1FNT

CRYSTAL STRUCTURE OF THE 20S PROTEASOME FROM YEAST IN COMPLEX WITH THE PROTEASOME ACTIVATOR PA26 FROM TRYPANOSOME BRUCEI AT 3.2 ANGSTROMS RESOLUTION

Summary for 1FNT

• Entry DOI: 10.2210/pdb1fnt/pdb
• Related: 1avo 1ryp
• Descriptor: PROTEASOME COMPONENT C7-ALPHA, PROTEASOME COMPONENT PUP3, PROTEASOME COMPONENT C11, ... (16 entities in total)
• Functional Keywords: multicatalytic proteinase, 20s proteasome, protein degradation, antigen processing, protease, proteasome activator, cell adhesion, interferon induction, hydrolase-hydrolase activator complex, hydrolase/hydrolase activator
• Biological source: Saccharomyces cerevisiae (baker's yeast); More
• Cellular location: Cytoplasm : P21243 P25451 P22141 P30656 P23724 P30657 P23639 P23638 P40303 P32379 P40302 P21242 P38624 P25043
• Total number of polymer chains: 42
• Total formula weight: 1079359.66

Authors

Whitby, F.G.,Masters, E.,Kramer, L.,Knowlton, J.R.,Yao, Y.,Wang, C.C.,Hill, C.P. (deposition date: 2000-08-23, release date: 2001-04-11, Last modification date: 2024-04-03)

Primary citation

Whitby, F.G.,Masters, E.I.,Kramer, L.,Knowlton, J.R.,Yao, Y.,Wang, C.C.,Hill, C.P.
Structural basis for the activation of 20S proteasomes by 11S regulators.
Nature, 408:115-120, 2000

PubMed Abstract: Most of the non-lysosomal proteolysis that occurs in eukaryotic cells is performed by a nonspecific and abundant barrel-shaped complex called the 20S proteasome. Substrates access the active sites, which are sequestered in an internal chamber, by traversing a narrow opening (alpha-annulus) that is blocked in the unliganded 20S proteasome by amino-terminal sequences of alpha-subunits. Peptide products probably exit the 20S proteasome through the same opening. 11S regulators (also called PA26 (ref. 4), PA28 (ref. 5) and REG) are heptamers that stimulate 20S proteasome peptidase activity in vitro and may facilitate product release in vivo. Here we report the co-crystal structure of yeast 20S proteasome with the 11S regulator from Trypanosoma brucei (PA26). PA26 carboxy-terminal tails provide binding affinity by inserting into pockets on the 20S proteasome, and PA26 activation loops induce conformational changes in alpha-subunits that open the gate separating the proteasome interior from the intracellular environment. The reduction in processivity expected for an open conformation of the exit gate may explain the role of 11S regulators in the production of ligands for major histocompatibility complex class I molecules.

PubMed: 11081519
DOI: 10.1038/35040607

Experimental method

X-RAY DIFFRACTION (3.2 Å)