Foerstendorf H, Parbel A, Scheer H, Siebert F
Institut für Biophysik und Strahlenbiologie, Albert-Ludwigs-Universität, Freiburg, Germany.
FEBS Lett. 1997 Feb 3;402(2-3):173-6. doi: 10.1016/s0014-5793(96)01521-9.
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 alpha-subunit and the (alphabeta)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 Pr --> meta-Rc 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.
利用傅里叶变换红外光谱（FT-IR）研究了来自层理鞭枝藻（Mastigocladus laminosus）的藻红青蛋白（PEC）中含藻紫胆素（PVB）发色团部分的光反应。首次在(^{1}H_{2}O)和(^{2}H_{2}O)中获得了母体状态P566和P507之间的差异光谱。这些光谱的一般特征是在1710至1590(cm^{-1})范围内有较大变化，并且在1270(cm^{-1})左右有一个强差异带。为了研究聚集对PVB发色团的影响，比较了α亚基和（αβ）3三聚体的光谱，结果显示出明显差异，这可能与发色团 - 蛋白质和蛋白质 - 蛋白质相互作用有关。这些差异光谱与最近获得的光敏色素从Pr态到间型Rc态转变的光谱[Foerstendorf等人（1996年）《生物化学》35卷，10793 - 10799页]有许多相似之处。特别是，在PEC的光谱中也观察到了一个约1710(cm^{-1})的带，该带初步被指定为环D的C = O伸缩振动。这有力地支持了这一归属以及对发色团质子化状态的推导分子解释。
