Image analysis of electron micrographs of ATPase (Coupling Factor TF1) from thermophilic bacteria and luminal epithelium of mouse urinary bladder.

: Electron micrographs of two dimensional array of H+-ATPase (Coupling Factor TF1 from the thermophilic bacteria) and luminal epithelial protein of urinary bladder were obtained using negative staining method and freeze-fracture method, respectively. Images which showed good optical diffraction pattern were digitized by a computer-linked flat-bed two dimensional microdensitometer and processed digitally. The results of translational computer noise filtering showed that the outline of TF1 molecules looks like a hexagon or an asterisk in the presence of sodium azide which is a specific inhibitor of TF1 or AMPPNP which is an unsplitable analogue of ATP, respectively. The luminal epithelial protein also looks like a hexagon. Rotational harmonic analysis was carried out to examine the rotational symmetry of the filtered images of TF1. It was found that 2-fold or 6-fold symmetry is dominant in the presence of sodium azide or AMPPNP, respectively.