The first type, a matched metagenomic protein database, is built from metagenomes specifically assembled from samples similar to the metaproteomic sample. This approach captures the sample's complexity while minimizing the number of irrelevant sequences, as it is directly based on the genomes of the organisms found in (similar) samples. However, assembling a metagenome from DNA reads and translating it into a metaproteome can introduce errors, potentially reducing accuracy. Nevertheless, this approach remains the preferred method when the required resources and expertise are available.