Chinese Journal of Rice Science

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Prokaryotic Expression of Polygalacturonase-Inhibiting Protein Gene (Ospgip1) from Rice and Bioinformatics Analysis of Its Coding Product

CHEN Xi-jun 1, 2, LIU Xiao-wei 1, ZUO Shi-min 2, TONG Yun-hui 1, PAN Xue-biao 2,*, XU Jing-you 1,*
  

  1. (1Horticulture and Plant Protection College, Yangzhou University, Yangzhou 225009, China; 2Key Laboratory of Plant Functional Genomics of Ministry of Education/Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Yangzhou University, Yangzhou 225009, China; *Corresponding author, E-mail: shuidao@yzu.edu.cn; jyxu@yzu.edu.cn)
  • Received:2010-06-26 Revised:2010-09-13 Online:2011-03-11 Published:2011-03-11

水稻多聚半乳糖醛酸酶抑制蛋白基因(Ospgip1)原核表达及编码产物生物信息学分析

陈夕军1, 2 ;刘晓维1;左示敏2;童蕴慧1;潘学彪2,*;徐敬友1,*
  

  1. (1扬州大学 园艺与植物保护学院, 江苏 扬州 225009; 2 扬州大学 江苏省作物遗传生理重点实验室/植物功能基因组学教育部重点实验室, 江苏 扬州 225009; *通讯联系人, E-mail: shuidao@yzu.edu.cn; jyxu@yzu.edu.cn)

Abstract: According to the sequences of GenBank and relative references, a fragment of 930 bp including the total open reading frame of Ospgip1 gene was amplified. Prokaryotic expression product of the gene could inhibit the growth and polygalacturonase (PG) activity of Rhizoctonia solani, the pathogen of rice sheath blight. Bioinformatics analysis showed that OsPGIP1 was a hydrophobic protein with a molecular weight of 32.8 kDa and a pI of 7.26. The protein was mainly located in the cell wall of rice, and the splice site of its signal peptide was between the 17th and 18th amino acid residue. There were four cysteines in the N- and C-terminal of the deduced amino acid sequence, respectively, forming three disulfide bonds (Between 56th and 63rd, 278th and 298th, 300th and 308th amino acid residue, respectively). The main structural elements of the deduced protein, which showed the typical leucine-rich repeat(LRR) modular organization, were α-helix, β-sheet and irregular circle. Comparing to PGIPs of other plants, the 7th LRR of this protein was absent. The nine LRRs could form a cleft which would be the activity site domain between the protein-protein interaction of the PGIP from rice and PG from the pathogenic fungi.

Key words: polygalacturonase-inhibiting protein, prokaryotic expression, bioinformatics analysis, rice sheath blight, rice

摘要: 据GenBank及相关文献提供的序列,从水稻基因组DNA中扩增出930 bp的Ospgip1基因完整开放阅读框。原核表达Ospgip1基因,表达产物能显著抑制水稻纹枯病菌菌丝生长及其多聚半乳糖醛酸酶活性。生物信息学分析表明,OsPGIP1为分子量32.8 kDa、pI 7.26的疏水蛋白,主要位于细胞壁(55.6%),信号肽切点位于第17和18位氨基酸之间。在N端和C端各有4个半胱氨酸残基,形成3个二硫键(第56和63位、第278和298位、第300和308位氨基酸)。以α-螺旋、β-折叠和不规则盘绕等为主要结构原件,具有典型的富含亮氨酸重复(LRR)结构。相比其他植物的PGIP,OsPGIP1缺少第7个LRR。在空间上9个LRR形成类似凹陷或裂隙结构,可能是其与病原菌多聚半乳糖醛酸酶互作的活性位点区。

关键词: 多聚半乳糖醛酸酶抑制蛋白, 原核表达, 生物信息学分析

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