Figure 5
Data quality statistics for the merged structure factor intensities from thermolysin. (a, b, c) Cumulative distribution function N(L) of the local statistic: L = (I1-I2)/(I1+I2), where I1 and I2 are unrelated intensities (Padilla & Yeates, 2003). (d, e, f) Cumulative distribution function N(z), where z = I/〈I〉. Identical data were processed with the protocols listed in Table 1: (a, d) protocol 4, lattice model is not restrained against proximity to the Ewald sphere; (b, e) protocols 6 and 6F, proximity restraints are applied, with and without a separate resolution cutoff for each lattice; and (c, f) protocols 7POST and 7F,POST, which are the same as protocols 6 and 6F except that crystal orientation is postrefined to maximize agreement with a set of reference intensities as described in the text. Agreement between the merged intensities (thick lines) and the theoretical distribution (thin lines) demonstrates that such statistics offer useful metrics for evaluating different processing protocols, with the postrefined model giving the best agreement with theoretical expectation. |