Real-time kinetics of electrogenic Na(+) transport by rhodopsin from the marine flavobacterium Dokdonia sp. PRO95.
Real-time kinetics of electrogenic Na(+) transport by rhodopsin from the marine flavobacterium Dokdonia sp. PRO95.
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电淡蛋白从海洋黄杆菌dokdonia sp。的电源Na（+）转运的实时动力学。 Pro95。
DOI：
10.1038/srep21397
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发表时间：
2016-02-11
影响因子：
4.6
通讯作者：
Skulachev VP
中科院分区：
文献类型：
--
作者：
Bogachev AV;Bertsova YV;Verkhovskaya ML;Mamedov MD;Skulachev VP
光驱动钠泵Na+-视紫红质（NaR）的发现，引发了对这种新型膜连接能量转换器的分子机制的研究。在本文中，我们研究了NaR从海洋黄杆菌Dokdonia sp.PRO95的光循环，并确定了产电和Na+依赖的步骤，这个周期。我们发现NaR光循环至少由四个步骤组成：NaR 519 + hv → K585 →（L450 ParticipM 495）→ O 585 → NaR 519。第三步是唯一的一步，这取决于内的Na+浓度的右侧出含NaR的脂蛋白体，这表明这一步是与Na+结合NaR耦合。对于步骤2、3和4，速率常数值分别为4×104 s-1、4.7 × 103 M-1 s-1和150 s-1。这些步骤贡献了由掺入脂质体并附着于磷脂浸渍的火棉胶膜的NaR的单次周转产生的总膜电位（Δ R ~ 200 mV）的15、15和70%。在此基础上，提出了光驱动NaR抽运Na ~+的机制。
Discovery of the light-driven sodium-motive pump Na+-rhodopsin (NaR) has initiated studies of the molecular mechanism of this novel membrane-linked energy transducer. In this paper, we investigated the photocycle of NaR from the marine flavobacterium Dokdonia sp. PRO95 and identified electrogenic and Na+-dependent steps of this cycle. We found that the NaR photocycle is composed of at least four steps: NaR519 + hv → K585 → (L450↔M495) → O585 → NaR519. The third step is the only step that depends on the Na+ concentration inside right-side-out NaR-containing proteoliposomes, indicating that this step is coupled with Na+ binding to NaR. For steps 2, 3, and 4, the values of the rate constants are 4×104 s–1, 4.7 × 103 M–1 s–1, and 150 s–1, respectively. These steps contributed 15, 15, and 70% of the total membrane electric potential (Δψ ~ 200 mV) generated by a single turnover of NaR incorporated into liposomes and attached to phospholipid-impregnated collodion film. On the basis of these observations, a mechanism of light-driven Na+ pumping by NaR is suggested.