The work described in this thesis was aimed at the study of the functional properties of (isolated and purified) biomolecular systems at the single-molecule level. Two prerequisites are essential... Show moreThe work described in this thesis was aimed at the study of the functional properties of (isolated and purified) biomolecular systems at the single-molecule level. Two prerequisites are essential for successfully achieving this goal. First of all, single biomolecules should be observable, which means that they should be natively fluorescent or they should be rendered fluorescent by suitable biochemical or biomolecular 12 engineering. The other challenge is to engineer the system in such a way that the fluorescence intensity reports the actual, functional state of the biomolecule. Show less