Difference between revisions of "Part:BBa K1420000"

(→‎Components of the mer operon)
(→‎Components of the mer operon)
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converts organomercuric and cationic mercury to the less toxic volatile mercury.
 
converts organomercuric and cationic mercury to the less toxic volatile mercury.
  
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== Components of the ''mer'' operon ==
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== Function and Components of the ''mer'' operon ==
  
 
<p>''merR''</p>
 
<p>''merR''</p>
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<p>''merR'', located upstream of the rest of the mer operon mercury resistance genes, serves to regulate the mer operon by activating transcription in the presence of Hg(II) and acting as a weak repressor in the absence of Hg(II).  The effector binding region of MerR family proteins can vary allowing for great diversity in MerR-like promoters that can respond to a variety of heavy metals as well as antibiotics and oxidative stress. This variable nature of MerR family proteins makes them a valuable tool for various heavy metal detection and bioremediation. (For more information on the ''merR'' gene, see part BBa_K1420004.)</p>
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<p>''merR'', located upstream of the rest of the mer operon mercury resistance genes, serves to regulate the mer operon by activating transcription in the presence of Hg(II) and acting as a weak repressor in the absence of Hg(II).  The effector binding region of MerR family proteins can vary allowing for great diversity in MerR-like promoters that can respond to a variety of heavy metals as well as antibiotics and oxidative stress. This variable nature of MerR family proteins makes them a valuable tool for various heavy metal detection and bioremediation. (For more information on the each individual gene of the ''mer'' operon, see the following parts pages: BBa_K1420001 for ''merA'', BBa_K1420002 for ''merB'', BBa_K1420003 for ''merP'', BBa_K1420004 for ''merR'', and BBa_K1420005 for ''merT''.)</p>
  
 
<p>''merT''</p>
 
<p>''merT''</p>
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<p>Transmembrane mercuric binding gene ''merT'' encodes MerT, which transports Hg(II) species from the periplasm through the membrane. Hg(II) is transferred from the periplasmic cysteine pair on the first transmembrane helix to the cytoplasmic loop cysteine, where it is finally transferred to a cysteine pair at the N-terminus of the protein. The Hg(II) may go directly to MerA from the N-terminus of MerT or transfer to cytoplasmic low-molecular mass thiols.(For more information on the ''merT'' gene, see part BBa_K1420005.)</p>
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<p>Transmembrane mercuric binding gene ''merT'' encodes MerT, which transports Hg(II) species from the periplasm through the membrane. Hg(II) is transferred from the periplasmic cysteine pair on the first transmembrane helix to the cytoplasmic loop cysteine, where it is finally transferred to a cysteine pair at the N-terminus of the protein. The Hg(II) may go directly to MerA from the N-terminus of MerT or transfer to cytoplasmic low-molecular mass thiols.</p>
  
 
<p>''merP''</p>
 
<p>''merP''</p>
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<p>''merP'' encodes the periplasmic transport protein, MerP. This enzyme binds a single Hg(II) ion at two conserved cysteine residues which define its metal binding motif. The MerP cysteine residues take up a Hg(II) ion and remove any attached ligands before passing the ion to the MerT transmembrane protein. (For more information on the ''merP'' gene, see part BBa_K1420003.)</p>
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<p>''merP'' encodes the periplasmic transport protein, MerP. This enzyme binds a single Hg(II) ion at two conserved cysteine residues which define its metal binding motif. The MerP cysteine residues take up a Hg(II) ion and remove any attached ligands before passing the ion to the MerT transmembrane protein.</p>
  
 
<p>''merA''</p>
 
<p>''merA''</p>
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<p>Mercury resistance gene merA encodes MerA, a mercuric ion reductase (cytosolic, flavin disulfide oxidoreductase), that is essential to bacterial mercury resistance. MerA catalyzes the reduction of mercuric ion released from protonlysis of organomercury (catalyzed by MerB) to the relative inert, volatile monoatomic mercury in a NADPH dependent reaction. (For more information on the ''merA'' gene, see part BBa_K1420001.)</p>
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<p>Mercury resistance gene merA encodes MerA, a mercuric ion reductase (cytosolic, flavin disulfide oxidoreductase), that is essential to bacterial mercury resistance. MerA catalyzes the reduction of mercuric ion released from protonlysis of organomercury (catalyzed by MerB) to the relative inert, volatile monoatomic mercury in a NADPH dependent reaction. </p>
  
