Attribution rates for MS/MS spectra when using generic databases. The results obtained with SGC and NCBI are shown as a function of the database size using a logarithmic X-axis. The results obtained with the whole databases are presented on the right (one-step search), whereas the results obtained on refined databases containing proteins selected at distinct p-values during the first-round search are indicated on the left (two-step search). The SGC+NCBI databases were obtained by merging the reduced NCBI and SGC protein databases at each p-value cutoff. Searches were performed at decoy-free FDR 1%. The small numbers indicate the p-value threshold used for each search. Three biological replicates were used to calculate the mean and standard deviation values.