Multiscale Bioengeenering of Ice Controlling Proteins

In nature many life forms are able to survive in drastic environmental conditions, like extremely cold temperatures or very high pressures. Among these are fungi, bacteria and plants that are able to control the ice formation of the surrounding water. This ability allows such organisms to adapt to environmental changes, like large temperatures excursions, and to facilitate the search for food. Many of these organisms are known to contain bio-molecules such as antifreeze proteins (AFPs) and ice nucleator proteins (INPs), capable to influence the ice nucleation rate. Such a feature attracts great interest from a wide spectrum of scientific disciplines like biology and atmospheric science, and it offers several technological applications like cryo-preservation of tissues and increasing frozen food shelf life. The temperaturepressure conditions surrounding an organism naturally select which protein is suitable for that living being. There are ample evidences indicating that the properties of the protein and of the water surrounding it are strongly connected. Here we propose a computational project named Theoretical and Numerical Analysis of Antifreeze and Ice Nucleator Proteins: Coarse-Grain Approach for Multi-scale Study and Bio-Engineering, whose focus lies in studying the mutual water-protein influence for a wide range of temperature and pressure, with a special focus on the behaviour of AFPs and INPs at low temperature. The proposed project aims at studying how the folding and structural properties of AFPs and INPs affect the water properties. This project is based on the combination of two models, one for water and the other for proteins, that have been widely proven and which results have been published on high impact journals like Proceeding of National Academy of Sciences and Physical Review Letters. These models incorporates the main features of water and protein and are able to reproduce their dynamical, thermodynamical and structural properties. The success of this project will pave the way for the computer based design of artificial functionalized protein sequences capable of influencing the phase of water. This project follows an innovative research line that combines multiple fields of research, such as physics, biology and chemistry. This research, due to its interdisciplinary character and broad interest, has large impact on the scientific community and is often the subject of publications in relevant international scientific journals. The project will carried out by the applicant Dr. Valentino Bianco, in collaboration with Dr. Coluzza, expert in modeling and simulations of biophysical systems, and with Prof. Dellago, a world leading expert in statistical physics and computer science, at the physics department of the University Vienna, ranked among the best 150 faculties worldwide.

Many living organisms, via natural selection, have been able to adopt and survive to severe environmental conditions, like extremely cold temperatures or very high pressures. It is the case, for example, of fungi, bacteria and plants that are able to control the ice formation of the surrounding water. This ability allows such organisms to adapt to environmental changes, like large temperatures excursions, and to facilitate the search for food. Many of these organisms are known to contain bio-molecules such as antifreeze proteins (AFPs) and ice nucleator proteins (INPs), capable to influence the ice nucleation rate. Such a feature attracts great interest from a wide spectrum of scientific disciplines like biology and atmospheric science, and it offers several technological applications like cryo-preservation of tissues and increasing frozen food shelf life. The selection of stable protein sequences, capable to fold into a unique stable and functional structure, depends on the temperaturepressure conditions surrounding the organism. There are ample evidences indicating that the properties of protein and water surrounding it are strongly connected, and the water-protein interplay is a fundamental key to understand the selection, the folding and the function of proteins. The proposed project was focusing on the study of the mutual water-protein influence for a wide range of temperature and pressure, with a special focus on the behavior of protein working in extreme conditions like the AFPs. By using computational models, we have developed a strategy to identify protein sequences capable to fold in different thermodynamic conditions, like low temperature or high pressure. We have shown that the sequences of the proteins depend on the water properties and on the environmental conditions where the protein is supposed to work. In particular, the composition of hydrophilic and hydrophobic amino acids depends on the temperature where the protein is supposed to work. Moreover, we have developed general criteria that allow to design artificial heteropolymer and proteins, establishing the minimum number of amino acids necessary to have a folding sequence and their relation with the structure of the folded protein. Finally, we have explored the possibility to enhance the folding of polymers by means of the active monomers along the chains. Our methodology represents the first step toward the design of artificial smart polymers according to the solvent property.