The Photochemistry of Nucleic Acids Photosensitised Reactions of DNA: Cleavage and Addition Photoreactions of Nucleic Acids and their Constituents with Amino Acids and Related Compounds Applications of Psoralens as Probes of Nucleic Acid Structure and Function 4-Thiouridine as an Intrinsic Photaffinity Probe of Nucleic Acid Structure and Interactions.