title: An Alignment-Free "Metapeptide" Strategy for Metaproteomic Characterization of Microbiome Samples Using Shotgun Metagenomic Sequencing.
abstract: In principle, tandem mass spectrometry can be used to detect and quantify the peptides present in a microbiome sample, enabling functional and taxonomic insight into microbiome metabolic activity. However, the phylogenetic diversity constituting a particular microbiome is often unknown, and many of the organisms present may not have assembled genomes. In ocean microbiome samples, with particularly diverse and uncultured bacterial communities, it is difficult to construct protein databases that contain the bulk of the peptides in the sample without losing detection sensitivity due to the overwhelming number of candidate peptides for each tandem mass spectrum. We describe a method for deriving "metapeptides" (short amino acid sequences that may be represented in multiple organisms) from shotgun metagenomic sequencing of microbiome samples. In two ocean microbiome samples, we constructed site-specific metapeptide databases to detect more than one and a half times as many peptides as by searching against predicted genes from an assembled metagenome and roughly three times as many peptides as by searching against the NCBI environmental proteome database. The increased peptide yield has the potential to enrich the taxonomic and functional characterization of sample metaproteomes.
authors.affiliation: Department of Genome Sciences and ‡Department of Computer Science and Engineering, University of Washington , Seattle, Washington 98195-5065, United States.
authors.forename: Damon H
authors.initials: DH
authors.lastname: May
authors.affiliation: Department of Genome Sciences and ‡Department of Computer Science and Engineering, University of Washington , Seattle, Washington 98195-5065, United States.
authors.forename: Emma
authors.initials: E
authors.lastname: Timmins-Schiffman
authors.affiliation: Department of Ocean, Earth & Atmospheric Sciences, Old Dominion University , Norfolk, Virginia 23529, United States.
authors.forename: Molly P
authors.initials: MP
authors.lastname: Mikan
authors.affiliation: Department of Ocean, Earth & Atmospheric Sciences, Old Dominion University , Norfolk, Virginia 23529, United States.
authors.forename: H Rodger
authors.initials: HR
authors.lastname: Harvey
authors.affiliation: Department of Genome Sciences and ‡Department of Computer Science and Engineering, University of Washington , Seattle, Washington 98195-5065, United States.|Santa Fe Institute , Santa Fe, New Mexico 87501, United States.
authors.forename: Elhanan
authors.initials: E
authors.lastname: Borenstein
authors.affiliation: Department of Genome Sciences and ‡Department of Computer Science and Engineering, University of Washington , Seattle, Washington 98195-5065, United States.
authors.forename: Brook L
authors.initials: BL
authors.lastname: Nunn
authors.affiliation: Department of Genome Sciences and ‡Department of Computer Science and Engineering, University of Washington , Seattle, Washington 98195-5065, United States.
authors.forename: William S
authors.initials: WS
authors.lastname: Noble
mesh_terms: D059001:Aquatic Organisms / Q000737:chemistry* / Q000235:genetics; D044822:Biodiversity; D030562:Databases, Protein; D056186:Metagenomics / Q000379:methods*; D064307:Microbiota / Q000235:genetics; D010455:Peptides / Q000032:analysis*; D040901:Proteomics / Q000379:methods*; D017422:Sequence Analysis, DNA; D013048:Specimen Handling; D053719:Tandem Mass Spectrometry
chemical_list: D010455:Peptides
keywords: mass spectrometry; metagenomics; metaproteomics; microbial communities; microbial ecology