变形假单胞菌PtxS蛋白基因的克隆与分析

Cloning and Bioinformatics Analysis of the PtxS Gene from Pseudomonas plecoglossicida

为从变形假单胞菌中克隆2-酮基葡萄糖酸代谢调控蛋白Ptx S的基因,并明确其基本的生物学信息,采用同源比对的方法设计引物,利用TD-PCR技术克隆Ptx S的基因,再用生物信息学方法对其进行分析。试验结果表明:克隆的基因片段全长1 023 bp,其序列与铜绿假单胞菌、恶臭假单胞菌等假单胞菌的转录调控蛋白Ptx S的基因序列一致性达80%左右,编码由340个氨基酸残基组成的蛋白Ptx S。该蛋白与恶臭假单胞菌Ptx S的同源性最高,氨基酸序列一致性达88%。该蛋白定位于细胞质,无信号肽和跨膜区,为亲水性蛋白。该蛋白的氨基酸序列中含有多个结构域,其二级结构中α螺旋、延伸链、β转角和无规卷曲所占的比例分别为54.41%,13.53%,10.88%和21.18%。本研究为该基因的表达及表达产物的分离纯化提供了理论基础。

To clone the gene encoding 2-ketogluconate metabolic regulatory protein PtxS from Pseudomonas plecoglossicida JUIM01, and to investigate its biological information. The primers were designed by the homologous comparison, and the PtxS gene was amplified by TD-PCR. The gene was analyzed and the structures and functions of the PtxS were predicted by the bioinformatic methods. The gene sequence of ptx S revealed a complete open reading frame（ORF） of 1023 bp encoding 340 amino acid residues, and shared about 80% sequence identity with the gene of transcription regulatory protein PtxS from other pseudomonads such as Ps. aeruginosa, Ps. putida etc. The protein was predicted to be very high homologous to the PtxS from Ps. putida and share more than 80% sequence identity. This protein was located in the cytoplasm, without transmembrane domain and signal peptide, and was a hydrophilic protein. This protein had some domains and the predicted secondary structure contained 54.41% of α helixes, 13.53% of extended strand, 10.88% of β turns and 21.18% of random coil. The results of this study may provide a stable foundation for the expression and purification of PtxS protein.