中文摘要：

为筛选新型水稻纹枯病菌GlmS活性抑制物质，采用3’RACE和5’RACE克隆了水稻纹枯病菌GImS的基因组DNA序列和完整的cDNA序列。GlmS基因组DNA序列全长2529bp，含有8个内含子；GImScDNA序列全长2094bp，推测编码一个含有697个氨基酸残基。分子量约为76．7kD的蛋白质。生物信息学分析表明水稻纹枯病菌GImS含有1个谷氨酰胺氨基转移酶结构域和2个葡萄糖异构酶结构域。采用大肠杆菌重组融合表达GImS，重组蛋白的分子量经过葡聚糖凝胶层析和SDS—PAGE电泳测得分别为306kD和77kD，表明GImS是由4个相同大小亚基组成的多聚酶复合体。重组蛋白的酶学性质研究表明其最适反应温度为37℃，最适pH为6．4，42℃下的半衰期为1h，在pH5．5～7．5时比较稳定。GImS催化反应能被己糖胺通路末端产物鸟苷氮乙酰葡萄糖胺反馈抑制。

英文摘要：

To develop novel antimicrobial agents to Rhizoctonia solani, the genomic gene and complete cDNA encoding glucosamine-6-phosphate synthetase were cloned and sequenced from the rice pathogen Rhizoctonia solani by 3CRACE and 5CRACE . Homologous to other reported GlmS in sequence, the GImS contains eight introns, and encodes a predicted protein of 697 amino acids. Domain structure analysis revealed that R. solani GlmS contained a glutamine transferase motif and two sugar isomerase motifs. Recombinant native R. solani GlmS enzyme was over-expressed using Escherichia coli and purified. The results of Gel filtration chromatography and SDS-PAGE revealed that it had an estimated molecular mass of 306 kD and consisted of four equal-sized subunits of 77 kD. The optimal reaction conditions for the recombinant GImS were pH 6.4 at 37°C, the half-life period for the recombinant GImS was 1 h at 42°C and the enzyme was stable at pH 5. 5-7. 5. R. solani GlmS activity was inhibited by the end-product of the hexosamine pathway, UDP-GlcNAc.