Paired moving charges in mitochondrial energy coupling. II. Universality of the principles for energy coupling in biological systems.

Abstract

The thesis is developed that an acceptable model of biological energy coupling must have universal application. The paired moving charge model of mitochondrial energy coupling is examined from the standpoint of this thesis. Fundamental to this model is the notion that energy coupling involves interaction between paired uncompensated charged species in two vectorially aligned and spatially separated reaction centers. The two charge-separating devices are assumed to be the electron transfer chain (in chloroplast and mitochondria) and intrinsic ionophores (in all transducing organelles and kinases). The universality of the ionophore principle becomes then the crucial test of the validity of the paired moving charge model. The multiple facets of ionophoremediated coupled processes are explored, e.g., coupled hydrolysis of ATP, hormonal control of ion movements, and active transport.The design and performance of living systems reflect to a profound degree two sets of principles-the principles of heredity and the principles of energy. The double helix principle of nucleic acid construction enunciated by Watson and Crick two decades ago (1) has been shown by overwhelming evidence to apply across the board to the hereditary process in all types of cells and in all forms of life. Moreover, all the events and systems that translate the hereditary process reflect with great fidelity both the centrality and the uniqueness of the double helix principle. The systems that execute replication (ribosomes, messenger RNA, transfer RNA, chromosomes, and the mitotic apparatus) and that control replication (genes, cistrons, and operons) are in fact molecular devices for the precise translation of the double helix principle. The point to be made is that, given a universal principle of heredity, then all the agents, systems, and tactics that underlie the execution of this principle must also be universal in nature. The ribosome and transfer RNA are two such examples in the structural domain. The mechanisms of protein and nucleic acid synthesis are examples in the functional domain. The universality of the genetic code is an example in the domain of molecular strategy.We have considered elsewhere the compelling nature of the case for the proposition that the principles of energy, like those of heredity, must be universal in character in biological systems (2, 3). We shall restrict our treatment of energy to the molecular tactics by which two processes are coupled one to another. Energy coupling subtends the most crucial aspects of energy in biological systems, and in our view, the understanding of all other aspects of energy, such as catalysis, is derivative from the fundamental principles of energy coupling. In the previous communication of this series, we have proposed and developed a model for mitochondrial energy coupling (4). Since the principles that underlie the model were arrived at by the fitting of theory and experiment, the ability of the model to rationalize mitochondrial energy coupling is in large measure a reflect...