Proteomics Standards Initiative's ProForma 2.0: Unifying the Encoding of Proteoforms and Peptidoforms

It is important for the proteomics community to have a standardizedmanner to represent all possible variations of a protein or peptide primary sequence,including natural, chemically induced, and artifactual modifications. The HumanProteome Organization Proteomics Standards Initiative in collaboration with severalmembers of the Consortium for Top-Down Proteomics (CTDP) has developed astandard notation called ProForma 2.0, which is a substantial extension of the originalProForma notation developed by the CTDP. ProForma 2.0 aims to unify therepresentation of proteoforms and peptidoforms. ProForma 2.0 supports use casesneeded for bottom-up and middle-/top-down proteomics approaches and allows theencoding of highly modified proteins and peptides using a human- and machine-readable string. ProForma 2.0 can be used to represent protein modifications in a specified or ambiguous location, designated bymass shifts, chemical formulas, or controlled vocabulary terms, including cross-links (natural and chemical) and atomic isotopes.Notational conventions are based on public controlled vocabularies and ontologies. The most up-to-date full specification documentand information about software implementations are available athttp://psidev.info/proforma.

Automated summary

It is important for the proteomics community to have a standardized manner to represent all possible variations of a protein or peptide primary sequence. The ProForma 2.0 notation aims to unify the representation of proteoforms and peptidoforms, supporting different proteomics approaches and allowing the encoding of highly modified proteins and peptides using a human- and machine-readable string.