Structure of the cytosine–cytosine mismatch in the thymidylate synthase mRNA binding site and analysis of its interaction with the aminoglycoside paromomycin

Effect of RNA binding on the NMR spectrum of paromomycin. (A) Chemical structure of paromomycin. Roman numerals indicate the ring numbers. (B) TOCSY spectra of paromomycin acquired at increasing concentrations of RNA. Data were acquired in 10 mM sodium phosphate at pH 6.4, 100 μM EDTA, at 20°C and at paromomycin:TSMC molar ratios of: 10:1, 3.33:1, 2:1, 1.43:1, 1.25:1, and 1:1. The arrows indicate the direction of the peak shifts, with the free assignments labeled.