Oxygen-Induced Conformational Changes in the PAS-Heme Domain of the Pseudomonas aeruginosa Aer2 Receptor.
Oxygen-Induced Conformational Changes in the PAS-Heme Domain of the Pseudomonas aeruginosa Aer2 Receptor.
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DOI：
10.1021/acs.biochem.1c00452
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发表时间：
2021-08-31
期刊：
影响因子：
2.9
通讯作者：
Watts, Kylie J.
中科院分区：
文献类型：
--
作者：
Orillard, Emilie;Anaya, Selina;Johnson, Mark S.;Watts, Kylie J.
铜绿假单胞菌的Aer 2受体具有O2结合PAS-血红素结构域，其通过远端血红素口袋中的Trp残基稳定O2。Trp旋转~90°与配体结合并启动信号传导。虽然分离的PAS结构域是单体的，但在溶液和氰化物结合的晶体结构中，未配体的结构形成二聚体。这两种结构的叠加表明可能的信号运动，但也预测了配体结合时在二聚体界面的难以置信的冲突。此外，在全长Aer 2二聚体中，PAS夹在多个N-和C-末端HAMP结构域之间，这将可行地限制PAS运动。为了探索PAS二聚体界面和信号诱导的运动在全长Aer 2，我们介绍了半胱氨酸取代，并使用巯基反应性探针在有氧和厌氧条件下检查体内的可及性和残基的接近。在体内，PAS二聚体保留在全长Aer 2在存在和不存在O2的情况下，和二聚体界面是一致的孤立的PAS二聚体结构。O2介导的变化也与PAS N-末端帽分开和C-末端DxT区域靠近在一起的结构预测一致。DxT基序将PAS连接到C-末端HAMP结构域，并且对于PAS-HAMP信号传导至关重要。去除N-末端HAMP结构域改变了远端PAS二聚体界面，并阻止信号传导，即使在信号病变被引入PAS后。因此，N-末端HAMP结构域促进PAS向信号开启构象的O2依赖性转变，阐明了它们在PAS传感结构域上游的作用。
The Aer2 receptor from Pseudomonas aeruginosa has an O2-binding PAS-heme domain that stabilizes O2 via a Trp residue in the distal heme pocket. Trp rotates ~90° to bond with ligand and initiate signaling. Although the isolated PAS domain is monomeric, both in solution and in a cyanide-bound crystal structure, an unliganded structure forms a dimer. An overlay of the two structures suggests possible signaling motions but also predicts implausible clashes at the dimer interface when ligand is bound. Moreover, in a full-length Aer2 dimer, PAS is sandwiched between multiple N- and C-terminal HAMP domains, which would feasibly restrict PAS motions. To explore the PAS dimer interface and signal-induced motions in full-length Aer2, we introduced Cys substitutions and used thiol-reactive probes to examine in vivo accessibility and residue proximities under both aerobic and anaerobic conditions. In vivo, PAS dimers were retained in full-length Aer2 in both the presence and absence of O2, and the dimer interface was consistent with the isolated PAS dimer structure. O2-mediated changes were also consistent with structural predictions where the PAS N-terminal caps move apart and the C-terminal DxT region moves closer together. The DxT motif links PAS to the C-terminal HAMP domains and was critical for PAS-HAMP signaling. Removing the N-terminal HAMP domains altered the distal PAS dimer interface and prevented signaling, even after signal-on lesions were introduced into PAS. The N-terminal HAMP domains thus facilitate the O2-dependent shift of PAS to the signal-on conformation, clarifying their role upstream of the PAS sensing domain.
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影响因子：
3.2
作者：
Garcia, Darysbel;Orillard, Emilie;Watts, Kylie J.
通讯作者：
Watts, Kylie J.
影响因子：
9.8
作者：
Airola MV;Sukomon N;Samanta D;Borbat PP;Freed JH;Watts KJ;Crane BR
通讯作者：
Crane BR
影响因子：
4.5
作者：
Pfiffer, Vanessa;Sarenko, Olga;Hengge, Regine
通讯作者：
Hengge, Regine
影响因子：
2.9
作者：
Lu, JL;Deutsch, C
通讯作者：
Deutsch, C
影响因子：
6.8
作者：
Falke, Joseph J.;Piasta, Kene N.
通讯作者：
Piasta, Kene N.