A series of ferrocene (Fc)- and cystamine (CSA)-labeled peptides of the sequence [Fc-(Pro-Pro-Gly)(n)-CSA](2), where n = 1-3, was synthesized and characterized. Peptide 3 forms a trimeric supramolecular structure held together with extensive hydrogen bonding and adopts a collagen-like motif in solution. Cyclic voltammetry (CV) and chronoamperometry (CA) were used to calculate electron-transfer (ET) kinetics. ET rates were 10.9 (2.3) x 10(3), 6.6 (1.9) x 10(3), and 4.2 (1.2) x 10(3) s(-1) for peptides where n = 1, 2, and 3, respectively. The peptides, under deuterated conditions (D2O, full exchange of H for D), showed rate constants of 7.3 (1.3) x 10(3), 5.8 (1.0) x 10(3), and 3.4 (0.5) x 10(3) s(-1) for n = 1, 2, and 3, respectively. A linear dependence of the ET rate constant and distance is found.