Table 1

Selected crystal data and refinement parameters

ParameterTrigonal formCubic form
Space groupP3221I213
Cell constants, Åa, b = 30.16, c = 140.28107.81
Wavelength, Å1.001.08
Unique reflections21,4625,034
Resolution, Å1.252.85
Completeness, %99.1100
Rsym*, %7.95.4
RNA atoms, waters709, 200677, 14
Metal ions6 Mg2+, 3 Na+, 1 K+
R work, R test (%)14.2, 20.727.1, 27.5
rms distance (Å), angles (°)0.005, 1.300.009, 1.00
  • * Rsym = ∑hkli|I(hkl)i − 〈I(hkl)〉|/∑hkliI(hkl)i〉. 

  • R = ∑hkl|F(hkl)oF(hkl)c|/∑hklF(hkl)o

  • For 10% of the data (30).