Figure 1: (a) Normalized thermal UV-denaturation profiles of the RPS12 pre-mRNA from Trypanosoma brucei (colored, solid lines) at different buffered solvent conditions. Red/orange: crowded solvent conditions (6% (w/w) PEG4000). Blue/cyan: dilute solvent conditions. Dark colors: 2 mM Mg2+. Bright colors: no Mg2+. Dashed traces: normalized 1st derivatives () of the different melting profiles. Five helix-coil transitions are marked with arrows. (b) Difference () UV-melting profiles (dilute minus crowded conditions) in the presence/absence of Mg2+-cations (black/grey). (c) Shifting of the UV-denaturation profiles to higher temperatures expressed as versus of the dilute condition in presence/absence of Mg2+-cations (black/grey).