SID of hexameric Hfq65 (43 kDa) RNA chaperone (using rectilinear design). (a) Mass spectrum of isolated 9+ hexamer, (b) SID spectrum using 85 V of acceleration, yielding overlapping monomers, dimers, trimers, tetramers, and pentamers, and (c) resolution of the overlapping species at m/z 7186. The resolution observed in panel (a) is approximately 197,000 and in panel (c) is approximately 148,000.