ATPASE OF RHODOSPIRILLUM-RUBRUM REQUIRES 3 FUNCTIONAL COPIES OF BETA-SUBUNIT AS DETERMINED BY RADIATION INACTIVATION ANALYSIS

[[abstract]]Radiation inactivation analysis yielded a functional unit of 170 +/- 26 kDa as beta subunit of ATPase was irradiated and then reconstituted to beta-depleted chromatophores of Rhodospirillum rubrum. A functional size of 132 +/- 17 kDa for the beta-depleted ATPase moiety involved in ATP hydrolysis reaction was also determined. When both purified beta subunit and beta-depleted chromatophore were irradiated separately, reconstituted, and then activity measured, the functional mass was 312 +/- 50 kDa. Our compelling evidence directly indicates that three functional copies of beta subunits were required for ATP hydrolysis.[[fileno]]2050111010046[[department]]生科