[{"from": "human", "value": "Describe this molecule. [C][C][=Branch1][C][=O][/C][=C][/C][=C][Branch1][O][N][C][=Branch1][C][=O][N][C][Ring1][#Branch1][=O][C][C][C@@H1][Branch1][O][C@@H1][Branch1][#Branch1][C@@H1][Branch1][Ring1][C][O][O][O][O]"}, {"from": "gpt", "value": "The molecule is a nucleobase analogue that is uracil substituted with a (1-deoxy-D-ribityl)methyl group at position 6 and a (1E)-3-oxobut-1-en-1-yl group at position 5; one of 20 modifications to the potent microbial riboflavin-based metabolite antigen 5-(2-oxopropylideneamino)-6-D-ribityl aminouracil (5-OP-RU), an activator of mucosal-associated invariant T (MAIT) cells when presented by the MR1 protein (reported in MED:32123373). It has a role as an epitope. It is a nucleobase analogue and a pyrimidone. It is functionally related to a uracil."}]