 
<p>''merB''</p>
 
<p>''merB''</p>
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<p>The ''merB'' gene is often found immediately downstream of ''merA'', and is essential for the detoxification and bioremediation of organic toxic mercury compounds in congruence with ''merA''. The ''merB'' protein is a lyase that catalyzes the breaking of carbon-mercury bonds through protonolysis of toxic mercury compounds, such as methylmercury. This produces the less toxic and less mobile Hg<sup>2+</sup> which is then completely volatilized to Hg<sup>0</sup> when acted upon the enzyme ''merA''. (For more information on the ''merB'' gene, see part BBa_K1420002.)</p>
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<p>The ''merB'' gene is often found immediately downstream of ''merA'', and is essential for the detoxification and bioremediation of organic toxic mercury compounds in congruence with ''merA''. The ''merB'' protein is a lyase that catalyzes the breaking of carbon-mercury bonds through protonolysis of toxic mercury compounds, such as methylmercury. This produces the less toxic and less mobile Hg<sup>2+</sup> which is then completely volatilized to Hg<sup>0</sup> when acted upon the enzyme ''merA''.</p>
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== Construction of the pBBRBB::''mer'' plasmid ==
 
== Construction of the pBBRBB::''mer'' plasmid ==

Revision as of 17:47, 17 October 2014

Mer operon, biological system found to detoxify organic and inorganic forms of mercury

converts organomercuric and cationic mercury to the less toxic volatile mercury.

Function and Components of the mer operon

merR

merR, located upstream of the rest of the mer operon mercury resistance genes, serves to regulate the mer operon by activating transcription in the presence of Hg(II) and acting as a weak repressor in the absence of Hg(II). The effector binding region of MerR family proteins can vary allowing for great diversity in MerR-like promoters that can respond to a variety of heavy metals as well as antibiotics and oxidative stress. This variable nature of MerR family proteins makes them a valuable tool for various heavy metal detection and bioremediation. (For more information on the each individual gene of the mer operon, see the following parts pages: BBa_K1420001 for merA, BBa_K1420002 for merB, BBa_K1420003 for merP, BBa_K1420004 for merR, and BBa_K1420005 for merT.)

merT

Transmembrane mercuric binding gene merT encodes MerT, which transports Hg(II) species from the periplasm through the membrane. Hg(II) is transferred from the periplasmic cysteine pair on the first transmembrane helix to the cytoplasmic loop cysteine, where it is finally transferred to a cysteine pair at the N-terminus of the protein. The Hg(II) may go directly to MerA from the N-terminus of MerT or transfer to cytoplasmic low-molecular mass thiols.

merP

merP encodes the periplasmic transport protein, MerP. This enzyme binds a single Hg(II) ion at two conserved cysteine residues which define its metal binding motif. The MerP cysteine residues take up a Hg(II) ion and remove any attached ligands before passing the ion to the MerT transmembrane protein.

merA

Mercury resistance gene merA encodes MerA, a mercuric ion reductase (cytosolic, flavin disulfide oxidoreductase), that is essential to bacterial mercury resistance. MerA catalyzes the reduction of mercuric ion released from protonlysis of organomercury (catalyzed by MerB) to the relative inert, volatile monoatomic mercury in a NADPH dependent reaction.

merB

The merB gene is often found immediately downstream of merA, and is essential for the detoxification and bioremediation of organic toxic mercury compounds in congruence with merA. The merB protein is a lyase that catalyzes the breaking of carbon-mercury bonds through protonolysis of toxic mercury compounds, such as methylmercury. This produces the less toxic and less mobile Hg2+ which is then completely volatilized to Hg0 when acted upon the enzyme merA.

Construction of the pBBRBB::mer plasmid

Sequence and Features


Assembly Compatibility:
  • 10
    COMPATIBLE WITH RFC[10]
  • 12
    INCOMPATIBLE WITH RFC[12]
    Illegal NheI site found at 551
  • 21
    COMPATIBLE WITH RFC[21]
  • 23
    COMPATIBLE WITH RFC[23]
  • 25
    INCOMPATIBLE WITH RFC[25]
    Illegal NgoMIV site found at 2420
    Illegal NgoMIV site found at 2468
    Illegal NgoMIV site found at 2530
    Illegal NgoMIV site found at 2741
    Illegal NgoMIV site found at 3334
  • 1000
    INCOMPATIBLE WITH RFC[1000]
    Illegal SapI site found at 536