S-100A11: S-100A11 domain found in proteins similar to S100A11. S100A11 is a member of the S-100 domain family within EF-hand Ca2+-binding proteins superfamily. Note that the S-100 hierarchy, to which this S-100A11 group belongs, contains only S-100 EF-hand domains, other EF-hands have been modeled separately. S100 proteins exhibit unique patterns of tissue- and cell type-specific expression and have been implicated in the Ca2+-dependent regulation of diverse physiological processes, including cell cycle regulation, differentiation, growth, and metabolic control . S100 proteins have also been associated with a variety of pathological events, including neoplastic transformation and neurodegenerative diseases such as Alzheimer's, usually via over expression of the protein. S100A11 is expressed in smooth muscle and other tissues and involves in calcium-dependent membrane aggregation, which is important for cell vesiculation . As is the case for many other S100 proteins, S100A11 is homodimer, which is able to form a heterodimer with S100B through subunit exchange. Ca2+ binding to S100A11 results in a conformational change in the protein, exposing a hydrophobic surface that interacts with target proteins. In addition to binding to annexin A1 and A6 S100A11 also interacts with actin and transglutaminase.
Structure:1QLS_A, pig S100c bound with calcium ions, contacts at 3.5 A
Comment:the N-terminal EF hand is a S100 specific feature while the C-terminal canonical EF hand is similar to the EF hands in calmodulin, troponin C, and parvalbumin
Comment:the second binding site (C-terminal EF hand) has a greater affinity for Ca2+ than the first (N-terminal EF hand)
Jiyao W et al.(2023). "The conserved domain database in 2023.",