Control of 5-aminolaevulinate synthetase activity in <i>Rhodopseudomonas spheroides</i> a role for trisulphides

Sandy, John D.; Davies, R.C.; Neuberger, A.

doi:10.1042/bj1500245

Cited by 57 publications

(44 citation statements)

References 31 publications

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“…C. however, the HemAl and HemT1 mutants grew slower than the wild type, suggesting more-complex effects of the mutations. In vitro measurements of ALA synthase may also differ from those in vivo, since previous studies have shown that oxidation-reduction states can affect enzyme activation (5,17,27,29,38).…”

Section: Discussionmentioning

confidence: 97%

5-Aminolevulinic acid availability and control of spectral complex formation in hemA and hemT mutants of Rhodobacter sphaeroides

Neidle

Kaplan

1993

J Bacteriol

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In the photosynthetic bacterium Rhodobacter sphaeroides, two genes, hemA and hemT, each encode a distinct 5-aminolevulinic acid (ALA) synthase isozyme (E. L. Neidle and S. Kaplan, J. Bacteriol. 175:2292Bacteriol. 175: -2303Bacteriol. 175: , 1993. This enzyme catalyzes the first and rate-limiting step in a branched pathway for tetrapyrrole formation, leading to the biosynthesis of hemes, bacteriochlorophylls, and corrinoids. In an attempt to determine the functions of hemA and hemT, mutant strains were constructed with specific chromosomal disruptions. These chromosomal disruptions allowed hemA and hemT to be precisely localized on the larger and smaller of two R. sphaeroides chromosomes, respectively. Mutants carrying a single hemA or hemT disruption grew well without the addition of ALA, whereas a mutant, HemAT1, in which hemA and hemT had both been inactivated required exogenous ALA for growth. The growth rates, ALA synthase enzyme levels, and the amounts of bacteriochlorophyllcontaining intracytoplasmic membrane spectral complexes of all strains were compared. Under photosynthetic growth conditions, the levels of bacteriochlorophyll, carotenoids, and B800-850 and B875 light-harvesting complexes were significantly lower in the Hem mutants than in the wild type. In the mutant strains, available bacteriochlorophyll appeared to be preferentially targeted to the B875 light-harvesting complex relative to the B800-850 complex. In strain HemAT1, the amount of B800-850 complex varied with the concentration of ALA added to the growth medium, and under conditions of ALA limitation, no B800-850 complexes could be detected. In the Hem mutants, there were aberrant transcript levels corresponding to the puc and puf operons encoding structural polypeptides of the B800-850 and B875 complexes. These results suggest that hemA and hemT expression is coupled to the genetic control of the R. sphaeroides photosynthetic apparatus.In the facultative photosynthetic bacterium Rhodobacter sphaeroides, 5-aminolevulinic acid (ALA), the first committed intermediate in tetrapyrrole biosynthesis, is formed from glycine and succinyl coenzyme A (succinyl-CoA) by ALA synthase (succinyl-CoA:glycine C-succinyl transferase [decarboxylating], EC 2.3.1.37). It has previously been shown that ALA formation regulates the production of hemes and bacteriochlorophylls (17). ALA was also shown to affect the transcriptional control of the cytochrome c2 gene, cycA (30). Despite key regulatory roles suggested for this metabolite, however, little is known about the mechanisms by which the formation of ALA is regulated or by which ALA-mediated regulation is exerted.In R. sphaeroides, each of two genes, hemA and hemT, encodes a distinct ALA synthase isozyme (26). Prior to the discovery of isozymes, many studies were interpreted on the assumption of a single ALA synthase. The validity of this assumption seemed to be supported by the isolation of a mutant R. sphaeroides strain, H-5, lacking ALA synthase activity (18). The H-5 and wild-type strains, however, differ...

