SENSITIZER-INDUCED CONFORMATIONAL CHANGES IN LENS CRYSTALLIN—II. PHOTODYNAMIC ACTION OF RIBOFLAVIN ON BOVINE α-CRYSTALLIN |
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Authors: | Swapan K.,Bose &dagger ,Krishnagopal,Mandal Bireswar,Chakrabarti |
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Affiliation: | Eye Research Institute of Retina Foundation, Boston, MA 02114, USA |
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Abstract: | Abstract— Photolysis of α-crystallin in the presence of riboflavin under both aerobic and anaerobic conditions causes a rapid decrease in Trp emission; photooxidation most likely occurs via non-covalent complex formation between the sensitizer molecule and the substrate. However, the change in the tertiary structure of the protein, as manifested in the near-UV CD, is very different between aerobic and anaerobic photolysis. Riboflavin-sensitized reaction under aerobic condition causes a major change in the microenvironments of thiol groups as well as in the near-UV CD, whereas under anaerobic condition the change in the near-UV CD is much less and SH-group environments remain unaltered. The sensitizer in this photoinduced change in conformation of the protein is very selective and specific. |
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