The controlled adsorption or proteins to well-defined monolayers is critical to advances in sensor and nanotechnology applications where selective adsorption of targeted species is of interest. In the Studies reported here, we developed vibrational spectroscopic methods to gain molecular insight into the effect of single-site versus multiple-site binding or proteins to metal-chelating monolayers at in air-water interface. Analysis of real-time planar array infrared reflection-absorption spectra revealed that a Cu(II)-chelated DSIDA lipid monolayer (Cu2+-DSIDA) was readily disrupted by adsorption of myoglobin as demonstrated by a blue shift of 1.7 cm(-1) in the nu(as)(CH2) stretching mode and a reduced peak intensity over a period of 5 h. However, a Zn(II)-chelated monolayer was not affected by the adsorption of either protein, suggesting that multisite binding of protein on the Cu2+-DSIDA results in monolayer disruption. Further studies demonstrated that in film form, adsorption of myoglobin to the Cu2+-DSIDA perturbed the secondary structures of myoglobin, especially the alpha-helical, random Structure, and extended structures. However, no distinct change was observed during adsorption of lysozyme. These results demonstrate the utility of these methods for monitoring the molecular rearrangement of both metal-charged lipid monolayers and proteins that occur during adsorption of a protein with a strong affinity for the monolayer.