ORIGIN OF THE RED SHIFTED ABSORPTION IN PHYCOCYANIN 632 FROM Mastigocladus laminosus |
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| Authors: | L Gottschalk R Fischer F Lottspeich H Scheer |
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| Institution: | Botanisches Institut der Universität, Menzinger Str. 67, D-8000 München 19, Germany;Max- Planck-Institut für Biochemie, Am Klopferspitz, D-8033 Martinsried, Germany |
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| Abstract: | A phycocyanin (PC) with γmax= 632 nm (PC632) was isolated from extracts of the cyanobacterium Mastigocladus laminosus. The complex contained three polypeptides migrating in SDS-PAGE around 22 kDa. The N-termini of the three polypeptides are identical. They are homologous to rod-core linker polypeptides from this and another cyanobacterium and are identical to one of them. Reconstitution of PC (γmax=614–620 nm) with the 22 kDa polypeptide produced again the red-shifted PC632. Phycobilisomes isolated at pH 6 or 7 contain, if any, only traces of 22 kDa polypeptides. Origin and functions of the polypeptides are discussed, they are most likely proteolytic fragments of allophycocyanin-PC rod-core linkers that contain the PC-binding domain. |
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