@article {18718,
	title = {Structural Determinants for Selective Recognition of a Lys48-Linked Polyubiquitin Chain by a UBA Domain},
	journal = {Molecular Cell},
	volume = {18},
	year = {2005},
	month = {2005/06/10/},
	pages = {687 - 698},
	abstract = {SummaryAlthough functional diversity in polyubiquitin chain signaling has been ascribed to the ability of differently linked chains to bind in a distinctive manner to effector proteins, structural models of such interactions have been lacking. Here, we use NMR to unveil the structural basis of selective recognition of Lys48-linked di- and tetraubiquitin chains by the UBA2 domain of hHR23A. Although the interaction of UBA2 with Lys48-linked diubiquitin involves the same hydrophobic surface on each ubiquitin unit as that utilized in monoubiquitin:UBA complexes, our results show how the {\textquotedblleft}closed{\textquotedblright} conformation of Lys48-linked diubiquitin is crucial for high-affinity binding. Moreover, recognition of Lys48-linked diubiquitin involves a unique epitope on UBA, which allows the formation of a sandwich-like diubiqutin:UBA complex. Studies of the UBA-tetraubiquitin interaction suggest that this mode of UBA binding to diubiquitin is relevant for longer chains.
},
	isbn = {1097-2765},
	doi = {10.1016/j.molcel.2005.05.013},
	url = {http://www.sciencedirect.com/science/article/pii/S1097276505013195},
	author = {Varadan,Ranjani and Assfalg,Michael and Raasi,Shahri and Pickart,Cecile and Fushman, David}
}
