for Recombinant Protein Purification from Plant Production Platform Li Tian1,2,3, Samuel S. M. Sun2,3* 1 School of Life Sciences, Tsinghua University, Beijing, China, 2 Life Science Division, Graduate School at Shenzhen, Tsinghua University, Shenzhen, China, 3 School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China Abstract Background: Plant bioreactor offers an efficient and economical system for large-scale production of recombinant proteins. However, high cost and difficulty in scaling-up of downstream purification of the target protein, particularly the common involvement of affinity chromatography and protease in the purification process, has hampered its industrial scale application, therefore a cost-effective and easily scale-up purification method is highly desirable for further development of plant bioreactor. Methodology/Principal Findings: To tackle this problem, we investigated the ELP-intein coupling system for purification of recombinant proteins expressed in transgenic plants using a plant lectin (PAL) with anti-tumor bioactivity as example target protein and rice seeds as production platform. Results showed that ELP-intein-PAL (EiP) fusion protein formed novel irregular ER-derived protein bodies in endosperm cells by retention of endogenous prolamins. The fusion protein was partially self-cleaved in vivo, but only self-cleaved PAL protein was detected in total seed protein sample and deposited in protein storage vacuoles (PSV). The in vivo uncleaved EiP protein was accumulated up to 2–4.2% of the total seed protein. The target PAL protein could be purified by the ELP-intein system efficiently without using complicated instruments and expensive chemicals, and the yield of pure PAL protein by the current method was up