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Section: Discussionmentioning

confidence: 97%

5-Aminolevulinic acid availability and control of spectral complex formation in hemA and hemT mutants of Rhodobacter sphaeroides

Neidle

Kaplan

1993

J Bacteriol

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“…The second observation was expanded by Neuberger's group in a series of papers (355)(356)(357). That group demonstrated that AlaS from cell extracts could be resolved into two fractions, high-activity and low-activity enzyme fractions.…”

Section: Regulation Of Heme Biosynthesis By Oxygenmentioning

confidence: 99%

Prokaryotic Heme Biosynthesis: Multiple Pathways to a Common Essential Product

Dailey

Gerdes³

et al. 2017

Microbiol Mol Biol Rev

264

335

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SUMMARY The advent of heme during evolution allowed organisms possessing this compound to safely and efficiently carry out a variety of chemical reactions that otherwise were difficult or impossible. While it was long assumed that a single heme biosynthetic pathway existed in nature, over the past decade, it has become clear that there are three distinct pathways among prokaryotes, although all three pathways utilize a common initial core of three enzymes to produce the intermediate uroporphyrinogen III. The most ancient pathway and the only one found in the Archaea converts siroheme to protoheme via an oxygen-independent four-enzyme-step process. Bacteria utilize the initial core pathway but then add one additional common step to produce coproporphyrinogen III. Following this step, Gram-positive organisms oxidize coproporphyrinogen III to coproporphyrin III, insert iron to make coproheme, and finally decarboxylate coproheme to protoheme, whereas Gram-negative bacteria first decarboxylate coproporphyrinogen III to protoporphyrinogen IX and then oxidize this to protoporphyrin IX prior to metal insertion to make protoheme. In order to adapt to oxygen-deficient conditions, two steps in the bacterial pathways have multiple forms to accommodate oxidative reactions in an anaerobic environment. The regulation of these pathways reflects the diversity of bacterial metabolism. This diversity, along with the late recognition that three pathways exist, has significantly slowed advances in this field such that no single organism's heme synthesis pathway regulation is currently completely characterized.

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“…Cells grown on high concentrations of glucose develop very little respiratory activity, and contain smaller amounts of mitochondrial enzymes (Polakis & Bartley, 1965 This enzyme is located within the inner mitochondrial membrane, and since it catalyses the first committed step in haem synthesis, one would expect it to be subject to control. The enzyme and its control has been the subject of many investigations in mammalian, bacterial and yeast systems (Beattie, 1971;Mahler & Lin, 1974;Sandy et al, 1975). Its synthesis is inhibited by haem, an instance of endproduct inhibition (Sinclair & Granick, 1975).…”

Section: Control Ofsterol Biosynthesis In Yeastmentioning

confidence: 99%

The manipulation of cellular cytochrome and lipid composition in a haem mutant of Saccharomyces cerevisiae

Astin¹,

Haslam²

1977

Biochemical Journal

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1. The ole-3 mutant of Saccharomyces cerevisiae has an early lesion in the pathway of porphyrin biosynthesis. 2. This results in the loss ofall haem-containing enzymes, including the mitochondrial cytochromes, and prevents the synthesis of components whose formation requires haem-containing enzymes, including unsaturated fatty acids, ergosterol and methionine. 3. The pleiotropic effects of the primary lesion are reversed by growing mutant ole-3 aerobically in the presence of intermediates of the porphyrin-biosynthetic pathway, and the present work reports the degree ofmanipulation oflipid and respiratorycytochrome composition. 4. Supplements of 5-aminolaevulinate in the range 0.5-500mg/l result in a progressive increase in the cellular content of unsaturated fatty acids and respiratory cytochromes, cause the replacement of lanosterol and squalene by ergosterol, and an increase in total sterol content. 5. Haematoporphyrin and protoporphyrin IX have similar but less extensive effects on cellular composition, whereas haematin allows unsaturated fatty acid synthesis and some sterol synthesis, but has no effect on the formation of respiratory cytochromes. 6. These results suggest that growth of the organism in the presence of defined amounts of 6-aminolaevulinate will be useful in the investigation of the role of lipids and cytochromes in the function and assembly of mitochondrial membranes.

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Control of 5-aminolaevulinate synthetase activity in Rhodopseudomonas spheroides a role for trisulphides

Cited by 57 publications

References 31 publications

5-Aminolevulinic acid availability and control of spectral complex formation in hemA and hemT mutants of Rhodobacter sphaeroides

5-Aminolevulinic acid availability and control of spectral complex formation in hemA and hemT mutants of Rhodobacter sphaeroides

Prokaryotic Heme Biosynthesis: Multiple Pathways to a Common Essential Product

The manipulation of cellular cytochrome and lipid composition in a haem mutant of Saccharomyces cerevisiae

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