Comparative structure, function and regulation of isocitrate lyase, an important assimilatory enzyme

Vanni, P.; Giachetti, E.; Pinzauti, Giancarlo; McFadden, Bruce A.

doi:10.1016/0305-0491(90)90002-b

Cited by 84 publications

(103 citation statements)

References 140 publications

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“…Isocitrate lyase (ICL; EC 4.1.3.1) catalyses the cleavage of isocitrate to glyoxylate and succinate, and plays important roles in the metabolism of acetate and fatty acids in micro-organisms and higher plants as a key enzyme of the glyoxylate cycle (Kornberg, 1966;Vanni et al, 1990;Cozzone, 1998). We previously reported that the ICLs of two psychrophilic bacteria, Colwellia maris and Colwellia psychrerythraea, are homotetrameric, as are their counterparts in other organisms, including Escherichia coli, that they are typical cold-adapted enzymes, and that the expression of the genes encoding these enzymes is cold-inducible (Watanabe et al, 2001(Watanabe et al, , 2002a(Watanabe et al, , 2002b.…”

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confidence: 99%

Amino acid residues involved in cold adaptation of isocitrate lyase from a psychrophilic bacterium, Colwellia maris

Watanabe

2004

Microbiology

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To investigate the mechanism of cold adaptation of isocitrate lyase (ICL; EC 4.1.3.1) from the psychrophilic bacterium Colwellia maris, Gln207 and Gln217 of this enzyme were substituted by His and Lys, respectively, by site-directed mutagenesis. His184 and Lys194 of ICL from Escherichia coli, corresponding to the two Gln residues of C. maris ICL, are highly conserved in the ICLs of many organisms and are known to be essential for catalytic function. The mutated ICLs (Cm-Q207H and Cm-Q217K, respectively) and wild-type enzymes of C. maris and E. coli (Cm-WT and Ec-WT) with His-tagged peptides were overexpressed in E. coli cells and purified to homogeneity. Thermolabile Cm-WT and mutated ICLs were susceptible to digestion with trypsin, while relatively thermostable Ec-WT was resistant to trypsin digestion, suggesting that the thermostability and resistance to tryptic digestion of the ICLs are related. Cm-Q207H and Cm-Q217K showed specific activities similar to Cm-WT at temperatures between 30 6C and 40 6C, but their activities between 10 6C and 25 6C were decreased, indicating that the two Gln residues of the C. maris ICL play important roles in its cold adaptation. Phylogenetic analysis of ICLs from various organisms revealed that the C. maris ICL can be categorized in a novel group, subfamily 3, together with several eubacterial ICLs.

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Section: Introductionmentioning

confidence: 99%

Amino acid residues involved in cold adaptation of isocitrate lyase from a psychrophilic bacterium, Colwellia maris

Watanabe

2004

Microbiology

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“…Given its potential roles in oxidative stress defense, antibiotic resistance, and pathogenesis, the glyoxylate shunt is a promising target for development of new antibiotics. Furthermore, the glyoxylate shunt is widely distributed in bacteria, fungi, some protists, and plants (14) but is absent in most vertebrates.…”

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Role of Glyoxylate Shunt in Oxidative Stress Response

Ahn

Jung

Jang

et al. 2016

Journal of Biological Chemistry

197

161

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The glyoxylate shunt (GS) is a two-step metabolic pathway (isocitrate lyase, aceA; and malate synthase, glcB) that serves as an alternative to the tricarboxylic acid cycle. The GS bypasses the carbon dioxide-producing steps of the tricarboxylic acid cycle and is essential for acetate and fatty acid metabolism in bacteria. GS can be up-regulated under conditions of oxidative stress, antibiotic stress, and host infection, which implies that it plays important but poorly explored roles in stress defense and pathogenesis. In many bacterial species, including Pseudomonas aeruginosa, aceA and glcB are not in an operon, unlike in Escherichia coli. In P. aeruginosa, we explored relationships between GS genes and growth, transcription profiles, and biofilm formation. Contrary to our expectations, deletion of aceA in P. aeruginosa improved cell growth under conditions of oxidative and antibiotic stress. Transcriptome data suggested that aceA mutants underwent a metabolic shift toward aerobic denitrification; this was supported by additional evidence, including up-regulation of denitrification-related genes, decreased oxygen consumption without lowering ATP yield, increased production of denitrification intermediates (NO and N 2 O), and increased cyanide resistance. The aceA mutants also produced a thicker exopolysaccharide layer; that is, a phenotype consistent with aerobic denitrification. A bioinformatic survey across known bacterial genomes showed that only microorganisms capable of aerobic metabolism possess the glyoxylate shunt. This trend is consistent with the hypothesis that the GS plays a previously unrecognized role in allowing bacteria to tolerate oxidative stress.

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“…ICL has been isolated and characterized from a variety of sources, and biochemical studies have shown that the enzymes from different species have similar catalytic properties and kinetic mechanisms (15). In C. reinhardtii, ICL allows growth on acetate as a sole carbon source, and its expression was shown to be regulated by light at the mRNA level (16).…”

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Regulation by Glutathionylation of Isocitrate Lyase from Chlamydomonas reinhardtii

Bedhomme

Zaffagnini

Marchand

et al. 2009

Journal of Biological Chemistry

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Post-translational modification of protein cysteine residues is emerging as an important regulatory and signaling mechanism. We have identified numerous putative targets of redox regulation in the unicellular green alga Chlamydomonas reinhardtii. One enzyme, isocitrate lyase (ICL), was identified both as a putative thioredoxin target and as an S-thiolated protein in vivo. ICL is a key enzyme of the glyoxylate cycle that allows growth on acetate as a sole source of carbon. The aim of the present study was to clarify the molecular mechanism of the redox regulation of Chlamydomonas ICL using a combination of biochemical and biophysical methods. The results clearly show that purified C. reinhardtii ICL can be inactivated by glutathionylation and reactivated by glutaredoxin, whereas thioredoxin does not appear to regulate ICL activity, and no inter-or intramolecular disulfide bond could be formed under any of the conditions tested. Glutathionylation of the protein was investigated by mass spectrometry analysis, Western blotting, and site-directed mutagenesis. The enzyme was found to be protected from irreversible oxidative inactivation by glutathionylation of its catalytic Cys 178 , whereas a second residue, Cys 247 , becomes artifactually glutathionylated after prolonged incubation with GSSG. The possible functional significance of this post-translational modification of ICL in Chlamydomonas and other organisms is discussed.

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Comparative structure, function and regulation of isocitrate lyase, an important assimilatory enzyme

Cited by 84 publications

References 140 publications

Amino acid residues involved in cold adaptation of isocitrate lyase from a psychrophilic bacterium, Colwellia maris

Amino acid residues involved in cold adaptation of isocitrate lyase from a psychrophilic bacterium, Colwellia maris

Role of Glyoxylate Shunt in Oxidative Stress Response

Regulation by Glutathionylation of Isocitrate Lyase from Chlamydomonas reinhardtii

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