AtCyp59 is a multidomain cyclophilin from Arabidopsis thaliana that interacts with SR proteins and the C-terminal domain of the RNA polymerase II

Determination of RNA binding specificity of AtCyp59. Nucleotide binding specificity was measured by the UV cross-linking/homoribopolymer competition assay using ³²P-labeled Syn7 RNA and recombinant GST-AtCyp59 protein. Different indicated polymers were added at 10-fold (lanes 2,6,10,14), 50-fold (lanes 3,7,11,15), 200-fold (lanes 4,8,12,16), and 400-fold (lanes 5,9,13,17) excess over Syn7 RNA (calculated in moles of nucleotides). Minus sign (–) (lanes 1,18), cross-linking without any competitor added.