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Reversible inhibition of CO 2 fixation by ribulose 1,5‐bisphosphate carboxylase/oxygenase through the synergic effect of arsenite and a monothiol
Author(s) -
SUDHANI HEMANTH P. K.,
GARCíAMURRIA MARíAJESúS,
MORENO JOAQUíN
Publication year - 2013
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12050
Subject(s) - arsenite , ribulose 1,5 bisphosphate , rubisco , pyruvate carboxylase , ribulose , oxygenase , chemistry , biochemistry , glutathione , carbon fixation , photosynthesis , enzyme , arsenic , organic chemistry
The photosynthetic carbon‐fixing enzyme, ribulose 1,5‐bisphosphate carboxylase/oxygenase ( R ubisco), is reversibly inhibited by micromolar arsenite in the presence of an enhancer monothiol such as cysteine, cysteamine, 2‐mercaptoethanol or N ‐acetylcysteine, but not glutathione. Arsenite reacts specifically with the vicinal C ys172‐ C ys192 from the large subunit of Rubisco and with the monothiol to establish a ternary complex. The combination of arsenite and monothiol stops also the carbon fixation in illuminated cultures of C hlamydomonas reinhardtii but the in vivo arrest appears to be driven by an undetermined effector that is even more sensitive to the arsenite‐thiol synergism than R ubisco.