Characterization of chloroplast thylakoid polypeptides in the 32-kDa region: Polypeptide extraction and protein phosphorylation affect binding of photosystem II-directed herbicides

Willem Vermaas, Katherine E. Steinback, Charles J. Arntzen

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Abstract

In order to distinguish between two photosystem II proteins with apparent molecular weights of about 32 kDa, mild extraction procedures were used to remove several thylakoid membrane components. A 32-kDa protein that stained intensely with Coomassie brilliant blue could be extracted from the thylakoid membranes without removing the 32-kDa herbicide receptor protein, which stained poorly with Coomassie brilliant blue. The nonextracted protein was readily detectable after in vivo polypeptide labeling with [35S]methionine or after in vitro covalent tagging with [14C]azidoatrazine. The procedures used to extract the intensely stained, 32-kDa polypeptide resulted in changes in herbicide-binding characteristics, presumably due to conformational changes in the herbicide-binding environment. Alterations of membrane surface charge by protein phosphorylation also influenced herbicide binding.

Original languageEnglish (US)
Pages (from-to)226-232
Number of pages7
JournalArchives of Biochemistry and Biophysics
Volume231
Issue number1
DOIs
Publication statusPublished - May 15 1984
Externally publishedYes

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