Isolation of the Main Light-harvesting Chlorophyll a/b-protein Complex from Thylakoid Membranes of Marine Alga, Bryopsis corticulans by a Direct Method

摘要

The main chlorophyll a/b light-harvesting complex (LHC II) has been isolated directly from thylakoid membranes of marine green alga (Bryopsis corticulans Setch.) by two consecutive runs of anion exchange and gel-filtration chromatography. LHC II proteins in the membrane extracts treated with 3% n-Octyl-b-D-glucopyranoside (OG) obtained specific binding ability on Q Sepharose column, and thus were isolated from the thylakoid membranes in a highly selective fraction. The monomeric, trimeric and oligomeric subcomplexes of LHC II have been obtained by fractionation of the LHC II mixes with sucrose density gradient ultracentrifugation. The SDS-PAGE analysis of peptide composition and absorption spectrum showed that LHC II monomers, trimers and oligomers prepared through this work were intact and in high purity. Our report is the first to show that it is possible to purify LHC II directly from thylakoid membranes without extensively biochemical purification.