Vasodilator-stimulated phosphoprotein(VASP)

The vasodilator-stimulated phosphoprotein (VASP) is a key regulator of actin dynamics (See image below). The 45-residue-long tetramerization domain (red) is shown by Jmol. It forms a right-handed alpha-helical coiled-coil. Unlike the left-handed coiled-coils, with a 7 residue repeat, the VASP TD has a 15-residue repeat. Leu residues at a spacing of 15 aa can be seen to stabilize the helix bundle by hydrophobic interactions. In addition there are a series of ion pairs between helices, as shown by the magenta glutamates and cyan lysines, creating an extremely stable complex.

The VASP tetramerization domain is a right-handed coiled coil based on a 15-residue repeat.(PubMed)
Kühnel K, Jarchau T, Wolf E, Schlichting I, Walter U, Wittinghofer A, Strelkov SV.
Proc Natl Acad Sci U S A. 2004 Dec 7;101(49):17027-32

2iae (PDB)