Biosynthesis of arsenolipids by the cyanobacterium Synechocystis sp. PCC 6803

Xi-Mei Xue, Georg Raber, Simon FOSTER, Song-Can Chen, Kevin Francesconi, Yong-Guan Zhu

    Research output: Contribution to journalArticle

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    Abstract

    Environmental context Arsenic biotransformation processes play a key role in the cycling of arsenic in aquatic systems. We show that a freshwater cyanobacterium can convert inorganic arsenic into arsenolipids, and the conversion efficiency depends on the arsenic concentration. The role of these novel arsenic compounds remains to be elucidated. Abstract Although methylated arsenic and arsenosugars have been verified in various freshwater organisms, lipid-soluble arsenic compounds have not been identified. Here, we report investigations with the model organism cyanobacterium Synechocystis sp. PCC 6803 wild type and ΔarsM (arsenic(III) S-adenosylmethionine methyltransferase) mutant strain, which lacks the enzymes for arsenic methylation cultured in various concentrations of arsenate (AsV). Although Synechocystis accumulated higher arsenic concentrations at the higher exposure levels, the bioaccumulation factor decreased with increasing AsV. The accumulated arsenic in the cells was partitioned into water-soluble and lipid-soluble fractions; lipid-soluble arsenic was found in Synechocystis wild type cells (3-35% of the total depending on the level of arsenic exposure), but was not detected in Synechocystis ΔarsM mutant strain showing that ArsM was required for arsenolipid biosynthesis. The arsenolipids present in Synechocystis sp. PCC 6803 were analysed by high performance liquid chromatography-inductively coupled plasma-mass spectrometry, high performance liquid chromatography-electrospray mass spectrometry, and high resolution tandem mass spectrometry. The two major arsenolipids were characterised as arsenosugar phospholipids based on their assigned molecular formulas C47H88O14AsP and C47H90O14AsP, and tandem mass spectrometric data demonstrated the presence of the phosphate arsenosugar and acylated glycerol groups.

    Original languageEnglish
    Pages (from-to)506-513
    Number of pages8
    JournalEnvironmental Chemistry
    Volume11
    Issue number5
    DOIs
    Publication statusPublished - 2014

    Fingerprint

    Biosynthesis
    Arsenic
    cyanobacterium
    arsenic
    Arsenicals
    High performance liquid chromatography
    Lipids
    mass spectrometry
    lipid
    Mass spectrometry
    Cyanobacteria
    biosynthesis
    liquid chromatography
    Inductively coupled plasma mass spectrometry
    S-Adenosylmethionine
    Bioaccumulation
    Methylation
    Methyltransferases
    Glycerol
    methylation

    Cite this

    Xue, Xi-Mei ; Raber, Georg ; FOSTER, Simon ; Chen, Song-Can ; Francesconi, Kevin ; Zhu, Yong-Guan. / Biosynthesis of arsenolipids by the cyanobacterium Synechocystis sp. PCC 6803. In: Environmental Chemistry. 2014 ; Vol. 11, No. 5. pp. 506-513.
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    abstract = "Environmental context Arsenic biotransformation processes play a key role in the cycling of arsenic in aquatic systems. We show that a freshwater cyanobacterium can convert inorganic arsenic into arsenolipids, and the conversion efficiency depends on the arsenic concentration. The role of these novel arsenic compounds remains to be elucidated. Abstract Although methylated arsenic and arsenosugars have been verified in various freshwater organisms, lipid-soluble arsenic compounds have not been identified. Here, we report investigations with the model organism cyanobacterium Synechocystis sp. PCC 6803 wild type and ΔarsM (arsenic(III) S-adenosylmethionine methyltransferase) mutant strain, which lacks the enzymes for arsenic methylation cultured in various concentrations of arsenate (AsV). Although Synechocystis accumulated higher arsenic concentrations at the higher exposure levels, the bioaccumulation factor decreased with increasing AsV. The accumulated arsenic in the cells was partitioned into water-soluble and lipid-soluble fractions; lipid-soluble arsenic was found in Synechocystis wild type cells (3-35{\%} of the total depending on the level of arsenic exposure), but was not detected in Synechocystis ΔarsM mutant strain showing that ArsM was required for arsenolipid biosynthesis. The arsenolipids present in Synechocystis sp. PCC 6803 were analysed by high performance liquid chromatography-inductively coupled plasma-mass spectrometry, high performance liquid chromatography-electrospray mass spectrometry, and high resolution tandem mass spectrometry. The two major arsenolipids were characterised as arsenosugar phospholipids based on their assigned molecular formulas C47H88O14AsP and C47H90O14AsP, and tandem mass spectrometric data demonstrated the presence of the phosphate arsenosugar and acylated glycerol groups.",
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    Xue, X-M, Raber, G, FOSTER, S, Chen, S-C, Francesconi, K & Zhu, Y-G 2014, 'Biosynthesis of arsenolipids by the cyanobacterium Synechocystis sp. PCC 6803', Environmental Chemistry, vol. 11, no. 5, pp. 506-513. https://doi.org/10.1071/EN14069

