Identification and functional reconstitution of phosphate: sugar phosphate antiport of Staphylococcus aureus.
Identification and functional reconstitution of phosphate: sugar phosphate antiport of Staphylococcus aureus.
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磷酸盐的鉴定和功能重建：金黄色葡萄球菌的糖磷酸盐逆向转运。
DOI：
10.1007/bf01872841
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Maloney,PC
中科院分区：
文献类型：
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作者：
Sonna,LA;Maloney,PC
金黄色葡萄球菌静息细胞表现出由葡萄糖6-磷酸（G6P）或甘油3-磷酸（G3P）诱导的磷酸交换。这些细胞中装载pi的膜囊通过不需要外部能量的电中性交换积累了32pi、2-脱氧葡萄糖6-磷酸（2DG6P）或G3P。另一方面，当囊泡装载了morpholino丙烷磺酸（MOPS）时，只观察到32pi（和l-组氨酸）的运输，在这种情况下，运输依赖于可氧化底物（dl-乳酸）的添加。在这些装载mops的囊泡中，直到将囊泡与piandl -lactate一起预孵育以建立Pi的内部池，才能观察到有机磷酸盐2DG6P和G3P的积累。这种奇特的效应表明2DG6P或G3P的运动是基于与内部Pi的反端口（交换）。膜蛋白的重组使Pi-linked exchange的定量分析成为可能。负载Pi的蛋白脂质体和膜泡对同源的32pi∶Piexchange具有相当的活性（Ki′s分别为2.2和1.4mm， Vmax′s分别为180和83 nmol Pi/min / mg protein），表明交换反应在人工体系中得以完整恢复。其他研究表明，来自G6P或G3P生长的细胞的异源交换对2DG6P （Ki=27 μm）的偏好高于G3P （Ki=1.3mm）和Pi(Ki=2.2mm)，这表明在两种情况下诱导了相同的反转运蛋白。我们认为静息细胞表现出的32pi∶Piexchange反应了一种对6-磷酸糖具有高特异性的反向转运蛋白的运作。在这方面，pi连接的反端口inS。金黄色葡萄球菌类似于新描述的细菌转运体家族中的其他例子，这些转运体使用阴离子交换作为溶质转运的分子基础。
Resting cells ofStaphylococcus aureusdisplayed a phosphate (Pi) exchange that was induced by growth with glucose 6-phosphate (G6P) orsn-glycerol 3-phosphate (G3P). Pi-loaded membrane vesicles from these cells accumulated32Pi, 2-deoxyglucose 6-phosphate (2DG6P) or G3P by an electroneutral exchange that required no external source of energy. On the other hand, when vesicles were loaded with morpholinopropane sulfonic acid (MOPS), only transport of32Pi(andl-histidine) was observed, and in that case transport depended on addition of an oxidizable substrate (dl-lactate). In such MOPS-loaded vesicles, accumulation of the organic phosphates, 2DG6P and G3P, could not be observed until vesicles were preincubated with both Pianddl-lactate to establish an internal pool of Pi. Thistranseffect demonstrates that movement of 2DG6P or G3P is based on an antiport (exchange) with internal Pi.Reconstitution of membrane protein allowed a quantitative analysis of Pi-linked exchange. Pi-loaded proteoliposomes and membrane vesicles had comparable activities for the homologous32Pi∶Piexchange (Ki's of 2.2 and 1.4mm;Vmax's of 180 and 83 nmol Pi/min per mg protein), indicating that the exchange reaction was recovered intact in the artificial system. Other work showed that heterologous exchange from either G6P- or G3P-grown cells had a preference for 2DG6P (Ki=27 μm) over G3P (Ki=1.3mm) and Pi(Ki=2.2mm), suggesting that the same antiporter was induced in both cases. We conclude that32Pi∶Piexchange exhibited by resting cells reflects operation of an antiporter with high specificity for sugar 6-phosphate. In this respect, Pi-linked antiport inS. aureusresembles other examples in a newly described family of bacterial transporters that use anion exchange as the molecular basis of solute transport.