Distance measurements between manganese(II) and nitroxide spin-labels by DEER determine a binding site of Mn(2+) in the HP92 loop of ribosomal RNA.

Mn(2+) localization in hairpin 92 of the 23S ribosomal RNA (HP92) was obtained using W-band (95 GHz) DEER (double electron-electron resonance) distance measurements between the Mn(2+) ion and nitroxide spin labels on the RNA. It was found to be preferably situated in the minor groove of the double strand region close to the HP92 loop.