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THE MULTIPLE PIGMENT‐PROTEINS OF THE PHOTOSYSTEM I ANTENNA *
Author(s) -
Preiss Susanne,
Peter Gary F.,
Anandan Shivanthi,
Thornber J. Philip
Publication year - 1993
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1993.tb02271.x
Subject(s) - chemistry , photosystem i , photosystem , photosystem ii , pigment , chlorophyll , chlorophyll a , photosynthetic reaction centre , light harvesting complex , biochemistry , photosynthesis , chromatography , organic chemistry
Abstract A photosystem I (PS I) holocomplex was obtained from barley by ultracentrifugation of PS I‐enriched stroma lamellae on sucrose gradients. Further solubilization with glycosidic surfactants followed by Deriphat‐poly‐acrylamide gel electrophoresis (PAGE) fractionated the holocomplex into its core complex (CC I) and individual light‐harvesting I (LHC I) pigment‐protein subcomplexes. The LHC I contains chlorophyll a , all of the chlorophyll A of PS I and xanthophylls but no carotenes. Sodium dodecylsulfate PAGE analysis of the subcomplexes shows that barley LHC I is composed of at least five apoproteins having sizes between 11 and 24 kDa. Isolation of a 17 kDa LHC Ic component by Deriphat‐PAGE shows it to be a photosynthetic pigment‐protein. Room‐temperature absorption spectra indicate that LHC Ic is enriched in chlorophyll a in comparison to the LHC I a and I b components. The LHC Ic apoprotein is shown to be distinct from the subunit III and IV polypeptides of CC I. Analysis of PS I fractions obtained from sucrose gradients as well as from Deriphat‐PAGE indicates that in higher plants an oligomeric structure of the PS I entity exists in vitro.