Z,E isomerization of the α‐84 phycoviolobilin chromophore of phycoerythrocyanin from Mastigocladus laminosus investigated by Fourier‐transform infrared difference spectroscopy

FEBS Letters

Siebert, F²  Parbel, A¹  Scheer, H¹  Foerstendorf, H² 

[1] Botanisches Institut der Ludwig-Maximilians-Universität, Menzingerstr. 67, D-80638 München, Germany;Institut für Biophysik und Strahlenbiologie, Albert-Ludwigs-Universität, Albertstr. 23, D-79104 Freiburg, Germany

关键词: FT-IR spectroscopy;    Photoreaction;    Phycobiliprotein;    Phycoerythrocyanin;    Phycoviolobilin;    Phytochrome;   

DOI  :  10.1016/S0014-5793(96)01521-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The photoreaction of the phycoviolobilin (PVB) chromophore-containing part of phycoerythrocyanin (PEC) from Mastigocladus laminosus was investigated by Fourier-transform infrared spectroscopy (FT-IR). Difference spectra between the parent states P566 and P507 were obtained in ¹H₂O and ²H₂O for the first time. The spectra are generally characterised by large changes in the range between 1710 and 1590 cm⁻¹ and by a strong difference band around 1270 cm⁻¹. In order to study the influence on the PVB chromophore upon aggregation, spectra of the α-subunit and the (αβ)₃ trimer are compared, showing distinct differences which may be of relevance for the chromophore-protein and protein-protein interactions. The difference spectra demonstrate many similarities to the spectra recently obtained for the P_r→meta-R_c transition of phytochrome [Foerstendorf et al. (1996) Biochemistry 35, 10793–10799]. In particular, a band around 1710 cm⁻¹, which was tentatively assigned to the C=O stretch of ring D is also observed in the spectra of PEC. It strongly supports this identification and the deduced molecular interpretation on the protonation state of the chromophore.

【 授权许可】

Unknown