Liya Ma1,2, Wen Wang1,2, Chaozhi Hao3, Li Zheng2, Ling Wang1, Minggang Zheng4. 1. Environmental Science and Engineering, Qingdao University, Qingdao, 266071, China. 2. Marine Bioresources and Environment Research Center, First Institute of Oceanography, Ministry of Natural Resources, 6 XianXiaLing Road, Qingdao, Shandong, China. 3. Institute of Environmental Biotechnology and Functional Materials, School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, China. 4. Marine Bioresources and Environment Research Center, First Institute of Oceanography, Ministry of Natural Resources, 6 XianXiaLing Road, Qingdao, Shandong, China. 1565501835@qq.com.
Abstract
BACKGROUND: All RecJ proteins are known to date only perform exonuclease activity. The present study reports that a novel RecJ protein obtained from Bacillus cereus isolated from marine sediments has both endonuclease and exonuclease activities. METHODS: Analysis of the BcRecJ expression induction in E. coli BL21 revealed that the BcRecJ protein cleaved plasmids and genomic DNA in the host cell, and led to cell death and decreased the DNA content. Further, the BcRecJ protein had the ability to degrade supercoiled plasmid DNA into circular or linear forms in vitro. Meanwhile, the BcRecJ protein loaded with an S-modified guide facilitated plasmid linearization and reduced smear formation. RESULTS: The results suggested that this novel BcRecJ protein was different from any reported RecJs and had a longer C-terminus. Testing the BcRecJ mutants indicated that the endonuclease activity was affected by two residues of BcRecJ (D561, E637) after testing the BcRecJ mutants. CONCLUSION: The discovery of the type of protein is a new breakthrough for the RecJ proteins, which has both endonuclease and exonuclease activities.
BACKGROUND: All RecJ proteins are known to date only perform exonuclease activity. The present study reports that a novel RecJ protein obtained from Bacillus cereus isolated from marine sediments has both endonuclease and exonuclease activities. METHODS: Analysis of the BcRecJ expression induction in E. coli BL21 revealed that the BcRecJ protein cleaved plasmids and genomic DNA in the host cell, and led to cell death and decreased the DNA content. Further, the BcRecJ protein had the ability to degrade supercoiled plasmid DNA into circular or linear forms in vitro. Meanwhile, the BcRecJ protein loaded with an S-modified guide facilitated plasmid linearization and reduced smear formation. RESULTS: The results suggested that this novel BcRecJ protein was different from any reported RecJs and had a longer C-terminus. Testing the BcRecJ mutants indicated that the endonuclease activity was affected by two residues of BcRecJ (D561, E637) after testing the BcRecJ mutants. CONCLUSION: The discovery of the type of protein is a new breakthrough for the RecJ proteins, which has both endonuclease and exonuclease activities.