Thursday, February 25, 2016

"High capacity" ETD massively boosts sequence coverage of intact proteins!

ETD is a valuable tool for sequencing intact proteins. We've known that for a long time. But its also tough to work with. One problem is how much signal you end up losing which forces you to use things like scan averaging, which slows everything down.

Nicholas Riley et al., have a solution to this problem. High capacity ETD!  I'm a little hazy on how it works. Instrument physics isn't my thing, but my understanding is that they used a standard Orbitrap Lumos and tweaked the code a little to contain and fragment the ions a little differently.

What I do get? The massive boost in coverage!

Check that out!  They mostly worked with small proteins for this study, up to 29kDa. But the top is normal ETD and the bottom is their new high capacity ETD. Almost double the number of fragments (they did the fragment analysis with the free Prosight Lite, btw!

More coverage is aweseome, but the cooler thing is probably that they could get lots of coverage WITH FEWER MICROSCANS!  (Sorry, my caplock got stuck). When I help someone set up a top down experiment, that is the killer. You take this super fast Orbitrap but then you microscan (scan average) a bunch so that you get enough signal, so the speed of the instrument comes way down. But if those microscans weren't as necessary? Holy cow.  Massive increases in what you'll identify in top down runs!

Now, if you're thinking: "Wow. That is cool and all, but I'm not going to be hacking the software on my Fusion or Lumos, so who cares?"  Turns out its already equipped on the Lumos!

Another interesting note!  An NBA sharpshooting legend appears be doing a lot of mass spectrometry these days.  Wait...have I made this joke before?


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