Chloroplast pentose‐5‐phosphate 3‐epimerase from potato: cloning, cDNA sequence, and tissue‐specific enzyme accumulation

Teige, Markus; Bauwe, Hermann; Süss, Karl-Heinz

doi:10.1016/0014-5793(95)01373-3

Cited by 20 publications

(2 citation statements)

References 13 publications

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“…This seems to be the case for the plastidiar PGL, thus explaining why its detection by MS had been so difficult. In contrast other metabolic enzymes like transketolase accumulate at much higher levels as related metabolic enzymes 61 or as it would be expected based on their transcript levels 60, even enabling its protein purification from plant tissues 62.…”

Section: Resultsmentioning

confidence: 99%

Mining the soluble chloroplast proteome by affinity chromatography

Bayer¹,

Stael²,

Csaszar³

et al. 2011

Proteomics

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Chloroplasts are fundamental organelles enabling plant photoautotrophy. Besides their outstanding physiological role in fixation of atmospheric CO2, they harbor many important metabolic processes such as biosynthesis of amino acids, vitamins or hormones. Technical advances in MS allowed the recent identification of most chloroplast proteins. However, for a deeper understanding of chloroplast function it is important to obtain a complete list of constituents, which is so far limited by the detection of low-abundant proteins. Therefore, we developed a two-step strategy for the enrichment of low-abundant soluble chloroplast proteins from Pisum sativum and their subsequent identification by MS. First, chloroplast protein extracts were depleted from the most abundant protein ribulose-1,5-bisphosphate carboxylase/oxygenase by SEC or heating. Further purification was carried out by affinity chromatography, using ligands specific for ATP- or metal-binding proteins. By these means, we were able to identify a total of 448 proteins including 43 putative novel chloroplast proteins. Additionally, the chloroplast localization of 13 selected proteins was confirmed using yellow fluorescent protein fusion analyses. The selected proteins included a phosphoglycerate mutase, a cysteine protease, a putative protein kinase and an EF-hand containing substrate carrier protein, which are expected to exhibit important metabolic or regulatory functions.

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Section: Resultsmentioning

confidence: 99%

Mining the soluble chloroplast proteome by affinity chromatography

Bayer¹,

Stael²,

Csaszar³

et al. 2011

Proteomics

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“…Proteins belonging to the LTs (Lytic Murein Transglycosylases) family cleave the polysaccharide of the peptidoglycan at the NAM-NAG glycosidic bond by intramolecular cyclization of the n -acetylmuramyl moiety to yield a 1,6-anhydro- n -acetyl-β- d -muramyl (1,6-anhydroMurNAc) product during the peptidoglycan biosynthesis [ 16 ]. On the other hand, epimerases are usually involved in metabolic pathways such as inversion of D-alanine and D-glutamate for bacterial cell wall metabolism [ 25 ]; biosynthesis of a variety of cell surface polysaccharides; biosynthesis of LPS and capsular sugar precursors [ 43 ]; and complex biosynthetic pathways, such as Glycolysis, Entner-Doudoroff, Leloir and others that present several chemical steps [ 44 , 45 ]. Epimerases are also involved in oxidation, acetylation, dehydration, and carbohydrate reduction (reviewed by [ 40 ]).…”

Section: Discussionmentioning

confidence: 99%

XAC4296 Is a Multifunctional and Exclusive Xanthomonadaceae Gene Containing a Fusion of Lytic Transglycosylase and Epimerase Domains

et al. 2022

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Microorganisms have a limited and highly adaptable repertoire of genes capable of encoding proteins containing single or variable multidomains. The phytopathogenic bacteria Xanthomonas citri subsp. citri (X. citri) (Xanthomonadaceae family), the etiological agent of Citrus Canker (CC), presents a collection of multidomain and multifunctional enzymes (MFEs) that remains to be explored. Recent studies have shown that multidomain enzymes that act on the metabolism of the peptidoglycan and bacterial cell wall, belonging to the Lytic Transglycosylases (LTs) superfamily, play an essential role in X. citri biology. One of these LTs, named XAC4296, apart from the Transglycosylase SLT_2 and Peptidoglycan binding-like domains, contains an unexpected aldose 1-epimerase domain linked to the central metabolism; therefore, resembling a canonical MFE. In this work, we experimentally characterized XAC4296 revealing its role as an MFE and demonstrating its probable gene fusion origin and evolutionary history. The XAC4296 is expressed during plant-pathogen interaction, and the Δ4296 mutant impacts CC progression. Moreover, Δ4296 exhibited chromosome segregation and cell division errors, and sensitivity to ampicillin, suggesting not only LT activity but also that the XAC4296 may also contribute to resistance to β-lactams. However, both Δ4296 phenotypes can be restored when the mutant is supplemented with sucrose or glutamic acid as a carbon and nitrogen source, respectively; therefore, supporting the epimerase domain’s functional relationship with the central carbon and cell wall metabolism. Taken together, these results elucidate the role of XAC4296 as an MFE in X. citri, also bringing new insights into the evolution of multidomain proteins and antimicrobial resistance in the Xanthomonadaceae family.

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