十字花科黑腐病菌中葡萄糖-6-磷酸脫氫酶的酶學分析
發(fā)布時間：2019-07-12 08:25
【摘要】：葡萄糖-6-磷酸脫氫酶是磷酸戊糖途徑(HMP)的限速酶,在十字花科黑腐病菌8004的基因組中,有2個基因XC1977和XC4082被注釋為葡萄糖-6-磷酸脫氫酶(G6PD)。前期工作發(fā)現(xiàn)XC1977突變后,細胞的胞外多糖產(chǎn)量明顯降低,而XC4082突變不影響胞外多糖產(chǎn)量。為明確這兩個基因的編碼產(chǎn)物在Xcc中的生化功能,本工作表達純化了這兩個蛋白,并對這兩個蛋白的特征進行分析,發(fā)現(xiàn)這兩個蛋白均具有6-葡萄糖脫氫酶的活性,但是它們的最適反應溫度、最適反應pH、金屬離子和烷化劑的敏感性完全不同。而且,XC1977以NAD~+和NADP~+為電子受體,而XC4082只能以NADP~+為電子受體。在以NAD~+和NADP~+為受體時,XC1977的K_m值分別為0.125 mmol/L和0.927 mmol/L,而XC4082以NADP~+為受體時的K_m值為0.364 mmol/L。這表明Xcc細胞合成胞外多糖時,需要NAD~+參與能量代謝。
[Abstract]:Glucose-6-phosphate dehydrogenase is the rate-limiting enzyme of pentose phosphate pathway (HMP). In the genome of Cruciferae black rot fungus 8004, two genes XC1977 and XC4082 are annotated as glucose-6-phosphate dehydrogenase (G6PD). It was found that the extracellular polysaccharide production decreased significantly after XC1977 mutation, but XC4082 mutation did not affect the extracellular polysaccharide yield. In order to clarify the biochemical function of the coding products of the two genes in Xcc, the two proteins were expressed and purified, and the characteristics of the two proteins were analyzed. It was found that the two proteins had the activity of 6-glucose dehydrogenase, but their optimum reaction temperature and sensitivity to pH, metal ions and alkylating agents were completely different. Moreover, XC1977 uses NAD~ and NADP~ as electron receptors, while XC4082 can only use NADP~ as electron receptors. When NAD~ and NADP~ were used as receptors, the km values of XC1977 were 0.125 mmol/L and 0.927 mmol/L, respectively, while the km values of XC4082 with NADP~ as receptors were 0.364 mmol/L.. This suggests that NAD~ is needed to participate in energy metabolism when Xcc cells synthesize extracellular polysaccharides.
【作者單位】： 廣西農(nóng)業(yè)科學院植物保護研究所;廣西作物病蟲害生物學重點實驗室;廣西大學生命科學與技術(shù)學院;廣西大學亞熱帶農(nóng)業(yè)生物資源保護利用國家重點實驗室;
【基金】：國家自然科學基金項目(31660506) 廣西自然科學基金(2015GXNSFBA139110) 廣西農(nóng)業(yè)科學院科技發(fā)展基金(桂農(nóng)科2016JZ07) 廣西科技計劃項目(桂科AD16380018)共同資助
【分類號】：S432.42
本文編號：2513581
[Abstract]:Glucose-6-phosphate dehydrogenase is the rate-limiting enzyme of pentose phosphate pathway (HMP). In the genome of Cruciferae black rot fungus 8004, two genes XC1977 and XC4082 are annotated as glucose-6-phosphate dehydrogenase (G6PD). It was found that the extracellular polysaccharide production decreased significantly after XC1977 mutation, but XC4082 mutation did not affect the extracellular polysaccharide yield. In order to clarify the biochemical function of the coding products of the two genes in Xcc, the two proteins were expressed and purified, and the characteristics of the two proteins were analyzed. It was found that the two proteins had the activity of 6-glucose dehydrogenase, but their optimum reaction temperature and sensitivity to pH, metal ions and alkylating agents were completely different. Moreover, XC1977 uses NAD~ and NADP~ as electron receptors, while XC4082 can only use NADP~ as electron receptors. When NAD~ and NADP~ were used as receptors, the km values of XC1977 were 0.125 mmol/L and 0.927 mmol/L, respectively, while the km values of XC4082 with NADP~ as receptors were 0.364 mmol/L.. This suggests that NAD~ is needed to participate in energy metabolism when Xcc cells synthesize extracellular polysaccharides.
【作者單位】： 廣西農(nóng)業(yè)科學院植物保護研究所;廣西作物病蟲害生物學重點實驗室;廣西大學生命科學與技術(shù)學院;廣西大學亞熱帶農(nóng)業(yè)生物資源保護利用國家重點實驗室;
【基金】：國家自然科學基金項目(31660506) 廣西自然科學基金(2015GXNSFBA139110) 廣西農(nóng)業(yè)科學院科技發(fā)展基金(桂農(nóng)科2016JZ07) 廣西科技計劃項目(桂科AD16380018)共同資助
【分類號】：S432.42
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