LOSS OF PROTEIN KINASE-CATALYZED PHOSPHORYLATION OF HPR, A PHOSPHOCARRIER PROTEIN OF THE PHOSPHOTRANSFERASE SYSTEM, BY MUTATION OF THE PTSH GENE CONFERS CATABOLITE REPRESSION RESISTANCE TO SEVERAL CATABOLIC GENES OF BACILLUS-SUBTILIS
LOSS OF PROTEIN KINASE-CATALYZED PHOSPHORYLATION OF HPR, A PHOSPHOCARRIER PROTEIN OF THE PHOSPHOTRANSFERASE SYSTEM, BY MUTATION OF THE PTSH GENE CONFERS CATABOLITE REPRESSION RESISTANCE TO SEVERAL CATABOLIC GENES OF BACILLUS-SUBTILIS
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DOI：
10.1128/jb.176.11.3336-3344.1994
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发表时间：
1994-06-01
影响因子：
3.2
通讯作者：
STEINMETZ, M
中科院分区：
文献类型：
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作者：
DEUTSCHER, J;REIZER, J;STEINMETZ, M
在革兰氏阳性菌中，HPr（磷酸烯醇丙酮酸：糖磷酸转移酶系统 (PTS) 的磷酸载体蛋白）被丝氨酰残基 46 上的 ATP 依赖性代谢物激活蛋白激酶磷酸化。在枯草芽孢杆菌突变株中，其中 HPr 的 Ser-46 被不可磷酸化的丙氨酰残基（ptsH1 突变）取代，合成葡萄糖酸激酶、葡萄糖醇脱氢酶、甘露醇-1-P脱氢酶和甘露醇特异性PTS通透酶完全解除了葡萄糖、果糖或甘露醇的抑制，而肌醇脱氢酶的合成部分解除了分解代谢物的抑制，并且α-葡萄糖苷酶和甘油激酶的合成仍然受到分解代谢物的抑制。当 HPr 中的 S46A 突变恢复为 S46 野生型 HPr 时，葡萄糖酸激酶和葡萄糖醇脱氢酶的表达恢复了对 PTS 糖的抑制的完全敏感性。这些结果表明 HPr Ser-46 处的磷酸化直接或间接参与分解代谢物抑制。用表达野生型ptsH基因或各种S46突变体ptsH基因（S46A或S46D）的质粒转化ptsGHI基因缺失的菌株。根据核磁共振数据，编码S46D HPr的基因与P-ser-HPr的结构相似，其表达导致葡萄糖酸激酶活性显着降低，而编码uild型或S46A HPr的基因的表达对此酶活性没有影响。当无启动子的lacZ基因被置于肠道启动子的控制下并随后被整合到枯草芽孢杆菌染色体上的amyE基因中时，β-半乳糖苷酶的表达被葡萄糖酸诱导并被葡萄糖抑制。然而，我们在携带 ptsH1 突变的菌株中观察到 β-半乳糖苷酶活性没有受到抑制。此外，我们研究了 ccpA 突变株，并观察到我们发现在 ptsH1 突变株中从碳分解代谢物抑制中缓解的所有酶也对 ccpA 突变体中的分解代谢物抑制不敏感。在 ptsH1 突变体中被抑制的酶在 ccpA 突变体中也被抑制。
In gram-positive bacteria, HPr, a phosphocarrier protein of the phosphoenolpyruvate:sugar phosphotransferase system (PTS), is phosphorylated by an ATP-dependent, metabolite-activated protein kinase on seryl residue 46. In a Bacillus subtilis mutant strain in which Ser-46 of HPr was replaced with a nonphosphorylatable alanyl residue (ptsH1 mutation), synthesis of gluconate kinase, glucitol dehydrogenase, mannitol-1-P dehydrogenase and the mannitol-specific PTS permease was completely relieved from repression by glucose, fructose, or mannitol, whereas synthesis of inositol dehydrogenase was partially relieved from catabolite repression and synthesis of alpha-glucosidase and glycerol kinase was still subject to catabolite repression. When the S46A mutation in HPr was reverted to give S46 wild-type HPr, expression of gluconate kinase and glucitol dehydrogenase regained full sensitivity to repression by PTS sugars. These results suggest that phosphorylation of HPr at Ser-46 is directly or indirectly involved in catabolite repression. A strain deleted for the ptsGHI genes was transformed with plasmids expressing either the wild-type ptsH gene or various S46 mutant ptsH genes (S46A or S46D). Expression of the gene encoding S46D HPr, having a structure similar to that of P-ser-HPr according to nuclear magnetic resonance data, caused significant reduction of gluconate kinase activity, whereas expression of the genes encoding uild-type or S46A HPr had no effect on this enzyme activity. When the promoterless lacZ gene was put under the control of the gut promoter and was subsequently incorporated into the amyE gene on the B. subtilis chromosome, expression of beta-galactosidase was inducible by gluconate and repressed by glucose. However, we observed no repression of beta-galactosidase activity in a strain carrying the ptsH1 mutation. Additionally, we investigated a ccpA mutant strain and observed that all of the enzymes which we found to be relieved from carbon catabolite repression in the ptsH1 mutant strain were also insensitive to catabolite repression in the ccpA mutant. Enzymes that were repressed in the ptsH1 mutant were also repressed in the ccpA mutant.