Purification and
Characterization of the Antenna Protein CP29 from Spinach Photosystem II
LI Xiao-Peng, DU Lin-Fang and LIANG Hou-Guo
( Department of Biology, Sichuan University, Chengdu 610064, China
)
Abstract A Chl a/b-binding
protein, CP29, was purified from PS II core complex of spinach by
DEAE-Toyopearl-650S anion-exchange chromatography, after treatment with the
mild nonionic detergentβ-dodecyl maltoside and high concentration of LiClO4.
At room temperature, purified CP29 had a maximum absorption at 677 nm and a
fluorescence maximum at 681 nm and doublet CD signals which indicated the
presence of excitonic interactions between chlorophylls. The pigment content of
the CP29 was 5�D7 Chl a molecules and 2�D3 Chl b molecules per
CP29 polypeptide, which was determined by spectroscopic method. These results
suggested that the purified CP29 was in a native state. The conformational
contents of CP29 were analyzed with the help of the room temperature CD spectra
of CP29. The secondary structure of CP29 was predicted by using Chou-Fasman
method.
Key Words photosystem II； CP29； spectrum characteristic； circular dichroism； secondary structure
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