A) OBJECTIVE No. 2 — The aim of the project is to promote domestic structural chemistry and structural biological research, to support the launch of new cutting-edge basic research and innovation activities by expanding the existing X-ray diffraction infrastructure. The current infrastructure consists of equipped crystallising laboratories, crystallising robot and an outdated diffractometer suitable for protein structure testing. The planned development, the acquisition of a diffractometer with a rotary annode and state-of-the-art hybrid pixel detector, would make it possible to extend the range of applications with the help of a new device with unique sensitivity in Hungary. The importance of X-ray diffraction RESEARCHs — The well-regulated interaction network of molecules plays an unavoidable role in the functioning of the living organism, including the interactions and permanent or transient complexes of proteins with each other and with other molecules. Three-dimensional representation plays a major role in understanding these processes. X-ray diffraction — where the success of the measurement, the information content of the measured data depends both on the quality of the tested crystal and on the state-of-the-art of the diffraction apparatus, is one of the main tools for spatial examination of molecules, molecular complexes and interactions in atomic detail. The Focal Points of RESEARCH — The project brings together interdisciplinary research, focusing on intermolecular interactions, atomic characterisation and design of spatial interaction patterns in protein complexes and small molecule crystals. One of the main objectives of our research is to better understand protein function and loanable protein networks, to map the altered structural-interaction properties of protein variants and protein changes associated with diseases, to help design ligands and proteins (liable peptide motifs). 1) Chemical modification of protein related to diseases (e.g. oxidation is the DJ-1 protein that performs the protective function against Parkinson’s disease; point mutations in the case of an enzyme responsible for the production of pseudouridine involved in fine-tuning of the RNA structure) and understanding of the structural and interaction shifts resulting from these, in order to clarify the structural elements of the function. In addition, our aim is to provide effective assistance in the design of specific ligands (in combination with highly permeable methods) and in the use of advanced ligands as active substance candidates or molecular sensors (e.g. DJ-1 and D-aminoacid oxidase). The diffractometer to be obtained also routinely collects high-quality measurement data from less dispersing crystals, which speeds up the design process. 2) By specific inhibition of the abnormal activation of the immune system, inhibitor molecules that can be used in medicine or in a more detailed examination of activation pathways (e.g. complement system) can be developed. With the X-ray diffraction infrastructure, we want to understand the specificity and selectivity of these new protein inhibitor molecules developed with directional evolution. 3) Between protein-protein interaction patterns, the interactions of node proteins are also significant from a medical point of view, which are characterised by the recognition of various loanable motives, thereby significantly affecting physiological processes by influencing the operation of several protein partners (e.g. S100 proteins involved in metastasis, or MAP kinases, tyrosine kinases that control cell division and motion processes involved in signal transmission processes). The chemical change of protein borrowable surfaces (e.g. phosphorylation) is universal in the regulation of signal transmission processes, often in the background of pathological processes. 4) In the case of self-organised, multimers-generating proteins that separate the chemical reaction they catalyse from the outside world by a cavity system, thus potential targets for biotechnological applications, our aim is to identify and characterise structural details important for protein self-organisation (oligopeptidases). 5) By defining the structure of small molecules, one of our goals is the high precision determination of molecules, from which we can infer the change of reactivity within a series of compounds in the case of biologically active compounds (e.g. ferrocene derivatives, compounds with cytostatic action). 6) Selective, kiral recognition of loanable partners is essential in the functioning of biological systems. In the production of bioactive molecules, therefore, effective separation of mirror image pairs (chiral separation) is of great importance, the most effective method of which is usually the chiral recognition generated by crystallisation in the solid phase. On the other hand, the geometric characteristics of directional interactions and shape fit, which play an important role in chiral recog...