1avo
From Proteopedia
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PROTEASOME ACTIVATOR REG(ALPHA)
Overview
The specificity of the 20S proteasome, which degrades many intracellular, proteins, is regulated by protein complexes that bind to one or both ends, of the cylindrical proteasome structure. One of these regulatory, complexes, the 11S regulator (known as REG or PA28), stimulates proteasome, peptidase activity and enhances the production of antigenic peptides for, presentation by class I molecules of the major histocompatibility complex, (MHC). The three REG subunits that have been identified, REGalpha, REGbeta, and REGgamma (also known as the Ki antigen), share extensive sequence, similarity, apart from a highly variable internal segment of 17-34, residues which may confer subunit-specific properties. REGalpha and, REGbeta preferentially form a heteromeric complex, although purified, REGalpha forms a heptamer in solution and has biochemical properties, similar to the heteromeric REGalpha/REGbeta complex. We have now, determined the crystal structure of human recombinant REGalpha at 2.8 A, resolution. The heptameric barrel-shaped assembly contains a central, channel that has an opening of 20 A diameter at one end and another of 30, A diameter at the presumed proteasome-binding surface. The binding of REG, probably causes conformational changes that open a pore in the proteasome, alpha-subunits through which substrates and products can pass.
About this Structure
1AVO is a Protein complex structure of sequences from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Structure of the proteasome activator REGalpha (PA28alpha)., Knowlton JR, Johnston SC, Whitby FG, Realini C, Zhang Z, Rechsteiner M, Hill CP, Nature. 1997 Dec 11;390(6660):639-43. PMID:9403698
Page seeded by OCA on Fri Feb 15 15:29:56 2008
