Using four oligopeptide-specific polyclonal antibodies, we mapped the α subunit ofNa,K-ATPase by double-labeling immunoelectron microscopy combined with negative staining. The results show that the epitopes of the N-tenninus (Gly1-His13), C-terminus (Ile1002-Tyr1016) and Leu815-Gln828 are located on the same face of crystallized Na,K-ATPase membranes from pig kidney, whereas the epitope Asn889-Gln903 is present on the opposite side. The present study demonstrates the cytoplasmic location of C-terminus and that Leu828-Gln828 is exposed on the eytoplasmic and Asn889-Gln903 on the extracellular side. The results are consistent with an eight- or ten-segment model, and support the existence of an M5/M6 loop and the presence of one transmembrane segment between Leu815-Gln828 and Asn889-Gln903.
All Science Journal Classification (ASJC) codes
- Structural Biology
- Molecular Biology
- Cell Biology