Large protein complexes

Tandem DMA-MS Analysis of the GroEL Complex

Christopher J. Hogan Jr.1,2,3, Brandon T. Ruotolo4, Carol V. Robinson5, Juan Fernandez de la Mora1
1 Department of Mechanical Engineering, Yale University, New Haven, CT, USA
2 SEADM, Boecillo, Spain;
3 Currently at Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, USA;
4Department of Chemistry, University of Michigan, Ann Arbor, MI, USA;
5Department of Chemistry, University of Oxford, Oxford, England, United Kingdom





Figure 1.  

Mobility-mass spectra for GroEL tetradecamers in dry atmospheric air.

Declustering potential applied downstream the DMA: (a) 0 V; (b) 350 V


GroEL tetradecamers were purchased from Sigma-Aldrich (C7688) and purified by the Cambridge group as described by Freeke et al. (Int. J. Mass Spectrom. 2009, In Press).  The GroEL complexes were dissolved in 100 mM aqueous ammonium acetate at a concentration of several μM.  Sample solution was driven through a 40 mm inner diameter capillary (360 μm outer diameter, tapered down to ~60 mm at the outlet, length ~25 cm) with a backing pressure of 0.05 bar. Notice the unusually narrow mobility peaks, even though there is no declustering upstream of the DMA.