Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Borate inhibits activation of inactive dinitrogenase reductase from Rhodospirillum rubrum.

ABSTRACT: 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.

SUBMITTER: Ludden PW

PROVIDER: S-EPMC1163151 | biostudies-other | 1981 Aug

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

Rhodospirillum rubrum possesses a variant of the bchP gene, encoding geranylgeranyl-bacteriopheophytin reductase.

Project description:The bchP gene product of Rhodobacter sphaeroides is responsible for the reduction of the isoprenoid moiety of bacteriochlorophyll (Bchl) from geranylgeraniol (GG) to phytol; here, we show that this enzyme also catalyzes the reduction of the isoprenoid moiety of bacteriopheophytin (Bphe). In contrast, we demonstrate that a newly identified homolog of this gene in Rhodospirillum rubrum encodes an enzyme, GG-Bphe reductase, capable of reducing the isoprenoid moiety of Bphe only. We propose that Rhodospirillum rubrum is a naturally occurring bchP mutant and that an insertion mutation may have been the initial cause of a partial loss of function. Normal BchP function can be restored to Rhodospirillum rubrum, creating a new transconjugant strain possessing Bchl esterified with phytol. We speculate on the requirement of Rhodospirillum rubrum for phytylated Bphe and on a potential link between the absence of LH2 and of phytylated Bchl from the wild-type bacterium. The identification of a second role for the fully functional BchP in catalyzing the synthesis of phytylated Bphe strongly suggests that homologs of this enzyme may be similarly responsible for the synthesis of phytylated pheophytin in organisms possessing photosystem 2. In addition to bchP, other members of a photosynthesis gene cluster were identified in Rhodospirillum rubrum, including a bchG gene, demonstrated to encode a functional Bchl synthetase by complementation of a Rhodobacter sphaeroides mutant.

| S-EPMC134874 | biostudies-literature

Comparison of active and inactive forms of iron protein from Rhodospirillum rubrum.

Project description: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.

| S-EPMC1158281 | biostudies-other