Selenium increases hydrogenase expression in autotrophically cultured Bradyrhizobium japonicum and is a constituent of the purified enzyme

Boursier, P; Hanus, F. J.; Papen, H.; Becker, Mary Misko; Russell, Sterling A.; Evans, Harold J.

doi:10.1128/jb.170.12.5594-5600.1988

Cited by 19 publications

(4 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It was shown previously that the intracellular free FAD pool increases in this mutant with the external riboflavin concentration and that 6-HDNO activity paralleled this increase (Hinkkanen & Decker, 1982). Similar observations to those described here for flavoenzymes were described for enzymes utilizing trace metals as cofactors (Doyle & Arp, 1986;Iuchi & Lin, 1987;Boursier et al, 1988). Micro-organisms rely on the availability of trace metals from the environment, and an adaptive response correlating enzyme biosynthesis with cofactor supply seems reasonable.…”

Section: Discussionsupporting

confidence: 85%

“…In bacteria, inorganic cofactors co-regulate the expression of their apoenzymes. Thus the synthesis of enzymes containing molybdenum (luchi & Lin, 1987), zinc (Doyle & Arp, 1986) or selenium (Boursier et al, 1988) was shown to be dependent on the supply of the metal ions. Only few data are, however, available on the relationship between the supply of organic cofactors and the biosynthesis of the corresponding apoenzymes.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Riboflavin-dependent expression of flavoenzymes of the nicotine regulon of Arthrobacter oxidans

Brandsch

Bichler

1990

Biochemical Journal

View full text Add to dashboard Cite

In cells of an Arthrobacter oxidans riboflavin-dependent mutant the specific activity of the DL-nicotine-inducible nicregulon enzymes nicotine dehydrogenase (NDH, EC 1.5.99.4), 6-hydroxy-L-nicotine oxidase (6-HLNO, EC 1.5.3.5) and 6-hydroxy-D-nicotine oxidase (6-HDNO, EC 1.5.3.6) was shown to be dependent on the supply of the vitamin in the growth medium. Experiments designed to identify at which level riboflavin directs the biosynthesis of these flavoenzymes revealed that the steady-state levels of enzyme protein analysed on Western blots correlated directly with riboflavin supply from the minimal concentration of 0.5 microns-riboflavin required for growth up to 8 microns-riboflavin. Mutant cells grown at the higher riboflavin concentration showed on dot-blots increased levels of RNA which hybridized to 32P-labelled probes derived from the nic-regulon genes. When cells grown at 2 microns-riboflavin were shifted to 8 microns-riboflavin, 6-HDNO expression increased as indicated by elevated enzyme and RNA levels. When the rates of synthesis of the 6-HDNO and 6-HLNO polypeptides after DL-nicotine induction was analysed in cells grown at 0.5 microns and 8 microns-riboflavin, only cells grown at the higher riboflavin concentration showed on Western blots an accumulation of the polypeptides. No 6-HDNO or 6-HLNO polypeptide was identified in cell extracts from cells grown on 0.5 microns-riboflavin. Pulse-chase experiments with [35S]methionine showed that 6-HDNO- and 6-HLNO synthesis was prevented in cells grown at the low riboflavin concentration. The absence of detectable enzyme levels seemed not to be caused by proteolytic breakdown. Incubation in vitro of apo-6HDNO with low- or high-riboflavin-grown-cell extracts showed no increased proteolytic activity in 0.5 microns-riboflavin-grown cells. From these results it is concluded that riboflavin supply co-regulates the expression of the nicregulon genes at the level of transcription and/or mRNA turnover.

show abstract

Section: Discussionsupporting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Riboflavin-dependent expression of flavoenzymes of the nicotine regulon of Arthrobacter oxidans

Brandsch

Bichler

1990

Biochemical Journal

View full text Add to dashboard Cite

show abstract

“…vanniellii [32]. japonicum grown under autotrophic conditions is increased by the presence of selenite and selenium is found in the purified hydrogenase [125]; however, the nucleotide sequence of the gene for the large subunit does not contain an internal TGA codon and selenocysteine is not present in the purified hydrogenase [42]. japonicum grown under autotrophic conditions is increased by the presence of selenite and selenium is found in the purified hydrogenase [125]; however, the nucleotide sequence of the gene for the large subunit does not contain an internal TGA codon and selenocysteine is not present in the purified hydrogenase [42].…”

