THE 2.8-ANGSTROM STRUCTURE OF RAT-LIVER F-1-ATPASE - CONFIGURATION OFA CRITICAL INTERMEDIATE IN ATP SYNTHESIS HYDROLYSIS/

During mitochondrial ATP synthesis, F-1-ATPase-the portion of the;ITP synthase that contains the catalytic and regulatory nucleotide binding sites-undergoes a series of concerted conformational changes that cou ple proton translocation to the synthesis of the high levels of ATP re quired for cellular function. In the structure of the rat liver F-1-AT Pase, determined to 2.8-Angstrom resolution in the presence of physiol ogical concentrations of nucleotides, all three beta subunits contain bound nucleotide and adopt similar conformations. This structure provi des the missing configuration of F-1 necessary to define all intermedi ates in the reaction pathway. Incorporation of this structure suggests a mechanism of ATP synthesis/hydrolysis in which configurations of th e enzyme with three bound nucleotides play an essential role.