What's the meaning of UniProt features without fixed begin and end?

Question

[Kveta]

Hi everyone,

When protein annotations are downloaded from UniProt in JSON format, some features have begin and end values like ~338, >250 or <15. I know these mean that the exact position is uncertain and the feature may extend beyond it (example).
However, these features are not displayed in the ProtVista viewer available through UniProt (example). Why are they not shown? Is it a bug in the viewer or is it intentional?

Thanks in advance.

Answer 1

[Elisabeth Gasteiger]

Thanks for pointing this out.

Your understanding of the uncertain feature positions is absolutely correct (see https://www.uniprot.org/help/sequence_annotation). It seems to be a bug indeed that they are not displayed in the feature viewer. I have passed the issue on the the developers of the viewer.