title: Comparison studies of dinitrogenase reductase ADP-ribosyl transferase/dinitrogenase reductase activating glycohydrolase regulatory systems in Rhodospirillum rubrum and Azospirillum brasilense.
abstract: Reversible ADP ribosylation of dinitrogenase reductase, catalyzed by the dinitrogenase reductase ADP-ribosyl transferase (DRAT)/dinitrogenase reductase activating glycohydrolase (DRAG) regulatory system, has been characterized in both Rhodospirillum rubrum and Azospirillum brasilense. Although the general functions of DRAT and DRAG are very similar in these two organisms, there are a number of interesting differences, e.g., in the timing and extent of the regulatory response to different stimuli. In this work, the basis of these differences has been studied by the heterologous expression of either draTG or nifH from A. brasilense in R. rubrum mutants that lack these genes, as well as the expression of draTG from R. rubrum in an A. brasilense draTG mutant. In general, these hybrid strains respond to stimuli in a manner similar to that of the wild-type parent of the recipient strain rather than the wild-type source of the introduced genes. These results suggest that the differences seen in the regulatory response in these organisms are not primarily a result of different properties of DRAT, DRAG, or dinitrogenase reductase. Instead, the differences are likely the result of different signal pathways that regulate DRAG and DRAT activities in these two organisms. Our results also suggest that draT and draG are cotranscribed in A. brasilense.
authors.affiliation: Department of Biochemistry, University of Wisconsin-Madison 53706, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.forename: R H
authors.initials: RH
authors.lastname: Burris
authors.forename: P W
authors.initials: PW
authors.lastname: Ludden
authors.forename: G P
authors.initials: GP
authors.lastname: Roberts
mesh_terms: D036002:ADP Ribose Transferases / Q000096:biosynthesis / Q000235:genetics*; D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D015806:Azospirillum brasilense / Q000201:enzymology / Q000235:genetics* / Q000528:radiation effects; D003624:Darkness; D017037:Dinitrogenase Reductase / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D006026:Glycoside Hydrolases / Q000096:biosynthesis / Q000235:genetics*; D008027:Light; D009699:N-Glycosyl Hydrolases; D009586:Nitrogen Fixation / Q000502:physiology; D009591:Nitrogenase / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology; D012247:Rhodospirillum rubrum / Q000201:enzymology / Q000235:genetics* / Q000528:radiation effects; D013045:Species Specificity; D014158:Transcription, Genetic
chemical_list: D017037:Dinitrogenase Reductase; D000644:Quaternary Ammonium Compounds; D000246:Adenosine Diphosphate Ribose; D009591:Nitrogenase; D036002:ADP Ribose Transferases; C057637:dinitrogenase reductase ADP-ribosyltransferase; D006026:Glycoside Hydrolases; D009699:N-Glycosyl Hydrolases; C036091:ADP-ribosyl-(dinitrogen reductase) hydrolase