Fig. 1.

A, Native mass spectrum of intact Cascade, showing a dominant charge state distribution that is consistent with a species of 405,365 ± 135 Da. Two additional subcomplexes were identified having molecular masses of 349,399 ± 84 Da (Cascade lacking Cse1) and 42,524 ± 8 Da (dimeric Cse2, inset). B, Mass spectrum of Cascade sprayed from a solution containing 5% iso-propanol, triggering in solution dissociation of the complex. Several additional charge state distributions that correspond to Cascade subcomplexes were identified. All complexes annotated in (A) and (B) are indicated by colors shown in the inset on the right. C, Native mass spectrum of the Csy system of Pseudomonas aeruginosa, showing a dominant charge state distribution that is consistent with a the intact complex of 350,414 ± 22 Da. Satellite peaks originate from incomplete removal of the purification tag of Csy4, one of the complex components, from the complex resulting into a complex mass of 352,494 ± 16. In addition two subcomplexes were identified having molecular masses of 265,307 ± 9 Da, lacking both Csy1 and Csy2, and a dimeric subcomplex of the endoribonuclease Csy4 and crRNA (40.867 Da), see inset. Adapted from (22).