mentioning

confidence: 99%

Structure-function relationships among the nickel-containing hydrogenases

Przybyla

1992

FEMS Microbiology Letters

View full text Add to dashboard Cite

The enzymology of the heterodimeric (NiFe) and (NiFeSe) hydrogeneses, the monomeric nickel‐containing hydrogenases plus the multimeric F420‐(NiFe) and NAD+‐(NiFe) hydrogenases are summarized and discussed in terms of subunit localization of the redox‐active nickel and non‐heme iron clusters. It is proposed that nickel is ligated solely by amino acid residues of the large subunit and that the non‐heme iron clusters are ligated by other cysteine‐rich polypeptides encoded in the hydrogenase operons which are not necessarily homologous in either structure or function. Comparison of the hydrogenase operons or putative operons and their hydrogenase genes indicate that the arrangement, number and types of genes in these operons are not conserved among the various types of hydrogenases except for the gene encoding the large subunit. Thus, the presence of the gene for the large subunit is the sole feature common to all known nickel‐containing hydrogenases and unites these hydrogenases into a large but diverse gene family. Although the different genes for the large subunits may possess only nominal general derived amino acid homology, all large subunit genes sequenced to date have the sequence R‐X‐C‐X‐X‐C fully conserved in the amino terminal region of the polypeptide chain and the sequence D‐P‐C‐X‐X‐C fully conserved in the carboxyl terminal region. It is proposed that these conserved motifs of amino acids provide the ligands required for the binding of the redox‐active nickel. The existing EXAFS (Extended X‐ray Absorption Fine Structure) information is summarized and discussed in terms of the numbers and types of ligands to the nickel and the various redox species of nickel defined by EPR spectroscopy. New information concerning the ligands to nickel is presented based on site‐directed mutagenesis of the gene encoding the large subunit of the (NiFe) hydrogenase‐1 of Escherichia coli. Based on considerations of the biochemical, molecular and biophysical information, ligand environments of the nickel in different redox states of the (NiFe) hydrogenase are proposed.

show abstract

“…The H2 uptake hydrogenase from B. japonicum has been purified from vegetative (14,37) and symbiotic (1) cells and shown to contain two polypeptide subunits of approximately 65 and 35 kilodaltons (kDa). Besides FeS clusters, nickel (1,14) and probably selenium (3) are also components of the active hydrogenase. Mutants defective in hydrogenase activity have been generated and used in the isolation of H2 uptake (hup) genes (6,17).…”

mentioning

confidence: 99%

Genetic organization of the hydrogen uptake (hup) cluster from Rhizobium leguminosarum

et al. 1990

View full text Add to dashboard Cite

In symbiosis with peas, Rhizobium leguminosarum UPM791 induces the synthesis et a nydrogen uptake (Hup) system that recycles hydrogen generated in nodules by nitrogenase. A cosmid (pAL618) containing hup genes from this strain on a 20-kilobase-pair (kb) DNA insert has previously been isolated in our laboratory (A. Leyva, J. M. Palacios, T. Mozo, and T. Ruiz-Argueso, J. Bacteriol. 169:4929-4934, 1987). Here we show that cosmid pAL618 contains all of the genetic information required to confer high levels of hydrogenase activity on the naturally Hup-strains R. leguminosarum UML2 and Rhizobium phaseoli CFN42, and we also describe in detail the organization of hup genes on pAL618. To study hup gene organization, site-directed transposon mutagenesis and complementation analysis were carried out. According to the Hup phenotype associated with the transposon insertions, hup genes were found to span a 15-kilobase-pair region within pAL618 insert DNA. Complementation analysis revealed that Hup-mutants fell into six distinct complementation groups that define six transcriptional units, designated regions hupI to hupVl. Region hupl was subcloned and expressed in Escherichia coli cells under the control of a bacteriophage T7 promoter. A polypeptide of ca. 65 kilodaltons that was cross-reactiOe with antiserum against the large subunit of Bradyrhizobium japonicum hydrogenase was detected both in E. coli cells carrying the cloned hupl region and in pea bacteroids from strain UPM791, indicating that region hupl codes for structural genes of R. leguminosarum hydrogenase.

show abstract

Selenium increases hydrogenase expression in autotrophically cultured Bradyrhizobium japonicum and is a constituent of the purified enzyme

Cited by 19 publications

References 30 publications

Riboflavin-dependent expression of flavoenzymes of the nicotine regulon of Arthrobacter oxidans

Riboflavin-dependent expression of flavoenzymes of the nicotine regulon of Arthrobacter oxidans

Structure-function relationships among the nickel-containing hydrogenases

Genetic organization of the hydrogen uptake (hup) cluster from Rhizobium leguminosarum

Contact Info

Product

Resources

About