Claim: As one of 28 subunits of 20S proteasome, protein proteasome subunit beta type-3 (encoded by the PSMB3 gene) contributes to form a proteolytic environment for substrate degradation, based on evidences of the crystal structures of isolated 20S proteasome complex.
Evidence: Proteasome subunit beta type-3, also known as 20S proteasome subunit beta-3, is a protein that in humans is encoded by the PSMB3 gene. As one of 28 subunits of 20S proteasome, protein proteasome subunit beta type-3 contributes to form a proteolytic environment for substrate degradation. Evidences of the crystal structures of isolated 20S proteasome complex demonstrate that the two rings of beta subunits form a proteolytic chamber and maintain all their active sites of proteolysis within the chamber.