Attribution rates for MS/MS spectra, obtained with sample-specific metagenomics databases. Databases were generated using the following workflows: FragGeneScan only (FGS), MEGAHIT and FragGeneScan (MGH-FGS), MEGAHIT and six-frame translation (MGH-6RF), sixgill, and PLASS. The results obtained when using the complete databases are indicated 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 shown on the left. Searches were performed at decoy-free FDR 1% and results are ordered based on the database size, using a logarithmic X-axis. 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.