The effect of counterions on melittin aggregation.
Melittin, a surface-active polypeptide from bee venom, has an overall hydrophobic N-terminus, with basic residues clustered at the C-terminus. In aqueous solution melittin exists as a mixture of monomer and tetramer, the monomer adopting a predominantly random-coil configuration, whereas the tetramer is rich in alpha-helix. The tendency of melittin to aggregate is dependent on the counter-anions present in solution, the effect being most marked with phosphate, decreasing in the order HPO4(2-) greater than SO4(2-) greater than ClO4- greater than Cl-.
D000595:Amino Acid Sequence; D000838:Anions; D001514:Bee Venoms; D055598:Chemical Phenomena; D002621:Chemistry; D002712:Chlorides; D002942:Circular Dichroism; D046911:Macromolecular Substances; D008555:Melitten; D010710:Phosphates; D011487:Protein Conformation; D013431:Sulfates
D000838:Anions; D001514:Bee Venoms; D002712:Chlorides; D046911:Macromolecular Substances; D010710:Phosphates; D013431:Sulfates; D008555:Melitten