Antibacterial Target DXP Synthase Catalyzes the Cleavage of d-Xylulose 5-Phosphate: a Study of Ketose Phosphate Binding and Ketol Transfer Reaction.
Antibacterial Target DXP Synthase Catalyzes the Cleavage of d-Xylulose 5-Phosphate: a Study of Ketose Phosphate Binding and Ketol Transfer Reaction.
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DOI：
10.1021/acs.biochem.2c00274
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发表时间：
2022-09-06
期刊：
影响因子：
2.9
通讯作者：
Meyers, Caren L. Freel
中科院分区：
文献类型：
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作者：
Johnston, Melanie L.;Bonett, Eucolona M.;DeColli, Alicia A.;Meyers, Caren L. Freel
细菌酶1-脱氧-d-木糖-5-磷酸合成酶(DXPs)催化丙酮酸和d-甘油醛-3-磷酸(d-GAP)以一种依赖于硫胺素二磷酸(ThDP)的方式合成DXP。除了在类异戊二烯生物合成中的作用外，DXP还是ThDP和吡哆醛磷酸生物合成所必需的。由于它作为支点酶的功能以及它所展示的底物和催化混杂，我们假设DXPs可能是细菌在感染过程中动态代谢格局中适应的关键。Freel Meyers实验室先前的工作表明，DXPs对供体和受体底物表现出松弛的特异性，并根据所用供体的不同而改变受体特异性。我们已经报道了DXPS分别由酮酸或醛供体底物通过脱羧基和去质子化生成二羟乙基(DHE)THDP。在这里，我们测试了其他DHE供体，发现DXP在C2-C3处裂解D-木糖5-磷酸(X5P)，通过第三种涉及d-间隙消除的机制产生DHEThDP。我们以X5P为供体底物考察了DXPS催化的反应，说明了(1)半稳定的酶结合中间体的产生，以及(2)O2、H+和d-红宝石4-磷酸作为受体底物，突出了DXPS新的转酮醇酶样活性。此外，我们研究了X5P与DXP的结合，并表明d-GAP结合口袋在X5P结合和周转中起着至关重要的作用。总体而言，这项研究揭示了DXPs催化的酮糖裂解反应，与其他C-C键形成酶相比，DXPs对供体底物的使用具有显著的灵活性。
The bacterial enzyme 1-deoxy-d-xylulose 5-phosphate synthase (DXPS) catalyzes the formation of DXP from pyruvate and d-glyceraldehyde 3-phosphate (d-GAP) in a thiamin diphosphate (ThDP)-dependent manner. In addition to its role in isoprenoid biosynthesis, DXP is required for ThDP and pyridoxal phosphate biosynthesis. Due to its function as a branch-point enzyme and its demonstrated substrate and catalytic promiscuity, we hypothesize DXPS could be key for bacterial adaptation in the dynamic metabolic landscape during infection. Prior work in the Freel Meyers lab has illustrated DXPS displays relaxed specificity toward donor and acceptor substrates and varies acceptor specificity according to the donor used. We have reported DXPS forms dihydroxyethyl (DHE)ThDP from ketoacid or aldehyde donor substrates via decarboxylation and deprotonation, respectively. Here, we tested other DHE donors and found DXPS cleaves d-xylulose 5-phosphate (X5P) at C2-C3, producing DHEThDP through a third mechanism involving d-GAP elimination. We interrogated DXPS–catalyzed reactions using X5P as a donor substrate and illustrated (1) production of a semi-stable enzyme-bound intermediate, and (2) O2, H+, and d-erythrose 4-phosphate act as acceptor substrates, highlighting a new transketolase-like activity of DXPS. Further, we examined X5P-binding to DXPS and suggest the d-GAP binding pocket plays a crucial role in X5P binding and turnover. Overall, this study reveals a ketose-cleavage reaction catalyzed by DXPS, highlighting the remarkable flexibility for donor substrate usage by DXPS compared to other C-C bond forming enzymes.
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影响因子：
6.4
作者：
Gruchattka E;Hädicke O;Klamt S;Schütz V;Kayser O
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影响因子：
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