Regulation of nitrogenase by reversible mono-ADP-ribosylation.
Curr Top Microbiol Immunol
; 384: 89-106, 2015.
Article
em En
| MEDLINE
| ID: mdl-24934999
ABSTRACT
Posttranslational modification of proteins plays a key role in the regulation of a plethora of metabolic functions. Protein modification by mono-ADP-ribosylation was first described as a mechanism of action of bacterial toxins. Since these pioneering studies, the number of pathways regulated by ADP-ribosylation in organisms from all domains of life expanded significantly. However, in only a few cases the full regulatory ADP-ribosylation circuit is known. Here, we review the system where mono-ADP-ribosylation regulates the activity of an enzyme the regulation of nitrogenase in bacteria. When the nitrogenase product, ammonium, becomes available, the ADP-ribosyltransferase (DraT) covalently links an ADP-ribose moiety to a specific arginine residue on nitrogenase switching-off nitrogenase activity. After ammonium exhaustion, the ADP-ribosylhydrolase (DraG) removes the modifying group, restoring nitrogenase activity. DraT and DraG activities are reversibly regulated through interaction with PII signaling proteins . Bioinformatics analysis showed that DraT homologs are restricted to a few nitrogen-fixing bacteria while DraG homologs are widespread in Nature. Structural comparisons indicated that bacterial DraG is closely related to Archaea and mammalian ADP-ribosylhydrolases (ARH). In all available structures, the ARH active site consists of a hydrophilic cleft carrying a binuclear Mg(2+) or Mn(2+) cluster, which is critical for catalysis.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Bactérias
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Proteínas de Bactérias
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Adenosina Difosfato Ribose
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Eucariotos
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Nitrogenase
Limite:
Animals
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Humans
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article