Mass Spectrometry

Mass spectrometry is a powerful technique that is increasingly used in the field of structural molecular biology as it offers the following advantages:

1) High sensitivity, allowing the analysis of endogenously expressed proteins and protein complexes
2) Ability to analyse several co-existing species present in a mixture
3) Monitoring of binding events and subunit exchange processes

Recently, mass spectrometry has been coupled to ion mobility spectrometry. Ion mobility is a gas-phase technique that separates ions based on their rotationally averaged collision cross-section (CCS) and charge. Ion mobility mass spectrometry offers additional advantages to mass spectrometry alone such as:

1) The ability to distinguish between co-existing forms of a protein
2) Ability to study proteins of high flexibility
3) Experimental CCSs are in excellent agreement with those calculated from X-ray and NMR structures allowing the use of experimental CCSs to filter computer-generated models of oligomers
4) The ability to monitor and separate distinct conformational families co-existing in solution, such as in the case of oligomer formation

The ISMB houses a first generation Waters Synapt, the first commercially introduced ion mobility mass spectrometer. The Synapt in the ISMB has been modified for the analysis of very large ions such that analysis of protein complexes of up to 1 MDa are now possible.

Researchers interested in using this technology should contact Dr Kostas Thalassinos.