ToxT: Difference between revisions
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==Structural Features== | ==Structural Features== | ||
ToxT belongs to a family of transcriptional regulators known as AraC.<ref name="structure">PMID: 20133655</ref> The AraC family is defined by a 100 amino acid region of sequence similarity that forms a DNA-binding domain with two helix-turn-helix motifs. <ref name="arac">PMID: 11282467</ref> The two HTH regions are linked by another alpha helix, which is very polar. | ToxT belongs to a family of transcriptional regulators known as AraC.<ref name="structure">PMID: 20133655</ref> The AraC family is defined by a 100 amino acid region of sequence similarity that forms a DNA-binding domain with two helix-turn-helix motifs. <ref name="arac">PMID: 11282467</ref> The two HTH regions are linked by another alpha helix, which is very polar. | ||
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A nine-stranded beta sheet sandwich<!--insert scene here!--> contains a binding pocket that contains a ligand: cis-palmitoleate,<!--insert scene here!--> <ref name="structure">PMID: 20133655</ref> which appears to have a negative effect on virulence when present in vitro. This unsaturated fatty acid, like other UFAs,[http://http://en.wikipedia.org/wiki/Fatty_acid#Unsaturated_fatty_acids] tend to inhibit genes under the control of ToxT. | A nine-stranded beta sheet sandwich<!--insert scene here!--> contains a binding pocket that contains a ligand: cis-palmitoleate,<!--insert scene here!--> <ref name="structure">PMID: 20133655</ref> which appears to have a negative effect on virulence when present in vitro. This unsaturated fatty acid, like other UFAs,[http://http://en.wikipedia.org/wiki/Fatty_acid#Unsaturated_fatty_acids] tend to inhibit genes under the control of ToxT. | ||
Specifically, the cis-palmitoleate appears to bind directly to ToxT, change its conformation, and thus lower the ability to bind DNA and form dimers.<ref name="structure">PMID: 20133655</ref> | Specifically, the cis-palmitoleate appears to bind directly to ToxT, change its conformation, and thus lower the ability to bind DNA and form dimers.<ref name="structure">PMID: 20133655</ref> | ||
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Though the structure shown is a monomer with two overall domains (N-terminal and C-terminal), ToxT tends to form a dimer. The preferred state of ToxT varies between promoters, but binding to the <i>ctx</i> promoter to generate cholera toxin appears to be possible only in the dimer form. <ref name="virstatin">PMID:17283330</ref> | Though the structure shown is a monomer with two overall domains (N-terminal and C-terminal), ToxT tends to form a dimer. The preferred state of ToxT varies between promoters, but binding to the <i>ctx</i> promoter to generate cholera toxin appears to be possible only in the dimer form. <ref name="virstatin">PMID:17283330</ref> | ||
==References== | ==References== | ||
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