We have investigated the contribution of main chain hydrogen bond (H-bond) pathways to the tunneling matrix elements which control electron transfer (ET) rates across an alpha-helical protein matrix. The paradigm system for these investigations is a metal ion-assembled parallel three-helix bundle protein that contains a ruthenium(II) tris(bipyridyl) electron donor and a ruthenium(III) pentammine electron acceptor separated by a direct metal to metal distance of ca. 19 Angstrom, requiring tunneling through 15 Angstrom of alpha-helical peptide. The putative ET pathway was modulated by a synthetic strategy in which specific main chain amide moieties along an alpha-helix were replaced by ester linkages that cannot form equivalent H-bonds. A simple pathway analysis implies a role for such H-bonds in facilitating electron transfer. Within the accuracy of the computational predictions, specific H-bonded pathway models do not predict the differences in the measured ET rates between the parent construct and the different H-bond deletion variants.