Research press release


Nature Structural & Molecular Biology

Unfolding the story of an anthrax toxin

Nature Structural & Molecular Biology(電子版)の論文で、炭疽毒素が細胞に入り込む仕組みが視覚化されている。炭疽菌の生活環における基本的な過程を生じる機構を理解することで、こうした病原菌の弱点を探し出すことができる。

炭疽菌(Bacillus anthracis)は炭疽の原因となる細菌で、致死因子(LF)という毒素を作り出し、これがいったん細胞に入り込むと患者を死に至らしめる。しかし、宿主細胞への毒素タンパク質の注入は、びんの中に船を入れるようなもので、折りたたみをほどいて細胞の狭いチャネルを通り抜け、細胞内で活性な形に再び折りたたまなければならない。


How the anthrax toxin gets into cells is visualized in a paper published online this week in Nature Structural & Molecular Biology. Understanding the machinery underlying such a basic process in the anthrax lifecycle allows researchers to look for weak spots to target such pathogens.

Bacillus anthracis, the bacterium that causes anthrax, produces the toxin lethal factor (LF), which, once it enters cells, leads to fatality for patients. But injecting these proteins into host cells is akin to getting a ship into a bottle, in that they have to be unfolded to get them through a narrow channel into the cell where they are refolded into their active shape.

The anthrax lethal toxin injection system itself consists of protective antigen (PA) and lethal factor (LF), with LF unfolding for translocation into the host cell. Structural and functional analyses indicate how each of four LF molecules unfolds and binds on the surface of eight PA molecules in clefts that help stabilize the unfolded state. This indicates how the bacterium can control the shape of the molecule and ensure it remains functional.

doi: 10.1038/nsmb.1923


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