Sandbox Reserved 1069: Difference between revisions

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The conformation change directly involved with Zn2+/H+ antiport occurs in the TMD as helix pivoting controls what environment site A is available to. Conformation change occurs when the transmembrane helix pairs TM1, TM2, TM4, and TM5 pivot around cation binding site A.<ref>PMID:23341604</ref>

It is believed that the energy for TMD conformation change comes from energy of binding each substrate. Changing to the outward from the inward-facing conformation causes a shift in <scene name='69/~~694233~~/~~Transmembrane_helix_5~~/2'>TM5</scene> which disrupts the tetrahedral geometry of active site A. This in turn decreases binding affinity site A has for Zn2+ making export to the periplasm possible. After Zn2+ is exported and site A is either empty or bound to H+, the protein's conformation changes to the favored inward-facing conformation.

It is believed that the energy for TMD conformation change comes from energy of binding each substrate. Changing to the outward from the inward-facing conformation causes a shift in the <scene name='69/694236/Shorttm5/1'>TM5 helix</scene> which disrupts the tetrahedral geometry of active site A. This in turn decreases binding affinity site A has for Zn2+ making export to the periplasm possible. After Zn2+ is exported and site A is either empty or bound to H+, the protein's conformation changes to the favored inward-facing conformation.

[[Image:FRET.png|200px|left|thumb| Figure 7. Labeled Cysteine resides measured with FRET showed the distance of the CTD of each monomer to be 24.0Å when saturated with Zn2+. Decrease in the Cys-Cys distance is indicative that both CTDs of YiiP were brought closer together.]]

In contrast the main purpose of conformation change in the CTD is to stabilize the YiiP dimer and to act as a Zn2+ sensor.

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 The conformation change directly involved with Zn<sup>2+</sup>/H<sup>+</sup> antiport occurs in the TMD as helix pivoting controls what environment site A is available to. Conformation change occurs when the transmembrane helix pairs TM1, TM2, TM4, and TM5 pivot around cation binding site A.<ref>PMID:23341604</ref>
-It is believed that the energy for TMD conformation change comes from energy of binding each substrate. Changing to the outward from the inward-facing conformation causes a shift in <scene name='69/694233/Transmembrane_helix_5/2'>TM5</scene> which disrupts the tetrahedral geometry of active site A. This in turn decreases binding affinity site A has for Zn<sup>2+</sup> making export to the periplasm possible. After Zn<sup>2+</sup> is exported and site A is either empty or bound to H<sup>+</sup>, the protein's conformation changes to the favored inward-facing conformation.
+It is believed that the energy for TMD conformation change comes from energy of binding each substrate. Changing to the outward from the inward-facing conformation causes a shift in the <scene name='69/694236/Shorttm5/1'>TM5 helix</scene> which disrupts the tetrahedral geometry of active site A. This in turn decreases binding affinity site A has for Zn<sup>2+</sup> making export to the periplasm possible. After Zn<sup>2+</sup> is exported and site A is either empty or bound to H<sup>+</sup>, the protein's conformation changes to the favored inward-facing conformation.
 [[Image:FRET.png|200px|left|thumb| Figure 7. Labeled Cysteine resides measured with FRET showed the distance of the CTD of each monomer to be 24.0Å when saturated with Zn<sup>2+</sup>. Decrease in the Cys-Cys distance is indicative that both CTDs of YiiP were brought closer together.]]
 In contrast the main purpose of conformation change in the CTD is to stabilize the YiiP dimer and to act as a Zn<sup>2+</sup> sensor.

Sandbox Reserved 1069: Difference between revisions

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