@article {18721,
	title = {Structure of the S5a:K48-Linked Diubiquitin Complex and Its Interactions with Rpn13},
	journal = {Molecular Cell},
	volume = {35},
	year = {2009},
	month = {2009/08/14/},
	pages = {280 - 290},
	abstract = {SummaryDegradation by the proteasome typically requires substrate ubiquitination. Two ubiquitin receptors exist in the proteasome, S5a/Rpn10 and Rpn13. Whereas Rpn13 has only one ubiquitin-binding surface, S5a binds ubiquitin with two independent ubiquitin-interacting motifs (UIMs). Here, we use nuclear magnetic resonance (NMR) and analytical ultracentrifugation to define at atomic level resolution how S5a binds K48-linked diubiquitin, in which K48 of~one ubiquitin subunit (the {\textquotedblleft}proximal{\textquotedblright} one) is covalently bonded to G76 of the other (the {\textquotedblleft}distal{\textquotedblright} subunit). We demonstrate that S5a{\textquoteright}s UIMs bind the two subunits simultaneously with a preference for UIM2 binding to the proximal subunit while UIM1 binds to the distal one. In addition, NMR experiments reveal that Rpn13 and S5a bind K48-linked diubiquitin simultaneously with subunit specificity, and a model structure of S5a and Rpn13 bound to K48-linked polyubiquitin is provided. Altogether, our data demonstrate that S5a is highly adaptive and cooperative toward binding ubiquitin chains.
},
	keywords = {Proteins},
	isbn = {1097-2765},
	doi = {10.1016/j.molcel.2009.06.010},
	url = {http://www.sciencedirect.com/science/article/pii/S1097276509004018},
	author = {Zhang,Naixia and Wang,Qinghua and Ehlinger,Aaron and Randles,Leah and Lary,Jeffrey W. and Kang,Yang and Haririnia,Aydin and Storaska,Andrew J. and Cole,James L. and Fushman, David and Walters,Kylie J.}
}
