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Most studies on proteins have centered on the conformation and stability of the folded state. The unfolded state has essentially been neglected because of its reputation of being devoid of biological function, and not well-defined. Recently the importance of unfolded segments, as part of the secondary structure of globular proteins and their role in the performance of biological functions, has become apparent. We also are beginning to realize that there may be a surprising simplicity to what previously appeared to be a heterogeneous disorder. Thus the unfolded state can be characterized as having, in part, the same conformation as that adopted by a single polypeptide chain of the collagen molecule, termed the polyproline II (PPII) conformation. This PPII conformation has emerged as an important member in both the globular protein secondary structure and the unfolded state. Additionally, the important role of water in the stabilization of this conformation is crucial being the major determinant of it This overview compiles recent significant findings on the unfolded state and highlights the essential role of water to its structure. Furthermore, we extend these findings to suggest a possible mechanism on the structuring of water by the antifreeze glycoproteins

Interfacial water is the water moiety in a living cell located in the immediate vicinity of particulate cell components of any kind, of which most will be proteins and membranes. It is often called vicinal water. According to theoretical considerations and experimental findings, interfacial water exhibits structural organizations that differ from ‘free’, i.e. ‘bulk’ water. These specific structural properties may be influenced by structural properties of the cellular particulate components. The deviation of vicinal/interfacial water from that of ‘free’ water implies, but does not necessarily ensure, that functional differences exist between them. Hence, there exists a range of mutual interdependences of the properties of the particulate cell components regarding the potential for structuring of water, water structure, the functional properties of interfacial water, and the physiologically important properties of the particulate cell components surrounded by interfacial water. In this communication, simulated examples are described that illustrate some of the possible consequences of these mutual interdependences for the architecture and function of prokaryotic and eukaryotic cells at the cellular and macromolecular levels, which may not be trivial. In addition, examples typical for the structural organization of prokaryotic and eukaryotic cells are described that support the notion of mutual interdependences

Donnan potentials have been measured in polyelectrolyte hydrogels gels of poly(methacr-ylic acid) and their potassium salts in water, using Ag/AgCl microelectrodes at 298 K. The Donnan potential varied from -80 to -40 mV as a function of gels’ cross-link density and the fraction of potassuim methacrylate monomer units. Negative values of the potential increase with the decrease in cross-link density of the gel. Gels with an increasing fraction of potassium methacrylate yield less negative values. The results are discussed from the viewpoint of the Donnan theory initially developed for membrane potential. The theory is qualitatively consistent with observed dependencies of the potential. However several quantitative differences are present, whose sources are analyzed

Water actively participates in bioenergetics and bioregulation. It is essential for purposeful production of reactive oxygen species (ROS) in cells and extracellular matrix. Due to specific structuring of water it itself may serve the source of free radicals and initiate reactions with their participation. On the other hand water structuring provides for its direct oxidation with oxygen. Processes going on in aqueous systems in which ROS participate are the sources of high grade energy of electronic excitation which is not easily and uselessly dissipated in aqueous milieu of living systems but rather can be accumulated, concentrated, and used as energy of activation for the performance of biochemical reactions. Such processes spontaneously acquire oscillatory character and may serve as pacemakers for biochemical reactions dependent on them. Thus due to its unique structural-dynamic properties water may serve as a transformer of energy from low density to high density form, may accumulate the former and use it for organization and support of vital activity

A description is presented of the research on recently observed phenomenon that we call ‘‘the autothixotropy of water’’. The phenomenon is very weak on macroscopic scale and it appears only if the water is standing still for a certain time. It causes a force of mechanic resistance against an immersed body, arising when it should change its position. Both static and dynamic methods are used: With a static method a moment of force, necessary for a very prominent turn of a stainless steel plate, hung up on a thin filament and immersed in standing water, is measured. With a given angular torsion of the filament, a certain moment of force is reached a (state of stress reaches a critical value) in the water, which is demonstrated by impressive changing of angular position of the plate. When a dynamic methods were used, both oscillations of the plate and a very slow fall of a small ball in standing water were observed. The autothixotropy of water can be explained by a hypothesis of cluster formation by H_2O molecules in standing water. As the phenomenon of autothixotropy does not appear in deionized water, a conclusion can be preliminary drawn, that the phenomenon is determined by a presence of ions in the water

Given that a major fraction of cellular water is non-bulk-like in its physical properties the question arises: What is the molecular basis of this non-bulk water? As proteins are, by mass, the major solute in the cell it is natural to suspect proteins as the main factor responsible for the non-bulk properties of water in cells. This report reviews possible theories and facts on the origins of this non-bulk-like cellular water. After review of theories in the literature it is concluded that native globular proteins in their free and polymerized state can account for the major fraction of cell water as being non-bulk-like in its physical properties

Making a brief history of what is named the ‘Memory of Water’ is obviously not an easy task. Trying to be as fair and accurate as possible is hampered by two main difficulties: 1) one of the main actors, Jacques Benveniste, recently passed away and 2) cutting edge science creates many controversies, especially with those whose lifetimes have been spent pursuing an unorthodox track. High dilution experiments and memory water theory may be related, and may provide an explanation for the observed phenomena. As Michel Schiff said: ‘the case of the memory of water may or not contribute to the knowledge about water structure. Perhaps the tentative interpretation Jacques suggested will finally have to be modified or even abandoned. Time and further research will tell, provided that one gives the phenomena a chance (Schiff, 1995, p 45)’

The temporomandibular joint (TMJ) disc is a loaded tissue that is subjected to pressure during virtually every functional movement. To understand the biomechanical properties of the TMJ disc requires a detailed understanding of how water is bound to and organized around the macromolecular components of the disc. Specifically, how much of the water in the disc is unbound to the macromolecular components and free to flow with the same characteristics of bulk water? The combined data from three different methods (flow rate, proton NMR dehydration and freezing point characteristics) lead to the conclusion that all or almost all of the water in the intact TMJ disc is bound water and does not have properties consistent with free or bulk water. Two major non-bulk-like fractions of water were identified and their amounts in g water/g dry mass were determined. The inner water compartment has 1.13–1.30 g water/g dry mass while the outer water compartment has 0.90–0.99 g water/g dry mass. That all three methods yielded similar water compartment values indicate these two water compartments have distinct physical properties