Bacterial Flageller

[beecee]

https://mobile.the-scientist.com/article/53504/image-of-the-day-bacterial-flagella

http://advances.sciencemag.org/content/4/4/eaao7054

Insight into structural remodeling of the FlhA ring responsible for bacterial flagellar type III protein export

 

Abstract

The bacterial flagellum is a supramolecular motility machine. Flagellar assembly begins with the basal body, followed by the hook and finally the filament. A carboxyl-terminal cytoplasmic domain of FlhA (FlhA_C) forms a nonameric ring structure in the flagellar type III protein export apparatus and coordinates flagellar protein export with assembly. However, the mechanism of this process remains unknown. We report that a flexible linker of FlhA_C (FlhA_L) is required not only for FlhA_C ring formation but also for substrate specificity switching of the protein export apparatus from the hook protein to the filament protein upon completion of the hook structure. FlhA_L was required for cooperative ring formation of FlhA_C. Alanine substitutions of residues involved in FlhA_C ring formation interfered with the substrate specificity switching, thereby inhibiting filament assembly at the hook tip. These observations lead us to propose a mechanistic model for export switching involving structural remodeling of FlhA_C.

 

OK, I'm not sure if I understand properly what is happening here...Can someone enlighten?

[CharonY]

It is called flagella (plural of flagellum). Which part do you have problems with. Or perhaps it is easier if you try to formulate what you think is happening?

[beecee]

On 5/23/2018 at 1:16 AM, CharonY said:

It is called flagella (plural of flagellum). Which part do you have problems with. Or perhaps it is easier if you try to formulate what you think is happening?

My ignorance of this is extreme! My guess rightly or wrongly was in relation to basic simple life forms, creating and/or evolving into more complicated life forms. 

[CharonY]

Sorry, but that does not make it clearer to me. Are you wondering what a flagellum is? I am unclear why you would think it relates to complex life forms. Flagella are found many bacteria and is one very common mechanisms of locomotion.

[beecee]

6 minutes ago, CharonY said:

Sorry, but that does not make it clearer to me. Are you wondering what a flagellum is? I am unclear why you would think it relates to complex life forms. Flagella are found many bacteria and is one very common mechanisms of locomotion.

Like I said, I'm ignorant on this subject, and if my thoughts are wrong, then can you basically describe in words of simplicity [as much as possible] as to what is actually going on?  

[CharonY]

It would help if you could frame your question a bit. I am literally not clear what you mean with "what is going on" and how it relates to the article you posted. The question is just so broad and just listing all what is known about flagella is nothing that I would be able (nor willing) to put into a single post. In short, flagella are long protein structures produced by bacteria to move around. The article that you have posted describes the the mechanism (itself consisting of proteins) involved in the production to this structure. Maybe you want to at least read the wikipedia article on the topic and if you want, ask specific questions? 

[beecee]

5 hours ago, CharonY said:

It would help if you could frame your question a bit. I am literally not clear what you mean with "what is going on" and how it relates to the article you posted. Maybe you want to at least read the wikipedia article on the topic and if you want, ask specific questions? 

Did just that....slightly clearer now, obviously  this  "bacterial flagellar motor' [of which I had no idea of prior]  appears to be a rotary biological "engine" inside bacteria. How am I going?  This aids in the production and distribution of protein, although as yet the exact mechanism is unknown. I was probably more surprised and unaware that this knowledge existed. Pretty snazzy.

Edited May 25, 2018 by beecee

[CharonY]

There are in fact several moving elements. One is the secretion system, which moves the building blocks of the flagellum outside of the cell and assembles them (which is what the paper is about) the other is the actual motor that rotates the assembled flagellum. The basic machinery is fairly well known, but some of the molecular interactions are more speculative than others.

[BabcockHall]

Each E coli cell has about half a dozen flagella.  They act as screw propellers.  When all rotate in the same direction, the bacterial cell moves forward.  When some rotate in one direction and others rotate in the opposite direction, the bacterium tumbles, and will then swim in a new direction.  This is how chemotaxis occurs.  The flagellum is powered by the proton motive force.  I think of it as an electric motor of a sort.  Other species are different in the specifics.  One problem that the E. coli cell must solve is how to export the proteins and assemble the flagellum from its constituent proteins.

Edited May 25, 2018 by BabcockHall

[beecee]

8 hours ago, CharonY said:

There are in fact several moving elements. One is the secretion system, which moves the building blocks of the flagellum outside of the cell and assembles them (which is what the paper is about) the other is the actual motor that rotates the assembled flagellum. The basic machinery is fairly well known, but some of the molecular interactions are more speculative than others.

 

5 hours ago, BabcockHall said:

Each E coli cell has about half a dozen flagella.  They act as screw propellers.  When all rotate in the same direction, the bacterial cell moves forward.  When some rotate in one direction and others rotate in the opposite direction, the bacterium tumbles, and will then swim in a new direction.  This is how chemotaxis occurs.  The flagellum is powered by the proton motive force.  I think of it as an electric motor of a sort.  Other species are different in the specifics.  One problem that the E. coli cell must solve is how to export the proteins and assemble the flagellum from its constituent proteins.

Vinaka vakalevu fellas!