title: Chloroplast phosphoproteins. Phosphorylation of polypeptides of the light-harvesting chlorophyll protein complex.
abstract: When isolated, intact chloroplasts of pea (Pisum sativum) are incubated in the light with [32P]-orthophosphate, isotope is incorporated into several polypeptides. Among the most conspicuous phosphoproteins are two which form a very closely spaced doublet on dodecyl sulphate/polyacrylamide gels and co-electrophorese with the major polypeptide component of the light-harvesting chlorophyll a/b binding complex. Like the light-harvesting polypeptide, the phosphoprotein doublet is bound to thylakoids, sediments with the heavy particles released from thylakoids after digitonin treatment, is soluble in chloroform/methanol and has an apparent molecular weight of about 26 000. The doublet also appears in the highly purified light-harvesting chlorophyll a/b binding complex isolated from thylakoids by hydrosylapatite chromatography. I conclude that two polypeptide components of the complex are phosphorylated. One of these components may be the major light-harvesting chlorophyll a/b binding protein.
mesh_terms: D002734:Chlorophyll / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D008027:Light; D008970:Molecular Weight; D010455:Peptides / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D010788:Photosynthesis; D010944:Plants; D013053:Spectrophotometry
chemical_list: D010455:Peptides; D010750:Phosphoproteins; D002734:Chlorophyll