Figure 5.

Native top-down analysis of Hs40S by CDMS and conventional native MS

(A) Detection of dissociation products of Hs40S in tandem MS analysis, by using CDMS. Intact Hs40S ribosomal particles (i.e., the precursor ions) and particles missing the S12 ribosomal protein (the fragment ions) are displayed in orange and blue, respectively, in all three representations, including a 2D histogram, a cumulative m/z spectrum, and the charge histogram. Precursor and fragment ions are clearly separated in m/z and z dimensions.

(B) Native top-down analysis of dissociation products of Hs40S by conventional high-resolution native MS is shown for comparison with CDMS. A composite spectrum is shown displaying low-m/z (red) and high-m/z (blue) fragment ions following the isolation and fragmentation of the most abundant precursor (black) charge state of Hs40S. The inset shows the structure of the Hs40S with dissociating peripheral subunits highlighted in red, orange, and pink. Charge distributions corresponding to the different dissociating products are indicated by solid black lines with the masses shown for the two most abundant high-m/z species. The collisional energies applied in (B) are higher than in (A), and, therefore, subsequent losses of multiple subunits are observed in (B) (e.g., loss of S12 and S19 ribosomal proteins).