In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 77, No. 9 ( 1980-09), p. 5253-5257
Abstract:
Incubation of isolated chloroplast thylakoid membranes with [gamma-32P]ATP results in phosphorylation of surface-exposed segments of several membrane proteins. The incorporation of 32P is light dependent, is blocked by 3(3,4-dichlorophenyl)-1,1-dimethylurea (diuron, an inhibitor of electron transport), but is insensitive to uncouplers of photophosphorylation. Polypeptides of the light-harvesting chlorophyll a/b-protein complex are the major phosphorylated membrane proteins. Addition of ATP to isolated chloroplast thylakoid membranes at 20 degrees C results in a time-dependent reduction of chlorophyll fluorescence emission; this is blocked by diuron but not by nigericin. ADP could not substitute for ATP. Chlorophyll fluorescence induction transients showed a decrease in the variable component after incubation of the membranes with ATP. Chlorophyll fluorescence at 77 K of phosphorylated thylakoid membranes showed an increase in long-wavelength emission compared with dephosphorylated controls. We conclude that a membrane-bound protein kinase can phosphorylate surface-exposed segments of the light-harvesting pigment-protein complex, altering the properties of its interaction with the two photosystems such that the distribution of absorbed excitation energy increasingly favors photosystem I.
Type of Medium:
Online Resource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.77.9.5253
Language:
English
Publisher:
Proceedings of the National Academy of Sciences
Publication Date:
1980
detail.hit.zdb_id:
209104-5
detail.hit.zdb_id:
1461794-8
SSG:
11
SSG:
12
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