Nuclease activity of the recombinant plancitoxin-1-like proteins with mutations in the active site from Trichinella spiralis.

Chengshui Liao; Xiaoli Wang; Wenjing Tian; Mengke Zhang; Chunjie Zhang; Yinju LI; Tingcai WU; Xiangchao Cheng

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Nuclease activity of the recombinant plancitoxin-1-like proteins with mutations in the active site from Trichinella spiralis.

Author: Chengshui LIAO ¹ ; Xiaoli WANG ² ; Wenjing TIAN ¹ ; Mengke ZHANG ¹ ; Chunjie ZHANG ¹ ; Yinju LI ¹ ; Tingcai WU ¹ ; Xiangchao CHENG ¹
Author Information

1. Luoyang Key Laboratory of Live Carrier Biomaterial and Animal Disease Prevention and Control, College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471023, Henan, China.
2. Medical College, Henan University of Science and Technology, Luoyang 471023, Henan, China.
Publication Type:Journal Article
Keywords: Trichinella spiralis; active site; mutation; nuclease; plancitoxin-1-like
From: Chinese Journal of Biotechnology 2017;33(8):1315-1324
CountryChina
Language:Chinese
Abstract: Although there are 125 predicted DNase Ⅱ-like family genes in the Trichinella spiralis genome, plancitoxin-1-like (Ts-Pt) contains the HKD motif, a typical conserved region of DNase Ⅱ, in N- and C-terminal. It is generally believed that histidine is the active site in DNase Ⅱ. To study the nuclease activity of recombinant Ts-Pt with mutations in the active site from T. spiralis, different fragments of the mutated Ts-Pt genes were cloned using overlap PCR technique and inserted into the expressing vector pET-28a(+), and transformed into Escherichia coli Rosseta (DE3). The fusion proteins were purified by Ni-NTA affinity chromatography and SDS-PAGE. Nuclease activity of the recombinant proteins was detected by agarose gel electrophoresis and nuclease-zymography. The recombinant plasmids harboring the mutated Ts-Pt genes were constructed and expressed as inclusive body in a prokaryotic expression system. After renaturation in vitro, the recombinant proteins had no nuclease activity according to agarose gel electrophoresis. However, the expressed proteins as inclusive body displayed the ability to degrade DNA after renaturation in gel. And the nuclease activity was not affected after subjected to mutation of active site in N- and C-termini of Ts-Pt. These results provide the basis to study the relationship between DNase Ⅱ-like protein family and infection of T. spiralis.