CryoEM + Native MS + Crosslinking = complete protein complex pictures!

I just sat through a great talk on Cryo-EM. Which is interesting because a lot of them are showing up in Maryland. If you haven't seen these things, I suggest you look some stuff up on them. You  can visualize intact proteins and tell - from the image - how many subunits you have and stuff!

One of the papers mentioned in the talk was this new one done in conjunction with the Heck lab!

Why is it on this blog? Cause Cryo only fills in the part of the picture (and you have to have a really big protein or you can't see it)

This is really cool because we're almost completely complementary technologies. CryoEM gives you an image of the structure -- native mass spec can give you the mass of the structure. Breaking  the noncovalent interactions of the individual protein groups can get you subunit exact masses for MS1 (or, better yet, top down!).  (Oh..and if the protein complex is so big it is hard to get native MS, chances are you just LOOK AT IT WITH A MICROSCOPE!!)

This study goes one step further, but you don't really see much about it till you get pretty deep in the supplemental info. They chemically crosslink and digest the whole thing for LC-MS/MS shotgun and BOOM! probably way more (j/k!) than you wanted to know about this protein complex!  In this case they reveal the internal workings of how some incredibly simple organisms maintain their circadian rhythm.