Bacteria firing powerful spikes with hats

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I guess you remember the T6SS arrow bacteria use to fire into other bacteria. Different lethal toxins are attached to this arrow. When bacteria fire this arrow together with the toxins nearby prey bacteria, this usually leads to death of the prey bacterium.

In this study we look at the very tip of the arrow, because on top of the spike of the arrow sits another protein. We call this protein PAAR and it is a super sharp protein. This sharp needle-like protein helps to punch a hole into the prey bacterium. So this super sharp PAAR protein seems to be quite important for the firing and punching process.

Our beloved bacterium Pseudomonas aeruginosa contains seven different PAAR and ten different spike proteins. However, we still don’t know which PAAR sits on top of which spike and which of the PAARs plays a double role and occupies two spikes.

Here we focused on an arrow that is composed of three G2b spike proteins. We already knew that G2b is a special spike protein because it contains an extension which at the same time is a toxin. Then we could also show that the toxin Tle3 binds to the G2b spike and is delivered together with this spike.

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Bacteria firing powerful spikes with hats

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Sarah Wettstadt

Science Writer, MicroComms

Dr Sarah Wettstadt is a microbiologist-turned science writer and communicator working on various outreach projects and helping researchers talk and write about their scientific results. Her overall vision is to empower through learning: she shares scientific knowledge with both scientists and non-scientists and coaches scientists in writing about their research. Sarah is blog commissioner for the FEMSmicroBlog and was a social media editor for FEMS for 1.5 years. Furthermore, she writes the blog BacterialWorld explaining bacterial concepts and co-founded the STEM-video platform STEMcognito. Previous to her science communication career, she worked as a postdoc in Marían Llamas’ lab on Pseudomonas aeruginosa’s ability to use heterologous iron sources and completed her PhD with Alain Filloux investigating the type 6 secretion system in Pseudomonas aeruginosa.