Mass Spec is leading the charge in bringing high-throughput proteomics to a lab near you
Mass Spec: It's not just for chemistry nerds anymore.
It's one of the most important techniques in proteomics!
Proteomics is the study of proteins, how they function and how they interact with other molecules within our cells and tissues.
Understanding what all of those proteins are doing is important.
But not just for our own education!
Malfunctioning, missing, or improperly regulated proteins are generally what cause disease.
And quantifying what proteins are present or how they are regulated with post-translational modifications (PTMs) can tell us a lot about how they're functioning in a cell or tissue!
But, there are a number of ways we can analyze proteins.
These can include using antibodies, sequencing them directly, or detecting them with mass spectrometry (mass spec).
While the last one might sound intimidating, it’s currently the most informative of the 3!
And recent innovations have allowed these instruments to detect thousands of proteins in a single sample, including their PTMs which are important on/off switches for proteins!
Knowing that a protein is present is useful, but knowing how it is modified tells you a whole lot more about what it's doing.
Mass spec is currently the only technique capable of reliably getting both of these forms of data in a single output.
And it’s able to do this by ionizing proteins and smashing them into a detector to determine their mass-to-charge ratio or m/z.
This m/z information can then be used to figure out the original chemical composition of the things that were smashed!
There are a couple different flavors here that are worth mentioning:
LC-MS(/MS) - Liquid chromatography - tandem mass spectrometry (two detectors) is probably the simplest form of mass spec used in proteomics. LC here is used to crudely separate proteins before they’re ionized and smashed.
MALDI-TOF - Matrix assisted laser desorption/ionization - time-of-flight is a version of mass spec where the ionization of the sample is done after combining it with a ‘matrix’ that allows it to be more completely ionized. Time-of-flight (a long tube) is added to this scheme to better separate ions of different masses (the big ones take longer to hit the detector) and gives superior resolution over traditional LC-MS!
timsTOF - Adds another fun twist to time-of-flight mass spectrometry by sticking a gas tube ahead of the TOF tube to trap ions and selectively release them based on their m/z to increase resolution even further.
Orbitrap - This is something totally different although the readout is the same and it’s the highest resolution option (also the most expensive)! There’s no smashing in this setup (WTF?) but the system is able to determine the m/z of the ionized proteins as they travel in an elliptical path around a detector.
While high-throughput proteomics is still evolving, the mass spec space is one to watch closely!
Read the full issue of Omic.ly Premium 11
Brian Krueger