title: Evidence for macromolecular protein rings in the absence of bulk water.
abstract: We have examined the architecture of a protein complex in the absence of bulk water. By determining collision cross sections of assemblies of the trp RNA binding protein, TRAP, we established that the 11-membered ring topology of the complex can be maintained within a mass spectrometer. We also found that the binding of tryptophan enhances the stability of the ring structure and that addition of a specific RNA molecule increases the size of the complex and prevents structural collapse. These results provide definitive evidence that protein quaternary structure can be maintained in the absence of bulk water and highlight the potential of ion mobility separation for defining shapes of heterogeneous macromolecular assemblies.
authors.affiliation: Department of Chemistry, Lensfield Road, University of Cambridge, Cambridge CB2 1EW, UK.
authors.forename: Brandon T
authors.initials: BT
authors.lastname: Ruotolo
authors.forename: Kevin
authors.initials: K
authors.lastname: Giles
authors.forename: Iain
authors.initials: I
authors.lastname: Campuzano
authors.forename: Alan M
authors.initials: AM
authors.lastname: Sandercock
authors.forename: Robert H
authors.initials: RH
authors.lastname: Bateman
authors.forename: Carol V
authors.initials: CV
authors.lastname: Robinson
mesh_terms: D020121:5' Untranslated Regions / Q000378:metabolism; D001059:Apoproteins / Q000737:chemistry / Q000378:metabolism; D001412:Bacillus subtilis; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D007477:Ions / Q000737:chemistry; D011487:Protein Conformation; D020836:Protein Structure, Quaternary; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization; D013816:Thermodynamics; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism; D014364:Tryptophan / Q000378:metabolism; D014867:Water
chemical_list: D020121:5' Untranslated Regions; D001059:Apoproteins; D001426:Bacterial Proteins; D007477:Ions; C079092:MtrB protein, Bacteria; D021122:Protein Subunits; D016601:RNA-Binding Proteins; D014157:Transcription Factors; D014867:Water; D014364:Tryptophan