Chaperone priming of pilus subunits facilitates a topological transition that drives fiber formation
Chaperone priming of pilus subunits facilitates a topological transition that drives fiber formation
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DOI：
10.1016/s0092-8674(02)01050-4
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发表时间：
2002-11-15
期刊：
影响因子：
64.5
通讯作者：
Hultgren, SJ
中科院分区：
文献类型：
--
作者：
Sauer, FG;Pinkner, JS;Hultgren, SJ
周质伴侣指导粘附性多亚基菌毛纤维的组装，这些纤维在细菌发病机制中发挥着关键作用。菌毛组装通过供体链交换机制发生，其中一个亚基的 N 端延伸取代了暂时占据相邻亚基凹槽的伴侣 G(1) 链。在这里，我们表明伴侣通过将凹槽保持在开放的激活构象来为亚基组装做好准备。在供体链交换过程中，亚基经历拓扑转变，触发凹槽闭合并将 N 端延伸密封到位。这种拓扑转变只有通过分子伴侣的启动作用才能实现，驱动亚基组装到纤维中。
Periplasmic chaperones direct the assembly of adhesive, multi-subunit pilus fibers that play critical roles in bacterial pathogenesis. Pilus assembly occurs via a donor strand exchange mechanism in which the N-terminal extension of one subunit replaces the chaperone G(1) strand that transiently occupies a groove in the neighboring subunit. Here, we show that the chaperone primes the subunit for assembly by holding the groove in an open, activated conformation. During donor strand exchange, the subunit undergoes a topological transition that triggers the closure of the groove and seals the N-terminal extension in place. It is this topological transition, made possible only by the priming action of the chaperone that drives subunit assembly into the fiber.