Purification and characterization of the antenna protein CP29 from spinach photosystem II

A Chi 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 detergent beta-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 Cp signals which indicated the presence of excitonic interactions between chlorophylls. The pigment content of the CP29 was 5-7 Chi a molecules and 2-3 Ct?; 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.