3-Phosphoglycerate is an allosteric activator of pyruvate kinase from the hyperthermophilic archaeon Pyrobaculum aerophilum.
3-Phosphoglycerate is an allosteric activator of pyruvate kinase from the hyperthermophilic archaeon Pyrobaculum aerophilum.
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3-Phosphoglycerate 是来自嗜热古细菌 Pyrobaculum aerophilum 的丙酮酸激酶的变构激活剂。
DOI：
10.1021/bi400761b
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发表时间：
2013
期刊：
影响因子：
2.9
通讯作者：
Davies,Christopher
中科院分区：
文献类型：
--
作者：
Solomons,JTGraham;Johnsen,Ulrike;Schönheit,Peter;Davies,Christopher
丙酮酸激酶（PK）是一种高度调控的酶，催化糖酵解的最后一步。嗜热古嗜热菌（PaPK）的PK酶与真核生物和细菌的PK酶不同，它不响应任何已知的变构效应物，显然只表现出合作调节。我们以2.2 Å分辨率确定了papk的晶体结构，并且以一种与缺乏对传统效应物响应的方式一致，观察到典型变构位点被酪氨酸遮挡。然而，出乎意料的是，在相当于糖效应物的6 ' -磷酸的位置上观察到一个结合的硫酸盐，这表明一个变构位点，但对于未知的效应物，只共享磷酸盐位置。对糖酵解的三碳中间体的研究表明，3-磷酸甘油酸（3PG）是一种有效的papk变构活化剂。这种反应被与硫酸盐接触的残基和与3PG羧酸基相互作用的精氨酸的突变所消除。3PG对PK的调节与嗜热古菌的祖先糖酵解一致，其中这种中间体是由一种不可逆酶甘油醛3-磷酸铁氧化还蛋白氧化还原酶产生的。糖酵解下半部分的协调调节与传统糖酵解形成鲜明对比，在传统糖酵解中，3PG是可逆产生的，而PK是由果糖1,6-二磷酸调节的，果糖1,6-二磷酸是磷酸果糖激酶的产物，是该途径上半部分的一种不可逆酶。羧酸盐分子而不是糖磷酸分子对papk的调节可能反映了糖酵解进化的一个步骤，这个步骤早于糖在代谢中的主导地位。
Pyruvate kinase (PK) is a highly regulated enzyme that catalyzes the final step of glycolysis. PK from the hyperthermophilic archaeonPyrobaculum aerophilum(PaPK) is distinguished from most PK enzymes of eukarya and bacteria by not responding to any known allosteric effectors and apparently exhibiting only cooperative regulation. We determined the crystal structure ofPaPK to 2.2 Å resolution and, in a manner consistent with the lack of a response to conventional effectors, observed that the canonical allosteric site is occluded by a tyrosine. Unexpectedly, though, a bound sulfate was observed at a position equivalent to the 6′-phosphate of sugar effectors, suggesting an allosteric site, but for an unknown effector and sharing only the phosphate position. A search of three-carbon intermediates of glycolysis revealed 3-phosphoglycerate (3PG) as a potent allosteric activator ofPaPK. The response was abolished by mutation of residues that contact the sulfate and of an arginine proposed to interact with the 3PG carboxylate group. Regulation of PK by 3PG is consistent with the ancestral glycolysis of hyperthermophilic archaea in which this intermediate is produced by an irreversible enzyme, glyceraldehyde 3-phosphate ferredoxin oxidoreductase. Coordinated regulation within the lower half of glycolysis contrasts sharply with conventional glycolysis in which 3PG is produced reversibly and PK is regulated by fructose 1,6-bisphosphate, the product of phosphofructokinase, an irreversible enzyme in the upper half of the pathway. Regulation ofPaPK by a carboxylate molecule rather than a sugar phosphate may reflect a step in the evolution of glycolysis that predates the dominance of sugars in metabolism.