Crystal Structure of the MgA.ADP-inhibited State of the Yeast F1c10-ATP Synthase

The F sub(1)c sub(10) subcomplex of the yeast F sub(1)F sub(0)-ATP synthase includes the membrane rotor part c sub(10)-ring linked to a catalytic head, (ab) sub(3), by a central stalk, gdIek. The Saccharomyces cerevisiae yF sub(1)c sub(10)A.ADP subcomplex was crystallized in the presence of MgA.ADP, dicyclohexylcarbodiimide (DCCD), and azide. The structure was solved by molecular replacement using a high resolution model of the yeast F sub(1) and a bacterial c-ring model with 10 copies of the c-subunit. The structure refined to 3.43-[angst.] resolution displays new features compared with the original yF sub(1)c sub(10) and with the yF sub(1) inhibited by adenylyl imidodiphosphate (AMP-PNP) (yF sub(1)(I-III)). An ADP molecule was bound in both b sub(DP) and b sub(TP) catalytic sites. The a sub(DP)-b sub(DP) pair is slightly open and resembles the novel conformation identified in yF sub(1), whereas the a sub(TP)-b sub(TP) pair is very closed and resembles more a DP pair. yF sub(1)c sub(10)A.ADP provides a model of a new MgA.ADP-inhibited state of the yeast F sub(1). As for the original yF sub(1) and yF sub(1)c sub(10) structures, the foot of the central stalk is rotated by 640 A with respect to bovine structures. The assembly of the F sub(1) central stalk with the F sub(0) c-ring rotor is mainly provided by electrostatic interactions. On the rotor ring, the essential cGlu super(59) carboxylate group is surrounded by hydrophobic residues and is not involved in hydrogen bonding.