4GGD image
Deposition Date 2012-08-06
Release Date 2012-11-07
Last Version Date 2024-02-28
Entry Detail
PDB ID:
4GGD
Keywords:
Title:
Structural analysis of human Cdc20 supports multisite degron recognition by APC/C.
Biological Source:
Source Organism:
Homo sapiens (Taxon ID: 9606)
Host Organism:
Method Details:
Experimental Method:
Resolution:
2.44 Å
R-Value Free:
0.20
R-Value Work:
0.15
R-Value Observed:
0.15
Space Group:
P 1 21 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Cell division cycle protein 20 homolog
Gene (Uniprot):CDC20
Chain IDs:A, B
Chain Length:431
Number of Molecules:2
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Molecule:Mitotic checkpoint serine/threonine-protein kinase BUB1 beta
Gene (Uniprot):BUB1B
Chain IDs:C, D
Chain Length:23
Number of Molecules:2
Biological Source:Homo sapiens
Primary Citation
Structural analysis of human Cdc20 supports multisite degron recognition by APC/C.
Proc.Natl.Acad.Sci.USA 109 18419 18424 (2012)
PMID: 23091007 DOI: 10.1073/pnas.1213438109

Abstact

The anaphase-promoting complex/cyclosome (APC/C) promotes anaphase onset and mitotic exit through ubiquitinating securin and cyclin B1. The mitotic APC/C activator, the cell division cycle 20 (Cdc20) protein, directly interacts with APC/C degrons--the destruction (D) and KEN boxes. APC/C(Cdc20) is the target of the spindle checkpoint. Checkpoint inhibition of APC/C(Cdc20) requires the binding of a BubR1 KEN box to Cdc20. How APC/C recognizes substrates is not understood. We report the crystal structures of human Cdc20 alone or bound to a BubR1 KEN box. Cdc20 has a disordered N-terminal region and a C-terminal WD40 β propeller with a preformed KEN-box-binding site at its top face. We identify a second conserved surface at the side of the Cdc20 β propeller as a D-box-binding site. The D box of securin, but not its KEN box, is critical for securin ubiquitination by APC/C(Cdc20). Although both motifs contribute to securin ubiquitination by APC/C(Cdh1), securin mutants lacking either motif are efficiently ubiquitinated. Furthermore, D-box peptides diminish the ubiquitination of KEN-box substrates by APC/C(Cdh1), suggesting possible competition between the two motifs. Our results indicate the lack of strong positive cooperativity between the two degrons of securin. We propose that low-cooperativity, multisite target recognition enables APC/C to robustly ubiquitinate diverse substrates and helps to drive cell cycle oscillations.

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