1yx5
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Solution Structure of S5a UIM-1/Ubiquitin Complex
OverviewOverview
Ubiquitin is a key regulatory molecule in diverse cellular events. How cells determine the outcome of ubiquitylation remains unclear; however, a likely determinant is the specificity of ubiquitin receptor proteins for polyubiquitin chains of certain length and linkage. Proteasome subunit S5a contains two ubiquitin-interacting motifs (UIMs) through which it recruits ubiquitylated substrates to the proteasome for their degradation. Here, we report the structure of S5a (196-306) alone and complexed with two monoubiquitin molecules. This construct contains the two UIMs of S5a and we reveal their different ubiquitin-binding mechanisms and provide a rationale for their unique specificities for different ubiquitin-like domains. Furthermore, we provide direct evidence that S5a (196-306) binds either K63-linked or K48-linked polyubiquitin, and in both cases prefers longer chains. On the basis of these results we present a model for how S5a and other ubiquitin-binding proteins recognize polyubiquitin.
DiseaseDisease
Known disease associated with this structure: Cleft palate, isolated OMIM:[191339]
About this StructureAbout this Structure
1YX5 is a Protein complex structure of sequences from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Structure of S5a bound to monoubiquitin provides a model for polyubiquitin recognition., Wang Q, Young P, Walters KJ, J Mol Biol. 2005 May 6;348(3):727-39. PMID:15826667
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