The importance of the C-terminal region and Cys residues for the membrane association of the NADPH:protochlorophyllide oxidoreductase in pea.
In vitro chloroplast import reactions and thylakoid association reactions have been performed with a series of C-terminal deletions and Cys-to-Ser substitution mutants of the pea NADPH:protochlorophyllide oxidoreductase (POR; EC 1.6.99). C-terminal deletions of the precursor POR (Delta362-400, Delta338-400, Delta315-400 and Delta300-400) were efficiently translocated across the chloroplast envelope. However, except the Delta396-400 mutant, no C-terminal deletion mutants or Cys-to-Ser substitution (Cys119, Cys281 and Cys309) mutants resisted post-treatment with thermolysin after the thylakoid association reactions. This suggests that these mutants were unable to properly associate to the thylakoids due to changes of the protein conformation of POR.
Aronsson
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Department of Plant Physiology, Göteborg University, P.O. Box 461, SE-405 30 Göteborg, Sweden. har@fysbot.gu.se
Sundqvist
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C
Timko
M P
MP
Dahlin
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C
D001665:Binding Sites; D002462:Cell Membrane / Q000378:metabolism; D003545:Cysteine / Q000235:genetics / Q000378:metabolism*; D016296:Mutagenesis; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D044925:Oxidoreductases Acting on CH-CH Group Donors; D018532:Pisum sativum / Q000201:enzymology; D020524:Thylakoids / Q000378:metabolism
D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; C023886:protochlorophyllide reductase; D003545:Cysteine