New trends in photobiology

摘要: Abstract Naturally occurring photoreceptors usually contain low-molecular-weight photochromic molecules bound to a macromolecular matrix, such as membrane protein. On irradiation, the moieties undergo reversible stereochemical rearrangements which, in turn, induce structural changes matrix. This paper reports behaviour of synthetic polypeptides which respond light giving rise variations their conformation, similar photosensitive systems nature. Some examples are described detail. Poly( l -glutamic acid) containing 20 mol.% azobenzene units side-chains adopts random coil conformation micellar solution. Irradiation at 350 nm produces → helix transition is completely reversed by irradiation 450 nm. In analogous conditions, azo-modified poly( -lysine) undergoes β-structureαα-helix transition. spiropyran hexafluoro-2-propanol. Exposure sunlight for few seconds causes spiralization polypeptide chains, dark adaptation. The mechanisms photoresponse effects discussed and analogies with biological indicated.