Reversible regulation of the nitrogenase iron protein from Rhodospirillum rubrum by ADP-ribosylation in vitro

Journal Article · Thu May 01 04:00:00 EDT 1986 · J. Bacteriol.; (United States)

OSTI ID:5317025

Lowery, R G; Saari, L L; Ludden, P W

Nitrogenase activity in the photosynthetic bacterium Rhodospirillum rubrum is reversibly regulated by interconversion of the Fe protein between a modified and an unmodified form. Since the discovery of the activation process in 1976, investigators have been unable to demonstrate the inactivation (modification) reaction in vitro. In this study, NAD-dependent modification and concomitant inactivation of the Fe protein were demonstrated in crude extracts of R. rubrum. Activation of the in vitro-modified Fe protein by activating enzyme and structural similarity between the in vivo and in vitro modifications are presented as evidence that the in vitro modification is the physiologically relevant ADP-ribosylation reaction. Using a partially purified preparation, we showed that the inactivating enzyme activity is stimulated by divalent metal ions and ADP, that O/sub 2/-denatured Fe protein will not serve as a substrate, and that dithionite inhibits the modification reaction.

• Research Organization: Univ. of Wisconsin, Madison
• OSTI ID: 5317025
• Journal Information: J. Bacteriol.; (United States), Journal Name: J. Bacteriol.; (United States) Vol. 166:2; ISSN JOBAA
• Country of Publication: United States
• Language: English

Related Subjects

560302* -- Chemicals Metabolism & Toxicology-- Microorganisms-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ADP
BACTERIA
BIOLOGICAL EFFECTS
COENZYMES
ELEMENTS
ENZYME ACTIVITY
ENZYMES
IN VITRO
IRON
METABOLISM
METALS
MICROORGANISMS
NAD
NITRO-GROUP DEHYDROGENASES
NITROGENASE
NUCLEOTIDES
ORGANIC COMPOUNDS
OXIDOREDUCTASES
PROTEINS
RHODOSPIRILLUM
TRANSITION ELEMENTS