A0A4

A0A4 is not a standalone biological term but a prefix used in the accession numbering system for protein sequences in UniProt. It identifies a subset of entries that originate from automated or high-throughput annotation pipelines, typically part of the TrEMBL portion of UniProtKB. In practice, A0A4 indicates the beginning of a unique accession code assigned to a protein sequence, and each entry carries a complete alphanumeric code such as A0A4W3XQF0 that distinguishes it within the database.

The accession system in UniProt serves to catalog protein sequences from across species and sources. Prefixes like A0A4 help distinguish automatically annotated entries from manually reviewed ones and from other accession groups. The presence of the A0A4 prefix does not convey functional information about the protein; rather, it signals that the entry may be computationally predicted and not yet curated in detail.

Role and limitations: A0A4 entries provide a placeholder for newly identified or predicted proteins. They may lack experimental validation or detailed functional annotations. As a result, researchers should treat these entries as provisional and cross-reference with curated, experimentally supported data when drawing conclusions about protein function, structure, or biological role.

Use in research: Researchers use A0A4 and other accession prefixes to retrieve sequence data, predicted features, and cross-references to related records. For high-confidence insights, they typically consult reviewed UniProt entries or supplementary resources and may look for experimental evidence in primary literature.

See also: UniProt accession numbers, UniProtKB, TrEMBL, protein databases.