NMP 激酶 AK3 中 GTP 与 ATP 选择性的结构基础。,Biochemistry

当前位置： X-MOL 学术 › Biochemistry › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

NMP 激酶 AK3 中 GTP 与 ATP 选择性的结构基础。
Biochemistry ( IF 2.9 ) Pub Date : 2020-08-21 , DOI: 10.1021/acs.biochem.0c00549
Per Rogne ₁ , Beata Dulko-Smith ₂ , Jack Goodman ₁ , Marie Rosselin ₁ , Christin Grundström ₁ , Christian Hedberg ₁ , Kwangho Nam ₂ , A Elisabeth Sauer-Eriksson ₁ , Magnus Wolf-Watz ₁

Affiliation

ATP 和 GTP 是生物学中极其重要的分子，具有多种且通常是离散的功能。因此，与它们中的任何一个结合的酶必须开发强大的机制来选择性地利用其中一个。在这里，这个特定的问题通过人类 NMP 激酶 AK3 的分子研究得到解决，该激酶使用 GTP 来磷酸化 AMP。AK3 在柠檬酸循环中起着重要作用，它负责 GTP/GDP 循环。通过将结构生物学方法与功能实验相结合，我们对酶的结构和机理有了全面的了解。我们发现 AK3 通过将 GTP 募集到活性位点而发挥作用，而 ATP 被拒绝并与 AMP 结合位点非生产性地结合。因此，ATP 作为 GTP 和 AMP 的抑制剂。对正确底物的特异性识别和不正确底物的非生产性结合的总体特征与先前对 ATP 特异性 NMP 激酶腺苷酸激酶的发现具有很强的相似性。总之，我们现在能够提供大型 NMP 激酶家族中 GTP 和 ATP 选择性的基本原理。作为源自 GTP 和 ATP 滴定中化学位移非线性的副作用，我们发现蛋白质表面对 GTP 和 ATP 提供了普遍而弱的结合亲和力。这些非特异性相互作用可能会降低可用的细胞内 GTP 和 ATP 浓度，并可能相应地驱动 NMP 激酶的 Michaelis 常数的进化。

"点击查看英文标题和摘要"

Structural Basis for GTP versus ATP Selectivity in the NMP Kinase AK3.

ATP and GTP are exceptionally important molecules in biology with multiple, and often discrete, functions. Therefore, enzymes that bind to either of them must develop robust mechanisms to selectively utilize one or the other. Here, this specific problem is addressed by molecular studies of the human NMP kinase AK3, which uses GTP to phosphorylate AMP. AK3 plays an important role in the citric acid cycle, where it is responsible for GTP/GDP recycling. By combining a structural biology approach with functional experiments, we present a comprehensive structural and mechanistic understanding of the enzyme. We discovered that AK3 functions by recruitment of GTP to the active site, while ATP is rejected and nonproductively bound to the AMP binding site. Consequently, ATP acts as an inhibitor with respect to GTP and AMP. The overall features with specific recognition of the correct substrate and nonproductive binding by the incorrect substrate bear a strong similarity to previous findings for the ATP specific NMP kinase adenylate kinase. Taken together, we are now able to provide the fundamental principles for GTP and ATP selectivity in the large NMP kinase family. As a side-result originating from nonlinearity of chemical shifts in GTP and ATP titrations, we find that protein surfaces offer a general and weak binding affinity for both GTP and ATP. These nonspecific interactions likely act to lower the available intracellular GTP and ATP concentrations and may have driven evolution of the Michaelis constants of NMP kinases accordingly.

更新日期：2020-09-29

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南