Bacterial motors carefully studied:flagellum sequence (Introduction)

by David Turell , Saturday, April 28, 2018, 05:21 (2184 days ago) @ dhw

It takes 70+ specific genes to make a flagellum:

https://phys.org/news/2018-04-bacterial-propeller.html

"Many bacteria are equipped with a flagellum, a helical propeller that allows bacteria to travel. The flagellum is assembled in a highly organized manner involving the stepwise addition of each of its internal parts. However, there are many open questions as to how this orderly construction is achieved.

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"'Flagellar assembly is a complex process involving more than 70 genes," lead author Naoya Terahara explains. "First, the basal motor is assembled, followed by the hook, and finally the helical filament. Each structure is built by sending a unique set of proteins to the site of assembly. The cell can somehow sense when each structure is complete, triggering a switch to export the next series of proteins. We wanted to develop a more detailed picture of how this switching occurs.

"The export machinery sits at the base of the flagellum, and is made from nine copies of a protein that form a ring. The ring acts like a gatekeeper, selecting which proteins will travel out to the growing flagellum. The ring is incredibly small—mere nanometers in diameter—making precise analysis relatively difficult. To gain insight into this machinery, the researchers used high-speed atomic force microscopy. The approach, conducted through a collaborative effort with researchers at Kanazawa University, allowed the team to directly visualize the ring. By then making mutations in the ring, they could pinpoint which regions were responsible for triggering the export switch.

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"'Our findings suggest that subtle changes in the ring's shape determine which proteins are exported to the growing flagellum," lead investigator Tohru Minamino explains. "Once the hook has been assembled, contact points in the ring shift slightly, altering the ring's shape and allowing helical filament proteins to travel through."

"The proposed model may have a significant impact on research into bacterial infections: the flagellum shares many similarities to the injectisome, a needle-like structure used by infectious bacteria to deliver proteins to their host. The study may thus serve as a map to better guide infectious disease research."

Comment: Of course atheists believe this all happened by chance. Doesn't seem reasonable to me. 70+ genes just got together naturally. Really?