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Fourier transform near‐infrared resonance Raman spectroscopic study of the α‐subunit of phycoerythrocyanin and phycocyanin from the cyanobacterium Mastigocladus laminosus
Author(s) -
Kneip Christa,
Parbel Axel,
Foerstendorf Harald,
Scheer Hugo,
Siebert Friedrich,
Hildebrandt Peter
Publication year - 1998
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/(sici)1097-4555(199810/11)29:10/11<939::aid-jrs320>3.0.co;2-x
Subject(s) - chromophore , tetrapyrrole , photoisomerization , raman spectroscopy , chemistry , photochemistry , phycocyanin , resonance (particle physics) , resonance raman spectroscopy , infrared , crystallography , stereochemistry , isomerization , optics , cyanobacteria , physics , organic chemistry , biology , bacteria , genetics , particle physics , enzyme , catalysis
The isolated α‐subunits of the light‐harvesting pigmentsphycoerythrocyanin (PEC) and C‐phycocyanin (CPC) of Mastigocladuslaminosus were studied by resonance Raman (RR) spectroscopy. Theresults for PEC indicate that the photoconversion of the tetrapyrrolechromophore from the Z , Z to the Z , E configuration is associated with structural changes which are largelyrestricted to the photoisomerization site, i.e. the methine‐bridgeC–D. Evidently the rotation around this double bond is notcomplete in the first intermediate which can be detected after thephotochemical event. The subsequent decay to the stable Z , E isomer at T >‐30°C is associated withconformational relaxations of the remainder of the chromophore. Thus,the PEC photoconversion differs substantially from that of the plantphotoreceptor phytochrome, which exhibits more extended changes of thechromophore structure and its interactions with the proteinenvironment during the photoconversion. © 1998 John Wiley &Sons, Ltd.