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首页> 外文期刊>Infection and immunity >Retrieving Biological Activity from LukF-PV Mutants Combined with Different S Components Implies Compatibility between the Stem Domains of These Staphylococcal Bicomponent Leucotoxins
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Retrieving Biological Activity from LukF-PV Mutants Combined with Different S Components Implies Compatibility between the Stem Domains of These Staphylococcal Bicomponent Leucotoxins

机译：从LukF-PV突变体与不同的S组分结合检索生物活性暗示这些葡萄球菌双组分白细胞毒素的茎域之间的兼容性。

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Bicomponent leucotoxins, such as Panton-Valentine leucocidin, are composed of two classes of proteins, a class S protein such as LukS-PV, which bears the cell membrane binding function, and a class F protein such as LukF-PV, which interacts to form a bipartite hexameric pore. These leucotoxins induce cell activation, linked to a Ca2+ influx, and pore formation as two consecutive and independently inhibitable events. Knowledge of the LukF-PV monomer structure has indicated that the stem domain is folded into three antiparallel β-strands in the water-soluble form and has to refold into a transmembrane β-hairpin during pore formation. To investigate the requirements for the cooperative assembly of the stems of the S and F components to produce biological activity, we introduced multiple deletions or single point mutations into the stem domains of LukF-PV and HlgB. While the binding of the mutated proteins was weakly dependent on these changes, Ca2+ influx and pore formation were affected differently, confirming that they are independent events. Ca2+ entry into human polymorphonuclear cells requires oligomerization and may follow the formation of a prepore. The activity of some of the LukF-PV mutants, carrying the shorter deletions, was actually improved. This demonstrated that a crucial event in the action of these toxins is the transition of the prefolded stem into the extended β-hairpins and that this step may be facilitated by small deletions that remove some of the interactions stabilizing the folded structure.
机译：双组分白细胞毒素，例如Panton-Valentine leucocidin，由两类蛋白质组成，一种是S类蛋白质，例如具有细胞膜结合功能的LukS-PV，另一种是F类蛋白质，例如与细胞相互作用的LukF-PV。形成一个二元六聚体孔。这些白细胞毒素诱导细胞活化，并与Ca 2 + 大量涌入相关，并形成孔，这是两个连续且独立抑制的事件。对LukF-PV单体结构的了解表明，茎结构域以水溶性形式折叠成三个反平行的β链，并且在孔形成过程中必须重新折叠成跨膜β-发夹结构。为了调查S和F组件的茎协同组装以产生生物活性的要求，我们将多个缺失或单点突变引入了LukF-PV和HlgB的茎域中。尽管突变蛋白的结合微弱地依赖于这些变化，但Ca 2 + 的流入和孔形成受到的影响却不同，从而证实它们是独立的事件。 Ca 2 + 进入人多形核细胞需要低聚，并可能跟随前孔的形成。实际上，一些带有较短缺失的LukF-PV突变体的活性得到了改善。这证明了在这些毒素的作用中的关键事件是预折叠茎向延长的β-发夹的过渡，并且该步骤可以通过去除一些使折叠结构稳定的相互作用的小缺失来促进。

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