Department of Biology, Indiana University, 1001 E. 3rd Street, Bloomington, IN 47405, USA.
Biology Department, CUNY Brooklyn College, 2900 Bedford Avenue, Brooklyn, NY 11210, USA.
Sci Adv. 2019 Dec 18;5(12):eaay2591. doi: 10.1126/sciadv.aay2591. eCollection 2019 Dec.
A widespread class of prokaryotic motors powered by secretion motor adenosine triphosphatases (ATPases) drives the dynamic extension and retraction of extracellular fibers, such as type IV pili (T4P). Among these, the tight adherence (tad) pili are critical for surface sensing and biofilm formation. As for most other motors belonging to this class, how tad pili retract despite lacking a dedicated retraction motor ATPase has remained a mystery. Here, we find that a bifunctional pilus motor ATPase, CpaF, drives both activities through adenosine 5'-triphosphate (ATP) hydrolysis. We show that mutations within CpaF result in a correlated reduction in the rates of extension and retraction that directly scales with decreased ATP hydrolysis and retraction force. Thus, a single motor ATPase drives the bidirectional processes of pilus fiber extension and retraction.
一类广泛存在的原核马达由分泌马达三磷酸腺苷酶（ATPases）驱动，它驱动细胞外纤维的动态延伸和回缩，如 IV 型菌毛（T4P）。在这些菌毛中，紧密附着（tad）菌毛对于表面感应和生物膜形成至关重要。对于这个家族的大多数其他马达来说，尽管 tad 菌毛缺乏专用的回缩马达 ATPase，但它们是如何回缩的仍然是个谜。在这里，我们发现一种双功能菌毛马达 ATP 酶 CpaF 通过三磷酸腺苷（ATP）水解来驱动这两种活性。我们表明，CpaF 内的突变导致延伸和回缩速率的相关性降低，这与 ATP 水解和回缩力的降低直接相关。因此，单个马达 ATP 酶驱动菌毛纤维延伸和回缩的双向过程。
