Isolation, expression and characterization of rbcL gene from Ulva prolifera J. Agardh (Ulvophyceae, Chlorophyta)

• Published in: Journal of Ocean University of China 2015-12, Vol.14 (6), p.1087-1095
• Main Authors: Shao, Zhanru, Li, Wei, Guo, Hui, Duan, Delin
• Format: Article
• Language: English
• Subjects: Algae; Amino acids; Aquatic plants; Carbon dioxide fixation; Chlorophyta; E coli; Earth and Environmental Science; Earth Sciences; Escherichia coli; Gene expression; Marine; Meteorology; Oceanography; Phaeophyta; Rhodophyta; Studies; Ulva; Ulvophyceae
• ISSN: 1672-5182; 1993-5021; 1672-5174
• DOI: 10.1007/s11802-015-2661-6

Ulva prolifera is a typical green alga in subtidal areas and can grow tremendously fast. A highly efficient Rubisco enzyme which is encoded by UpRbcL gene may contribute to the rapid growth. In this study, the full-length UpRbcL open reading frame (ORF) was identified, which encoded a protein of 474 amino acids. Phylogenetic analysis of UpRbcL sequences revealed that Chlorophyta had a closer genetic relationship with higher plants than with Rhodophyta and Phaeophyta. The two distinct residues (aa11 and aa91) were presumed to be unique for Rubisco catalytic activity. The predicted three-dimensional structure showed that one α/β-barrel existed in the C-terminal region, and the sites for Mg 2+ coordination and CO 2 fixation were also located in this region. Gene expression profile indicated that UpRbcL was expressed at a higher level under light exposure than in darkness. When the culture temperature reached 35°C, the expression level of UpRbcL was 2.5-fold lower than at 15°C, and the carboxylase activity exhibited 13.8-fold decrease. UpRbcL was heterologously expressed in E. coli and was purified by Ni 2+ affinity chromatography. The physiological and biochemical characterization of recombinant Rubisco will be explored in the future.