scholarly journals Borate inhibits activation of inactive dinitrogenase reductase from Rhodospirillum rubrum

1981 ◽  
Vol 197 (2) ◽  
pp. 503-505 ◽  
Author(s):  
Paul W. Ludden
Keyword(s):  
Rhodospirillum Rubrum ◽  
Ph Dependence ◽  
Active Form ◽  
Aminophenylboronic Acid ◽  
Dinitrogenase Reductase ◽  
Hydroxy Groups

Borate and aminophenylboronic acid were tested as inhibitors of activation of inactive dinitrogenase reductase from Rhodospirillum rubrum. Inhibition was specific for activation because activity of the active form of the enzyme was not inhibited. Inhibition showed the pH-dependence expected if borate inhibits by binding to cis-hydroxy groups of the modifying group found on the inactive enzyme.

Expression of bacterial Rubisco genes in Escherichia coli

1986 ◽  
Vol 313 (1162) ◽  
pp. 433-445 ◽  
Keyword(s):  
Escherichia Coli ◽  
Rhodospirillum Rubrum ◽  
Active Form ◽  
Amino Acid Residues ◽  
Structural Genes ◽  
Physico Chemical ◽  
Chemical Studies ◽  
The Individual ◽  
Very High

The structural genes for three forms of Rubisco have been isolated from bacteria and introduced into various plasmids. Apart from details of the sequences which have been obtained from these constructs, they are now being exploited for mutagenesis to determine the identity and specific function of the individual amino acid residues that compose the active site. These methods have been applied to a plasmid that contains the structural gene for the simplest form of Rubisco from Rhodospirillum rubrum to obtain mutant enzymes with altered activity. The construct pRR2119 is also expressed to very high levels in Escherichia coli and enough recombinant protein of both the wild-type and m utant enzymes can be obtained for detailed physico-chemical studies. Other vectors have now been constructed, containing the genes of prokaryotic Rubisco that assemble into an active form I enzyme. The levels of expression are acceptable and the product is similar to the authentic enzyme. These constructs are now being used for mutagenesis in vitro to attempt to alter the relative rates of the oxygenase and carboxylase activities.

scholarly journals Comparison of active and inactive forms of iron protein from Rhodospirillum rubrum

1982 ◽  
Vol 203 (3) ◽  
pp. 663-668 ◽  
Author(s):  
P W Ludden ◽  
G G Preston ◽  
T E Dowling
Keyword(s):  
Rhodospirillum Rubrum ◽  
Polyacrylamide Gel Electrophoresis ◽  
Active Form ◽  
Sodium Dodecyl ◽  
Cross Reactivity ◽  
Iron Protein ◽  
Fe Protein ◽  
Inactive Form ◽  
Single Subunit ◽  
Forms Of Iron

The Fe protein of nitrogenase from Rhodospirillum rubrum was purified in its active and inactive forms. It is shown that the inactive form exists as a two-subunit modified form of the enzyme as previously reported [Ludden & Burris (1978) Biochem. J. 175, 251-259]. In contrast, the active form exists as a single-subunit unmodified form of the enzyme. The upper subunit (on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis) of the inactive form was shown to contain at least the phosphate group of the covalently bound modifying group. The active and inactive forms of the enzyme were shown to be identical proteins on the basis of amino-acid composition, tryptic-digest pattern and immunological cross-reactivity.

scholarly journals Correlation of Activity Regulation and Substrate Recognition of the ADP-Ribosyltransferase That Regulates Nitrogenase Activity in Rhodospirillum rubrum

1999 ◽  
Vol 181 (5) ◽  
pp. 1698-1702 ◽  
Author(s):  
Kitai Kim ◽  
Yaoping Zhang ◽  
Gary P. Roberts
Keyword(s):  
Rhodospirillum Rubrum ◽  
Nitrogenase Activity ◽  
Substrate Recognition ◽  
Posttranslational Regulation ◽  
Activity Regulation ◽  
Adp Ribosylation ◽  
Dinitrogenase Reductase ◽  
Adp Ribosyltransferase

ABSTRACT In Rhodospirillum rubrum, nitrogenase activity is regulated posttranslationally through the ADP-ribosylation of dinitrogenase reductase by dinitrogenase reductase ADP-ribosyltransferase (DRAT). Several DRAT variants that are altered both in the posttranslational regulation of DRAT activity and in the ability to recognize variants of dinitrogenase reductase have been found. This correlation suggests that these two properties are biochemically connected.

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