Fig. 5: RRE-II-0/rev complex stoichiometry probed by native MS.
From: Native mass spectrometry reveals the initial binding events of HIV-1 rev to RRE stem II RNA

ESI spectra of 1 µM RRE-II-0 RNA solutions in 9:1 H2O/CH3OH with ~1 mM piperidine (pH ~8.1) and a 1 µM and b 2 µM rev peptide (~10 min incubation time) show signals of free RNA (open circles), 1:1 complex (blue circles), and 1:5 complex (red circles).