THE RESOLUTION ANTI BIOCHEMICAL-CHARACTERIZATION OF SUBCOMPLEXES OF THE MAIN LIGHT-HARVESTING CHLOROPHYLL-A B PROTEIN COMPLEX OF PHOTOSYSTEM-II (LHC-II)/

LHC II isolated from carnation leaves has been solubilized and resolve d by a newly developed, vertical-bed nondenaturing isoelectric focusin g in polyacrylamide slab gels to yield three trimeric subcomplexes foc using at pH 4.52, 4.42 and 4.37 (designated a, b and c, respectively), comprising approximately 38%, 24% and 38% of the chlorophyll. The spe ctroscopic data demonstrated a close similarity among LHC II subcomple xes concerning their chlorophyll content and organization. The most al kaline and the most acidic subcomplex contained the 27 kDa polypeptide of LHC II while the intermediate pi fraction contained both LHC II po lypeptides, i.e. 27 kDa and 26 kDa ones associated at 2:1 stoichiometr y. The 27 kDa polypeptide could be resolved by denaturing isoelectrofo cusing into 10 pI molecular isoforms covering 5.90-4.20 pH range. Thre e of the isoforms were found in the subcomplexes a and b and eight in the subcomplex c. The 26 kDa polypeptide comprised the unique pi molec ular isoform focusing at pH 5.61.