Circular dichroism and stereochemistry of the phycobilins and their derivatives

✍ Scribed by Lingjiang Cheng; Lijin Jiang

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 720 KB
• Volume: 15
• Category: Article
• ISSN: 1011-1344
• DOI: 10.1016/1011-1344(92)85140-p

✦ Synopsis

The circular dichroism spectra of several phywbilins and their 3,3'-addition derivatives are reported. The patterns of the circular dichroism spectra are dependent on the conjugative helical types of the compounds in solution. For the 3,3'-addition derivatives, the intensities of the Cotton effects are closely dependent on the size of the substituents at C3'. The Cotton effects may be attributed to the intramolecular hydrogen bonding. Since the substituent at C3' is extended in a single direction, the conjugative skeleton exhibits a single helical form when a hydrogen bond is formed between ring D and the 3' substituent, and the solution of the derivative exhibits a strong circular dichroism Cotton effect. Conformational analysis indicates that the main type of helical skeleton produced when an intramolecular hydrogen bond is formed is determined by the configuration of C3'. According to the relationship between the circular dichroism spectra and the configuration of C3', the stereochemistry of the epimeric derivatives can be assigned.