Identification of a specific fucoxanthin-chlorophyll protein in the light harvesting complex of photosystem I in the diatom Cyclotella meneghiniana |
| |
Authors: | Thomas Veith Wolfram Weisheit Claudia Büchel |
| |
Institution: | a Institute for Molecular Bio Sciences, Johann Wolfgang Goethe-University, SiesmayerstraBe 70, D-60323 Frankfurt am Main, Germany b Institute of General Botany, Friedrich-Schiller-University Jena, Am Planetarium 1, 07743 Jena, Germany |
| |
Abstract: | Thylakoids of the diatom Cyclotella meneghiniana were separated by discontinuous gradient centrifugation into photosystem (PS) I, PSII, and fucoxanthin-chlorophyll protein (FCP) fractions. FCPs are homologue to light harvesting complexes of higher plants with similar function in e.g. brown algae and diatoms. Still, it is unclear if FCP complexes are specifically associated with either PSI or PSII, or if FCP complexes function as one antenna for both photosystems. However, a trimeric FCP complex, FCPa, and a higher FCP oligomer, FCPb, have been described for C. meneghiniana, already. In this study, biochemical and spectroscopical evidences are provided that reveal a different subset of associated Fcp polypeptides within the isolated photosystem complexes. Whereas the PSII associated Fcp antenna resembles FCPa since it contains Fcp2 and Fcp6, at least three different Fcp polypeptides are associated with PSI. By re-solubilisation and a further purification step Fcp polypeptides were partially removed from PSI and both fractions were analysed again by biochemical and spectroscopical means, as well as by HPLC. Thereby a protein related to Fcp4 and a so far undescribed 17 kDa Fcp were found to be strongly coupled to PSI, whereas presumably Fcp5, a subunit of the FCPb complex, is only loosely bound to the PSI core. Thus, an association of FCPb and PSI is assumed. |
| |
Keywords: | Chl chlorophyll DD diadinoxanthin DDM n-dodecyl β-D-maltoside DT diatoxanthin FCP fucoxanthin-chlorophyll protein complexes Fcp fucoxanthin-chlorophyll protein HG β-heptyl glucopyranoside HPLC high pressure liquid chromatography IEX ion exchange chromatography LC-ESI-MS liquid chromatography-electrospray ionisation-mass spectrometry LHC light harvesting complex NG n-nonyl β-D-glucopyranoside OG n-octyl β-D-glucopyranoside PS photosystem SDS-PAGE sodium dodecyl sulphate-polyacrylamide gel electrophoresis TX Triton X-100 |
本文献已被 ScienceDirect 等数据库收录! |
|