A SMILE · analyse Soluble + Membrane complexes with Improved LILBID Experiments

Crucial processes within cells depend on specific non-covalent interactions which mediate the assembly of proteins and other biomolecules. Deriving structural information to understand the function of these complex systems is the primary goal of Structural Biology.In this application, the recently developed LILBID method (Laser Induced Liquid Bead Ion Desorption) will be optimized for investigation of macromolecular complexes with a mass accuracy two orders of magnitude better than in 1st generation spectrometers.Controlled disassembly of the multiprotein complexes in the mass spectrometric analysis while keeping the 3D structure intact, will allow for the determination of complex stoichiometry and connectivity of the constituting proteins. Methods for such controlled disassembly will be developed in two separate units of the proposed LILBID spectrometer, in a collision chamber and in a laser dissociation chamber, enabling gas phase dissociation of protein complexes and removal of excess water/buffer molecules. As a third unit, a chamber allowing determination of ion mobility (IM) will be integrated to determine collisional cross sections (CCS). From CCS, unique information regarding the spatial arrangement of proteins in complexes or subcomplexes will then be obtainable from LILBID.The proposed design of the new spectrometer will offer fundamentally new possibilities for the investigation of non-covalent RNA, soluble and membrane protein complexes, as well as broadening the applicability of non-covalent MS towards supercomplexes.