Resonance Raman spectra for zucchini, cucumber, bean, and lettuce plastocyanins, blue copper proteins involved in plant photosynthetic electron transport, have been measured at wavelengths throughout their intense 600-nm absorption band. A comparison of the resonance Raman spectra of these four plastocyanins, and two others previously quantified, demonstrates that they all exhibit vibrational bands with similar frequencies but significantly different relative intensities. Self-consistent analysis of the absorption band and resulting resonance Raman excitation profiles using a time-dependent wave packet formalism for these four plastocyanins demonstrates that many of the derived molecular parameters are similar to those determined previously for two other species of plastocyanin. However, significant differences are observed in the mode-specific displacements and reorganization energies, although the total reorganization energy is 0.6 +/- 0.01 eV for all six plastocyanins. A detailed comparison of the structural and compositional differences among the six plastocyanins, using the previously reported structure of poplar a plastocyanin, suggests that these mode-specific differences arise from specific amino acid differences within 10-12 Angstrom of the copper site. These results are interpreted as arising from a through-bond mode-mixing mechanism and a through-space electrostatic mechanism and suggest that the normal modes of the copper site are delocalized into the protein. In addition, lettuce plastocyanin has a significantly greater homogeneous line width, probably as a result of compositional differences adjacent to the copper active site. These results demonstrate that the protein environment is strongly coupled to. or mixed in with the copper site vibrational dynamics. Further evidence. for the sensitivity of the resonance Raman intensities to particular electron-transfer pathways within the protein is also discussed.