oa Editorial [Hot Topic: Intra- and Intermolecular Communications in Proteins (Guest Editor: Pier G. De Benedetti)]

Information is going to replace matter and energy as the primary stuff of the universe [1]. Information will provide a new basic unifying conceptual framework for describing and predicting physical events and reality in the 21st century [1]. However biological matter, from atomistic-molecular level to organ-organism level, constitutes the most sophisticated multiscale (in space and time) media in which information is codified, stored and communicated according to multilevel networks of interacting dynamical systems (biological information processing). Two of the most outstanding achievements of 20th century were the invention of computers and the birth of molecular biology. The advances made in these two fields over the past three decades have resulted not only in the generation of vast amounts of data and information, but also in a new understanding of the concept of information itself. Furthermore, modern science is unraveling the nature of information in numerous areas such as communication theory, biology, neuroscience, cognitive science, and biosemiotics, among others. Concurrently, computer based representations, simulations, modeling, and model-based reasoning are gaining in importance as a consequence of the increasing availability of computer power and sophisticated software for any kind of elaboration. In the concept of simulation as a model-based computational activity, the emphasis is on the generation and prediction of model behavior. Hence, simulation can be viewed as model-based knowledge-generation (computational experiments). Thus, simulation can be combined with other types of knowledge-generation techniques such as statistical elaboration, hypothesisprocessing and quantitative networks modeling with the aim of integrating the astonishing amount of the available biological data in a systems biology perspective. In the 20th century biologists successfully explained key functions and processes essential to the functioning of living beings, in terms of physical and chemical mechanisms ultimately driven by thermodynamic laws. These laws can be considered as universal constraints on the behavior of everything existing in the natural world. These restrictions are governed by two facts: in all natural processes energy is conserved and continuously degraded through the irreversible increase of entropy. The concepts and experimental methods of biochemistry and molecular biology succeeded in disclosing, in particular, numerous pathways and complex chains of chemical reactions involved in the metabolism and growth of cells and organisms. Many structural sequences of biomolecules have been mapped out in astonishing detail and have contributed to the relevant advances of current medicine and pharmacology. The main protagonists in these complicated series of events are the proteins. From a fixed repertoire of 20 amino acids, cells can manufacture an unlimited variety of proteins, with radically different shapes and properties, which govern molecular communication and information transfer. In this respect, the following definition of information due to von Baeyer [1] is particularly appropriate: “the word information derives from the Latin Informare (in+formare), meaning to give form, shape, or character to. It is therefore to be the formative principle of or to imbue with some specific character or quality”.