Ankyrins are a family of proteins that mediate the attachment of integral membrane proteins to the spectrin-actin based membrane cytoskeleton. Ankyrins have binding sites for the beta subunit of spectrin and at least 12 families of integral membrane proteins. This linkage is required to maintain the integrity of the plasma membranes and to anchor specific ion channels, ion exchangers and ion transporters in the plasma membrane. The 24 tandem ankyrin repeats are responsible for the recognition of a wide range of membrane proteins. These 24 repeats contain 3 structurally distinct binding sites ranging from repeat 1-14. These binding sites are quasi-independent of each other and can be used in combination. The interactions the sites use to bind to membrane proteins are non-specific and consist of: hydrogen bonding, hydrophobic interactions and electrostatic interactions. These non-specific interactions give ankyrin the property to recognise a large range of proteins as the sequence doesn't have to be conserved, just the properties of the amino acids. The quasi-independence means that if a binding site is not used, it won't have a large effect on the overall binding. These two properties in combination give rise to large repertoire of proteins ankyrin can recognise. Here you can see a recent example of the human ankyrin-1, interacting with a small anionic protein (white tube). Note the induced folding mechanism showed by the ankyrin to recognize the interacting protein. The structure was solved by cryoEM (PDB code: 7V0M)
#molecularart ... #immolecular ... #ankyrin ... #erythrocyte ... #interaction ... #inducedfolding ... #cryoem
Structure rendered with @proteinimaging and depicted with @corelphotopaint
#molecularart ... #immolecular ... #ankyrin ... #erythrocyte ... #interaction ... #inducedfolding ... #cryoem
Structure rendered with @proteinimaging and depicted with @corelphotopaint
