Flagella stator homologs function as motors for myxobacterial gliding motility by moving in helical trajectories
Flagella stator homologs function as motors for myxobacterial gliding motility by moving in helical trajectories
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DOI：
10.1073/pnas.1219982110
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发表时间：
2013-04-16
影响因子：
11.1
通讯作者：
Zusman, David R.
中科院分区：
文献类型：
--
作者：
Nan, Beiyan;Bandaria, Jigar N.;Zusman, David R.
许多细菌在自然栖息地使用滑行运动，因为外部鞭毛在坚硬表面上的功能很差。然而，由于表面运动结构不明显，滑翔的机制仍然难以捉摸。在这里，我们表征了黄粘球菌滑动马达蛋白AglR的动力学，这是大肠杆菌鞭毛定子蛋白MotA的同源物。我们观察到AglR具有螺旋结构，当细胞悬浮在液体中或细胞在琼脂表面移动时，AglR螺旋会旋转。通过光激活定位显微镜，我们发现与MotA/MotB不同，AglR的单分子可以在膜内沿螺旋轨迹横向移动。AglR在滑行表面瞬间减速，聚集成簇。我们的研究表明，黄原草的无系绳滑动马达，通过在膜内移动，可以将螺旋运动转化为线性驱动力，推动表面。
Many bacterial species use gliding motility in natural habitats because external flagella function poorly on hard surfaces. However, the mechanism(s) of gliding remain elusive because surface motility structures are not apparent. Here, we characterized the dynamics of the Myxococcus xanthus gliding motor protein AglR, a homolog of the Escherichia coli flagella stator protein MotA. We observed that AglR decorated a helical structure, and the AglR helices rotated when cells were suspended in liquid or when cells moved on agar surfaces. With photoactivatable localization microscopy, we found that single molecules of AglR, unlike MotA/MotB, can move laterally within the membrane in helical trajectories. AglR slowed down transiently at gliding surfaces, accumulating in clusters. Our work shows that the untethered gliding motors of M. xanthus, by moving within the membrane, can transform helical motion into linear driving forces that push against the surface.