Aggregation behavior of Dabsylated Amino Acids in Aqueous Solution

• Published in: Bunseki kagaku Vol. 54; no. 9; pp. 799 - 805
• Main Authors: HAYASHI, Hiroshige, SASAKI, Chizuru, KUNIMOTO, Ko-Ki, MAEDA, Shiro, HOSOI, Shinzo, KUWAE, Akio, HANAI, Kazuhiko
• Format: Journal Article
• Language: English
• Published: Tokyo Japan Science and Technology Agency 01.09.2005
• ISSN: 0525-1931
• DOI: 10.2116/bunsekikagaku.54.799

A series of dabsylated amino acids (Dabs-AA) were prepared and their aggregation behavior in aqueous solution was studied by UV/Vis absorption and CD spectroscopies. Dabs-AAs show pH-dependent absorption in the visible region, characteristic of the dimethylamio azobenzene chromophore in a dilute aqueous solution. Upon increasing the concentration of Dabs-AAs, the visible absorption around 500 nm of the Dabs-AA monomer decreased its intensity, and a new band due to the Dabs-AA dimer appeared in the 360∼400 nm region. Dimer formation depended on the DMSO co-solvent concentration, the solution temperature and the R-groups of amino acids. A split-type induced CD spectrum was observed for the dimer absorption band of Dabs-L-Phe at 363 nm: a negative first Cotton effect at 379 nm and a positive second Cotton effect at 359 nm. These results indicate that a pair of Dabs-L-Phe molecules were stacked with negative exciton chirality.