This is the C-terminal domain of Arc protein present in found in Rattus norvegicus. The Arc protein modulates the trafficking of AMPA-type glutamate receptors. This domains tertiary structure is similar to the capsid domain of HIV gag protein. The domain is thought to have evolved from the capsid domain of Ty3/Gypsy retrotransposon.
Jiyao W et al.(2023). "The conserved domain database in 2023.",