Single pilus motor forces exceed 100 pN
Single pilus motor forces exceed 100 pN
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DOI：
10.1073/pnas.242523299
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发表时间：
2002-12-10
影响因子：
11.1
通讯作者：
Sheetz, MP
中科院分区：
文献类型：
--
作者：
Maier, B;Potter, L;Sheetz, MP
IV型菌毛回缩产生的力对淋病奈瑟菌的感染性和DNA转移至关重要。我们研究了菌毛数量和回缩马达NIT在单分子水平上体内力产生中的作用，发现单个回缩事件由单个菌毛纤维产生，并且只有一个NIT复合物为回缩提供动力。收回速度在低力下是恒定的，但在大于40 pN的力下减小，从而给出110 +/- 30 pN的显著高的平均失速力。从ATP耗竭的影响中获得了对力产生的分子机制的进一步见解，ATP耗竭降低了收缩速率，但不降低失速力。能量的考虑表明，一个以上的ATP参与从菌毛去除单个菌毛蛋白亚基。结果是最一致的模型，其中的ATP酶NIT形成一个低聚体，通过合作的构象变化来分解菌毛。
Force production by type IV pilus retraction is critical for infectivity of Neisseria gonorrhoeae and DNA transfer. We investigated the roles of pilus number and the retraction motor, NIT, in force generation in vivo at the single-molecule level and found that individual retraction events are generated by a single pilus fiber, and only one NIT complex powers retraction. Retraction velocity is constant at low forces but decreases at forces greater than 40 pN, giving a remarkably high average stall force of 110 +/- 30 pN. Further insights into the molecular mechanism of force generation are gained from the effect of ATP-depletion, which reduces the rate of retraction but not the stall force. Energetic considerations suggest that more than one ATP is involved in the removal of a single pilin subunit from a pilus. The results are most consistent with a model in which the ATPase NIT forms an oligomer that disassembles the pilus by a cooperative conformational change.