Catalytic mechanism and allosteric regulation of an oligomeric (p)ppGpp synthetase by an alarmone
Catalytic mechanism and allosteric regulation of an oligomeric (p)ppGpp synthetase by an alarmone
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警报酮对寡聚 (p)ppGpp 合成酶的催化机制和变构调节
DOI：
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发表时间：
2015
影响因子：
11.1
通讯作者：
G. Bange
中科院分区：
文献类型：
--
作者：
Wieland Steinchen;J. Schuhmacher;F. Altegoer;C. Fage;V. Srinivasan;U. Linne;M. Marahiel;G. Bange
鸟苷四磷酸（ppGpp）和鸟苷五磷酸（pppGpp）[统称为“（p）ppGpp "]对于细菌和植物叶绿体适应各种环境胁迫条件是重要的。它们的合成通过（p）ppGpp合成酶进行。我们描绘的催化机制（p）ppGpp合成寡聚和高度合作的小alarmone合成酶1（SAS 1）在原子分辨率。我们的结构和生化分析表明，只有pppGpp，而不是ppGpp，积极影响SAS 1的活动。据我们所知，这是pppGpp和ppGpp执行不同功能角色的生物活性的第一个分子描述。基于核苷酸的第二信使在生物体对环境变化的反应中起作用。在细菌和植物叶绿体中，鸟苷四磷酸（ppGpp）和鸟苷五磷酸（pppGpp）[统称为“（p）ppGpp”]充当在各种应激条件期间全局重编程细胞生理学的警报素。RelA/SpoT同源（RSH）家族的酶通过将焦磷酸从ATP转移到GDP或GTP来合成（p）ppGpp。目前对Alarmone合成的催化机制和调控机制知之甚少。也不清楚ppGpp和pppGpp是否执行不同的功能。在这里，我们解开的机制和变构调节的高度合作的小alarmone合成酶1（SAS 1）从枯草芽孢杆菌。我们确定，（p）ppGpp合成的催化途径涉及一个有序的底物结合，激活ATP的紧张构象，并通过亲核取代（SN 2）反应转移焦磷酸。我们发现，pppGpp，但不是ppGpp，积极调节SAS 1在变构网站。虽然生理意义仍有待阐明，我们建立的生物活性，其中ppGpp和pppGpp执行不同的功能角色的结构和机制的基础。
Significance The alarmones guanosine tetraphosphate (ppGpp) and guanosine pentaphosphate (pppGpp) [collectively named “(p)ppGpp)”] are important for the adaptation of bacteria and plant chloroplasts to a variety of environmental stress conditions. Their synthesis is carried out by (p)ppGpp synthetases. We delineate the catalytic mechanism of (p)ppGpp synthesis by oligomeric and highly cooperative small alarmone synthetase 1 (SAS1) at atomic resolution. Our structural and biochemical analysis shows that only pppGpp—but not ppGpp—positively affects the activity of SAS1. To our knowledge, this is the first molecular description of a biological activity in which pppGpp and ppGpp execute different functional roles. Nucleotide-based second messengers serve in the response of living organisms to environmental changes. In bacteria and plant chloroplasts, guanosine tetraphosphate (ppGpp) and guanosine pentaphosphate (pppGpp) [collectively named “(p)ppGpp”] act as alarmones that globally reprogram cellular physiology during various stress conditions. Enzymes of the RelA/SpoT homology (RSH) family synthesize (p)ppGpp by transferring pyrophosphate from ATP to GDP or GTP. Little is known about the catalytic mechanism and regulation of alarmone synthesis. It also is unclear whether ppGpp and pppGpp execute different functions. Here, we unravel the mechanism and allosteric regulation of the highly cooperative alarmone synthetase small alarmone synthetase 1 (SAS1) from Bacillus subtilis. We determine that the catalytic pathway of (p)ppGpp synthesis involves a sequentially ordered substrate binding, activation of ATP in a strained conformation, and transfer of pyrophosphate through a nucleophilic substitution (SN2) reaction. We show that pppGpp—but not ppGpp—positively regulates SAS1 at an allosteric site. Although the physiological significance remains to be elucidated, we establish the structural and mechanistic basis for a biological activity in which ppGpp and pppGpp execute different functional roles.
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影响因子：
16
作者：
Liu, Kuanqing;Myers, Angela R.;Pisithkul, Tippapha;Claas, Kathy R.;Satyshur, Kenneth A.;Amador-Noguez, Daniel;Keck, James L.;Wang, Jue D.
通讯作者：
Wang, Jue D.
影响因子：
16
作者：
Kriel, Allison;Bittner, Alycia N.;Kim, Sok Ho;Liu, Kuanqing;Tehranchi, Ashley K.;Zou, Winnie Y.;Rendon, Samantha;Chen, Rui;Tu, Benjamin P.;Wang, Jue D.
通讯作者：
Wang, Jue D.
影响因子：
5.4
作者：
Liu K;Bittner AN;Wang JD
通讯作者：
Wang JD
影响因子：
15.9
作者：
Boutte, Cara C.;Crosson, Sean
通讯作者：
Crosson, Sean
影响因子：
2.9
作者：
Avarbock, D;Avarbock, A;Rubin, H
通讯作者：
Rubin, H