1j2q
From Proteopedia
20S proteasome in complex with calpain-Inhibitor I from archaeoglobus fulgidus
Structural highlights
FunctionPSA_ARCFU Component of the proteasome core, a large protease complex with broad specificity involved in protein degradation (By similarity).[HAMAP-Rule:MF_00289_A] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe 20S proteasome (core particle, CP) is a multifunctional protease complex and composed of four heptameric subunit rings arranged in a hollow, barrel-shaped structure. Here, we report the crystal structure of the CP from Archaeoglobus fulgidus at 2.25A resolution. The analysis of the structure of early and late assembly intermediates of this CP gives new insights in the maturation of archaebacterial CPs and indicates similarities to assembly intermediates observed in eukaryotes. We also show a striking difference in mechanism and regulation of substrate access between eukaryotic and archaebacterial 20S proteasomes. While eukaryotic CPs are auto-inhibited by the N-terminal tails of the outer alpha-ring by imposing topological closure with a characteristic sequence motif (YDR-motif) and show regulatory gating this segment is disordered in the CP and differently structured in the alpha(7)-sub-complex of A.fulgidus leaving a pore leading into the particle with a diameter of 13A. Mutagenesis and functional studies indicate the absence of regulatory gating in the archaeal 20S proteasome. Investigations on the maturation and regulation of archaebacterial proteasomes.,Groll M, Brandstetter H, Bartunik H, Bourenkow G, Huber R J Mol Biol. 2003 Mar 14;327(1):75-83. PMID:12614609[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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