Proteasome
Proteasome (PRTS) are large protein complexes which degrade unneeded proteins into small polypeptides. The 26S PRTS is composed of a central 20S core particle which contains 4 stacked rings each with several members and two 19S caps. The core particle two outer rings contain 7 alpha subunits which form the PRTS gate. The two inner rings contain 6 beta subunits with protease activity. The 19S cap is composed of a base with 10 proteins six of which are ATPases and a lid which contains 9 proteins which binds polyubiquitin. The images at the left and at the right correspond to one representative Proteasome, i.e. the crystal structure of yeast Proteasome (3gpt).
3D Structures of Proteasome3D Structures of Proteasome
20S particle
3mfe, 3mi0, 2fhg – Mt20S core – Mycobacterium tuberculosis 3gpt, 3gpw, 1g0u – y20S core - yeast 1ryp - y20S core (mutant) 3mka, 3hfa – Mt20S core (mutant) 3c91, 3c92, 1pma – Ta20S core - Themoplasma acidophilum 3h4p – 20S core – Methanocaldococcus janaschii 2h6j, 1q5r – Re20S core (mutant) – Rhodococcus erythropolis 1q5q - Re20S core 1j2q – Af20S core - Archaeoglobus fulgidus 1iru – 20S core - bovine
20S+activator protein
1vsy, 1l5q – y20S core+ Blm10 1z7q, 1fnt – y20S core+PA26 3ipm, 3jrm, 3jse, 3jtl, 1ya7, 1yar, 1yau - Taa-PRTS chains A-G+ Tab-PRTS chains H-N+PA26 chains O-U
20S+inhibitor
3hye, 3gpj, 3dy3, 3dy4, 3e47, 3d29, 3zcy, 3bdm, 2gpl, 2fak, 2f16, 1jd2, 1g65 – y20S core+inhibitor 3h6f, 3h6i, 3hf9, 2fhh – Mt20S core+inhibitor
Partial 20S
2ku1, 2ku2 – Taa-PRTS chains A-G 3fp9 – MtATPase chains A-L 1j2p – Af subunit