Fourier transform near-infrared resonance Raman spectroscopic study of the α-subunit of phycoerythrocyanin and phycocyanin from the cyanobacterium Mastigocladus laminosus
✍ Scribed by Christa Kneip; Axel Parbel; Harald Foerstendorf; Hugo Scheer; Friedrich Siebert; Peter Hildebrandt
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 287 KB
- Volume
- 29
- Category
- Article
- ISSN
- 0377-0486
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✦ Synopsis
The isolated a-subunits of the light-harvesting pigments phycoerythrocyanin (PEC) and C-phycocyanin (CPC) of Mastigocladus laminosus were studied by resonance Raman (RR) spectroscopy. The results for PEC indicate that the photoconversion of the tetrapyrrole chromophore from the Z,Z to the Z,E conÐguration is associated with structural changes which are largely restricted to the photoisomerization site, i.e. the methine-bridge C-D. Evidently the rotation around this double bond is not complete in the Ðrst intermediate which can be detected after the photochemical event. The subsequent decay to the stable Z,E isomer at T > Ô30 ÄC is associated with conformational relaxations of the remainder of the chromophore. Thus, the PEC photoconversion di †ers substantially from that of the plant photoreceptor phytochrome, which exhibits more extended changes of the chromophore structure and its interactions with the protein environment during the photoconversion.