Open AccessReversible membrane association of dinitrogenase reductase activating glycohydrolase in the regulation of nitrogenase activity in Rhodospirillum rubrum ; dependence on GlnJ and AmtB1
Author(s) -
Wang He,
Franke Claudia C.,
Nordlund Stefan,
Norén Agneta
Publication year - 2005
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1016/j.femsle.2005.09.049
Subject(s) - rhodospirillum rubrum , nitrogenase , chemistry , biochemistry , biology , microbiology and biotechnology , biophysics , enzyme , bacteria , nitrogen fixation , genetics
In the photosynthetic bacterium Rhodospirillum rubrum nitrogenase activity is regulated by reversible ADP‐ribosylation of dinitrogenase reductase in response to external so called “switch‐off” effectors. Activation of the modified, inactive form is catalyzed by dinitrogenase reductase activating glycohydrolase (DRAG) which removes the ADP‐ribose moiety. This study addresses the signal transduction between external effectors and DRAG. R. rubrum , wild‐type and P II mutant strains, were studied with respect to DRAG localization. We conclude that GlnJ clearly has an effect on the association of DRAG to the membrane in agreement with the effect on regulation of nitrogenase activity. Furthermore, we have generated a R. rubrum mutant lacking the putative ammonium transporter AmtB1 which was shown not to respond to “switch‐off” effectors; no loss of nitrogenase activity and no ADP‐ribosylation. Interestingly, DRAG was mainly localized to the cytosol in this mutant. Overall the results support our model in which association to the membrane is part of the mechanism regulating DRAG activity.