Characterization of photosystem 1 chlorophyll a/b-binding apoprotein accumulation in developing soybean using type-specific antibodies.
The structure and supramolecular assembly of the soybean photosystem 1 (PS 1) chlorophyll a/b-binding antenna (LHC 1) was examined.  We identified the subunit composition of LHC 1 in soybean and followed the accumulation of individual subunits during light-induced assembly.  We observed four LHC 1 subunits, at 23, 22, 21 and 20.5 kDa, obtained partial sequence information by amino-terminal sequence analysis, and classified the 20.5, 22, and 21 kDa subunits as being encoded by type I, II, and IV chlorophyll a/b binding protein genes, respectively.  Antisera against LHC 1 subunits were used to follow the accumulation of individual subunits during the light-initiated transition from etioplast to chloroplast.  Several points are noteworthy.  First, monospecific antibody against the 22 kDa subunit decorated a 25 kDa peptide in etiolated tissue, which declined during maturation.  This decline correlated with the light-induced appearance of mature 22 kDa peptide, suggesting a precursor/product relationship.  Second, the same antibody identified a 22 kDa protein in mature corn, but not a larger band in etiolated corn, suggesting that LHC 1 accumulation is regulated differently between species before the onset of chlorophyll biosynthesis.  Third, the mature 22 kDa subunit appeared somewhat later than the other LHC 1 peptides during greening, implying that this subunit is less intimately associated with the PS1 core than are the subunits appearing earlier in development.
Henry
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RL
Center for Gravitational Studies in Cellular and Developmental Biology, Kansas State University, Manhattan, USA.
Armbrust
T
T
Gallegos
G
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Guikema
J A
JA
D000906:Antibodies; D001059:Apoproteins / Q000032:analysis* / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism; D002734:Chlorophyll / Q000032:analysis / Q000378:metabolism*; D000077194:Chlorophyll A; D004591:Electrophoresis, Polyacrylamide Gel; D007106:Immune Sera; D007425:Intracellular Membranes / Q000737:chemistry / Q000378:metabolism; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry / Q000378:metabolism*; D010860:Pigments, Biological; D013025:Glycine max / Q000737:chemistry* / Q000166:cytology; D003313:Zea mays / Q000737:chemistry / Q000166:cytology
D000906:Antibodies; D001059:Apoproteins; D002352:Carrier Proteins; D007106:Immune Sera; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D010860:Pigments, Biological; D002734:Chlorophyll; C037184:chlorophyll b; D000077194:Chlorophyll A