Biomolecular Mass Spectrometry: Applications to Proteins and Peptides - Molecules: Nucleation, Aggregation and Crystallization - page 66

Fig. 5. Addition of Rsd (indicated as X) to the RNA polymerase holoenzyme (H). The
holoenzyme alone (bottom spectrum) compared to addition of equimolar amount of Rsd
(middle spectrum), and with two molar excess of Rsd (top spectrum) shows the appear-
ance of a species which corresponds in mass to a 1:1 complex of Rsd-

70 , indicating a reor-
ganization of the holoenzyme. Inset shows Rsd and the components of the holoenzyme.

σ

modification on the yeast ribosomal stalk proteins (Hanson et al ., 2004).
Furthermore, by assessing dissociated products from the samples, a com-
plex with a mass not attributable to any known ribosomal protein(s) was
observed. By employing further tandem MS on this complex, it turns out