2.B.31 The Synthetic Linear Ionophoric Peptide (LIP) Family
Two linear synthetic peptides, N-tBoc-Pro-Gly-Ala-NHCH3 and N-tBoc-Pro-D-Ala-Ala-NHCH3, complex Ca2+ and form 2:1 (peptide:calcium) complexes. They also bind Pr3+ (praseodymium, a soft, silvery, malleable and ductile metal). Like most rare earth elements, praseodymium most readily forms the +3 oxidation state, which is the only stable state in aqueous solution. These peptides mediate transport of Pr3+ across dimyristoylphosphatidylcholine unilamellar vesicles via a 2:1 ion-sandwich complex (Shastri et al. 1986).