Secondary structure of the plasma membrane ATPase of corn roots (Zea mais L.): An attenuated total reflection FTIR spectroscopy study

The attenuated total reflection ATR-FTIR technique was used to investigate the secondary structure of the plasma membrane H+-ATPase of corn roots. In order to point out the differences and similarities between the secondary structure of the plasma membrane H+-ATPase of plants and of other P-type ATPases, we have compared the FTIR spectra of the corn root H+-ATPase to that of the Neurospora crassa plasma membrane H+-ATPase and of the H+/K+-ATPase from the gastric hog. Comparison with the amide I of the two other P-ATPase indicates a roughly similar shape but with a distinct difference in the region of the β-sheet, with less β-sheet contribution in the case of the corn roots H+-ATPase but more α-helix. It is concluded that significant structural differences may exist within the P-type ATPase family.