Annexins [1,2,3,4,5,6] are a group of calcium-binding proteins that associate
reversibly with membranes. They bind to phospholipid bilayers in the
presence of micromolar free calcium concentration. The binding is specific
for calcium and for acidic phospholipids. Annexins have been claimed to be
involved in cytoskeletal interactions, phospholipase inhibition, intracellular
signalling, anticoagulation, and membrane fusion.
Each of these proteins consist of an N-terminal domain of variable length
followed by four or eight copies of a conserved segment of sixty one residues.
The repeat (sometimes known as an 'endonexin fold') consists of five α-helices that are wound into a right-handed superhelix .
The proteins known to belong to the annexin family are listed below:
Annexin I (Lipocortin 1) (Calpactin 2) (p35) (Chromobindin 9).
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