Molecular recognition of nucleic acids and proteins is of fundamental importance for life. Small molecules selectively targeting specific biomacromolecules are therefore highly interesting not only for understanding of such processes but also for potential medicinal applications, as drugs or probes for bioimaging and analytical purposes. In the last 5 years we developed in collaboration with our partners a series of novel fluorescent amino acids and oligopeptides, which recognised various types of DNA or RNA structures. Also, we showed that non-covalent aggregation of chromophores could be used for DNA/RNA recognition. Very recently we developed fluorescent enzyme inhibitors and novel mitochondria-specific fluorescent markers. In this proposal we want to use large library of fluorophore-amino acids developed in previous CSF project (and prepare new improved ones), as well as our knowledge on dye aggregation, to design and build multichromophore peptides, with variously combined chromophores (e.g. in FRET pairs) and DNA/RNA/protein targeting substituents. Such peptides would serve as multi-purpose probes for the simultaneous sensing (by different spectrometric responses) of several different biomacromolecule secondary structures (e.g. various ds- or ss- DNA/RNA sequences, proteins). Alternatively, peptides will be designed for highly selective interaction with particular bio-target (e.g. particular ds- or ss- DNA, RNA, DPP III enzyme or amyloid-fibrillation peptide sequence). The interaction with DNA/RNA/proteins will be studied by UV/Vis, fluorescence, CD/LD spectroscopy and DSC/ITC microcalorimetry, MS, NMR, CLSM. Proposal addresses the most important CSF goals: a) collaboration with well-established international scientists, b) training of young researchers within the international research environment and c) the expected results have commercialisation potential as novel biochemical probes and/or drugs. Project costs are 994,000.00 HRK for 4 years.