Ion-Motive ATPases: Structure, Function, and Regulation [antikvár]

A. SCARPA Department of Physiology and Biophysics Case Western Reserve University School of Medicine 10900 Euclid Avenue Cleveland, Ohio 44106-4970 ERNESTO CARAFOLI Department of Biochemistry ETH 16 Universität Strasse Zurich, Switzerland SERGIO PAPA Institute of Medical Biochemistry and Chemistry University of Bari Piazza G. Cesare 70124 Bari, Italy This volume of the Annals of the New York Academy of Sciences contains recent work on the structure, function, and regulation of ion-motive ATPases presented in Cleveland, Ohio in June 1992 by approximately one hundred scientists. Ion-motive ATPases are widely distributed enzymes within cells and subcellular organelles. In the forward mode, they utilize "chemical energy" in the form of ATP to build ionic gradients, another form of cellular energy storage. Other ATPases, in mitochondria or chloroplasts, work in the reverse or "synthetase" mode and use ionic gradients to synthesize most of the cellular ATP. This transformation of chemical energy into the energy of ionic gradients, and vice versa, is a common and continuous process in eukaryotic, prokaryotic, and plant cells and is the key to cell responses such as excitability, contractility, and secretion. The amount of ATP consumed and synthesized in our body by these ion-motive ATPases is mind-boggling: over 200 pounds of ATP per day are recycled. Ten years ago, two of us organized a conference for the New York Academy of Sciences with a similar focus and title.^ The goal then was to bring together colleagues working on the Na+-K+ ATPase, ATPases, and the H+ ATPases of the fungal plasma membrane. However, at the conference two newly discovered ATPases, the vacuolar ATPase and the Ca2+ ATPase of the plasma membrane, were presented and discussed. It was an exciting and timely meeting, and yet not a single complete sequence of an ATPase was available and the mechanisms of catalysis and regulation of these enzymes were still nebulous. During the last ten years, progress in this field has been enormous: the amino acid sequences of several ATPases have been published; isozymes have been found for most of them; some three-dimensional structural insights have been provided by X-ray or low angle difl'raction; some mechanistic information has been inferred by