Some Structural Features Combination of low overall hydrophobicity and relative high net charge under physiological conditions Blue squares=275folded Red circle=91 IUPs Green circles=130 Predicted IUPs Cyan circle=242 Homologues of IUPs Proteins, 2000, 41,415 A combination of low mean hydrophobicity and high net charge preclude the formation of a hydrophobic cluster and promote an extended conformation 42