    Biosynthesis of arsenolipids by the cyanobacterium Synechocystis sp. PCC 6803. / Xue, Xi-Mei; Raber, Georg; FOSTER, Simon; Chen, Song-Can; Francesconi, Kevin; Zhu, Yong-Guan.

    In: Environmental Chemistry, Vol. 11, No. 5, 2014, p. 506-513.

    Research output: Contribution to journalArticle

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    AU - Xue, Xi-Mei

    AU - Raber, Georg

    AU - FOSTER, Simon

    AU - Chen, Song-Can

    AU - Francesconi, Kevin

    AU - Zhu, Yong-Guan

    PY - 2014

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    N2 - Environmental context Arsenic biotransformation processes play a key role in the cycling of arsenic in aquatic systems. We show that a freshwater cyanobacterium can convert inorganic arsenic into arsenolipids, and the conversion efficiency depends on the arsenic concentration. The role of these novel arsenic compounds remains to be elucidated. Abstract Although methylated arsenic and arsenosugars have been verified in various freshwater organisms, lipid-soluble arsenic compounds have not been identified. Here, we report investigations with the model organism cyanobacterium Synechocystis sp. PCC 6803 wild type and ΔarsM (arsenic(III) S-adenosylmethionine methyltransferase) mutant strain, which lacks the enzymes for arsenic methylation cultured in various concentrations of arsenate (AsV). Although Synechocystis accumulated higher arsenic concentrations at the higher exposure levels, the bioaccumulation factor decreased with increasing AsV. The accumulated arsenic in the cells was partitioned into water-soluble and lipid-soluble fractions; lipid-soluble arsenic was found in Synechocystis wild type cells (3-35% of the total depending on the level of arsenic exposure), but was not detected in Synechocystis ΔarsM mutant strain showing that ArsM was required for arsenolipid biosynthesis. The arsenolipids present in Synechocystis sp. PCC 6803 were analysed by high performance liquid chromatography-inductively coupled plasma-mass spectrometry, high performance liquid chromatography-electrospray mass spectrometry, and high resolution tandem mass spectrometry. The two major arsenolipids were characterised as arsenosugar phospholipids based on their assigned molecular formulas C47H88O14AsP and C47H90O14AsP, and tandem mass spectrometric data demonstrated the presence of the phosphate arsenosugar and acylated glycerol groups.

    AB - Environmental context Arsenic biotransformation processes play a key role in the cycling of arsenic in aquatic systems. We show that a freshwater cyanobacterium can convert inorganic arsenic into arsenolipids, and the conversion efficiency depends on the arsenic concentration. The role of these novel arsenic compounds remains to be elucidated. Abstract Although methylated arsenic and arsenosugars have been verified in various freshwater organisms, lipid-soluble arsenic compounds have not been identified. Here, we report investigations with the model organism cyanobacterium Synechocystis sp. PCC 6803 wild type and ΔarsM (arsenic(III) S-adenosylmethionine methyltransferase) mutant strain, which lacks the enzymes for arsenic methylation cultured in various concentrations of arsenate (AsV). Although Synechocystis accumulated higher arsenic concentrations at the higher exposure levels, the bioaccumulation factor decreased with increasing AsV. The accumulated arsenic in the cells was partitioned into water-soluble and lipid-soluble fractions; lipid-soluble arsenic was found in Synechocystis wild type cells (3-35% of the total depending on the level of arsenic exposure), but was not detected in Synechocystis ΔarsM mutant strain showing that ArsM was required for arsenolipid biosynthesis. The arsenolipids present in Synechocystis sp. PCC 6803 were analysed by high performance liquid chromatography-inductively coupled plasma-mass spectrometry, high performance liquid chromatography-electrospray mass spectrometry, and high resolution tandem mass spectrometry. The two major arsenolipids were characterised as arsenosugar phospholipids based on their assigned molecular formulas C47H88O14AsP and C47H90O14AsP, and tandem mass spectrometric data demonstrated the presence of the phosphate arsenosugar and acylated glycerol groups.

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    UR - http://www.mendeley.com/research/biosynthesis-arsenolipids-cyanobacterium-synechocystis-sp-pcc-6803

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