Characterization of epitopes of the yeast mitochondrial H+-ATPase complex recognized by monoclonal antibodies.
Nine monoclonal antibodies which react with the beta subunit of the yeast mitochondrial H+-ATPase and three which react with a 25 kDa subunit of the enzyme complex (P25) have been characterized. Competitive binding studies indicated the presence of at least four antigenic regions on the beta subunit of the enzyme complex. One antigenic region of the beta subunit is recognized by two monoclonal antibodies RH 57.1 and RH 45.5 which inhibit the ATPase activity to different degrees. Antibody RH 48.6 appears to bind to a second region on the beta subunit and has no effect on the ATPase activity. A third region of the beta subunit is recognized by antibodies RH 51.4 and RH 72.1. RH 51.4 has no effect on the ATPase activity, whereas RH 72.1 stimulates ATPase activity. Antibody RH 32.4 which has no effect on the ATPase activity appears to bind to the fourth epitope of the beta subunit. All three monoclonal anti-P25 antibodies, RH 66.3, RH 41.2 and RH 37.0, apparently bind to the same antigenic region on this subunit. Two of the monoclonal anti-beta antibodies RH 48.6 and RH 51.4 were found to be very effective in immunoprecipitating the whole H+-ATPase complex in a solid phase system. However, the other monoclonal antibodies (and also a polyclonal antiserum) appear to induce the dissociation of one or more of the H+-ATPase subunits by their binding to the epitopes on the beta or the P25 subunits.
R G
RG
Hadikusumo
P J
PJ
Hertzog
S
S
Marzuki
D000908:Antibodies, Fungal / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology; D000946:Antigens, Fungal / Q000276:immunology; D001667:Binding, Competitive; D000939:Epitopes / Q000276:immunology*; D005656:Fungal Proteins / Q000276:immunology*; D008928:Mitochondria / Q000201:enzymology*; D006180:Proton-Translocating ATPases / Q000276:immunology*; D015003:Yeasts / Q000201:enzymology / Q000276:immunology
D000908:Antibodies, Fungal; D000911:Antibodies, Monoclonal; D000946:Antigens, Fungal; D000939:Epitopes; D005656:Fungal Proteins; D006180:Proton-Translocating ATPases