New structural and functional contexts of the Dx[DN]xDG linear motif: insights into evolution of calcium-binding proteins.

ABSTRACT: Binding of calcium ions (Ca²⁺) to proteins can have profound effects on their structure and function. Common roles of calcium binding include structure stabilization and regulation of activity. It is known that diverse families--EF-hands being one of at least twelve--use a Dx[DN]xDG linear motif to bind calcium in near-identical fashion. Here, four novel structural contexts for the motif are described. Existing experimental data for one of them, a thermophilic archaeal subtilisin, demonstrate for the first time a role for Dx[DN]xDG-bound calcium in protein folding. An integrin-like embedding of the motif in the blade of a β-propeller fold--here named the calcium blade--is discovered in structures of bacterial and fungal proteins. Furthermore, sensitive database searches suggest a common or

SUBMITTER: Rigden DJ 

PROVIDER: S-EPMC3123361 | biostudies-literature | 2011

REPOSITORIES: biostudies-literature