Table 1

Statistics of data collection and structure determination. For data collection, the crystals were harvested in a buffer containing 20% glycerol as cryo-protectant and then frozen rapidly in liquid nitrogen. The crystals are small (up to 150 μm in the largest dimension) and diffract x-rays weakly. They belong to the monoclinic space group P21 with unit cell dimensions a = 135.9 Å, b = 175.3 Å,c = 139.2 Å, and β = 91.6°. Assuming one F1c10 complex with 453.2 kD per asymmetric unit, the estimated solvent content is 66%. A data set was collected to 3.6 Å resolution at beamline ID02B (λ = 0.99 Å), at the ESRF, Grenoble, France, with a Mar Research image plate detector (1600 pixel mode). The data were processed with MOSFLM (73) and SCALA/CCP4 (54). Because of anisotropic diffraction and slight radiation damage, the final data set was restricted to 3.9 Å resolution.

Resolution shell (Å) 12.33 8.72 7.12 6.17 5.525.03 4.66 4.36 4.11 3.90 Overall (15–3.9)
Number of observations 1343 32074159 49345600 6229 6765 7312 77568288 55593
Completeness (%) 69.8 92.2   92.8  93.3   93.5 94.1 94.1 94.8 94.5 95.593.3
Rmerge* (%) 5.8 5.6   6.7    8.7   10.4 11.9 12.0 14.322.1 37.2 10.0
I7.2 6.6   7.4    6.7    6.3 5.5 5.4 4.73.3 1.3 4.0
Resolution range15.0–5.0 Å
Molecular replacement correlation cofficient54.1 (44.0)
Molecular replacementR factor (%) 46.7 (50.6)
  • * Rmerge: ΣhΣi[|I(h,i)− 〈I(h)〉|]ΣhΣiI(h,i), whereI(h,i)is the intensity value of the ith measurement ofh and 〈I(h,i)〉 is the corresponding mean value of h for all imeasurements of h. The summation runs over all measurements.

  • Values for the second highest solution are given in parentheses.

  • R factor: Σ∥Fobs|−|Fcalc∥/Σ|Fobs|, where Fobs and Fcalc are the observed and calculated structure factor amplitudes, respectively.