Sandbox Reserved 1600: Difference between revisions

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=Introduction=

<scene name='83/838655/Bdoxidase_structure_full/4'>Cytochrome bd oxidase</scene> is an integral membrane protein that catalyzes the reduction of oxygen to water using quinol as the reducing substrate.<ref name=”Giuffrè”>PMID:24486503</ref>. The full reaction is O₂ + 4H+ + 4e- → 2H₂O. The reaction is electrogenic but it is not coupled to a proton pump. Instead, bd oxidase utilizes internal water molecules to provide the four protons needed and an external ubiquinol molecule for the four electrons needed <ref name = ”Safarian”>PMID:31604309</ref>~~. To catalyze the reaction, oxygen enters through a selective entry site within the enzyme~~.

<scene name='83/838655/Bdoxidase_structure_full/4'>Cytochrome bd oxidase</scene> is an integral membrane protein that catalyzes the reduction of oxygen to water using quinol as the reducing substrate.<ref name=”Giuffrè”>PMID:24486503</ref>. The full reaction is O₂ + 4H+ + 4e- → 2H₂O. The reaction is electrogenic but it is not coupled to a proton pump. Instead, bd oxidase utilizes internal water molecules to provide the four protons needed and an external ubiquinol molecule for the four electrons needed <ref name = ”Safarian”>PMID:31604309</ref>.

There are two main types of respiratory cytochrome oxidases: the heme/copper oxidases, and the heme-only cytochrome bd quinol oxidase, which is what bd oxidase falls under. <ref name=”Das”>PMID:15743950</ref> Heme-only cytochrome bd quinol oxidases are associated with microaerobic dioxygen respiration, and they have a high affinity for oxygen.

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Cytochrome bd oxidase plays a key role in protecting gram-negative heterotrophs from high oxidative stress (ie. preventing free radicals in intracellular space in prokaryotes). <ref name=”Jünemann”>PMID:9332500</ref>. Other organisms, like humans, have mechanisms that do the same thing but are more intricate due to the organism’s higher levels of complexity.

The ''Geobacillus thermodenitrificans'' organism utilizes the bd oxidase mechanism. The oxygen enters the enzyme through the selective <scene name='83/832926/Potential_oxygen_entry_site/1'>oxygen entry site</scene> that funnels the extracellular oxygen to <scene name='83/838655/Bd_oxidase_heme_d/1'>Heme D</scene> in the active site. The electrons for the reaction are provided by ubiquinol ~~molecules~~. The protons for the reaction are provided by one of two <scene name='83/838655/Bdoxidase_proton_pathways/1'>potential proton pathways</scene>, either the <scene name='83/838655/Bdoxidase_cyda_pathway/6'>CydA pathway</scene>or <scene name='83/838655/Bdoxidase_cydb_pathway/3'>CydB pathway</scene>. Both of the proton pathways utilize the intracellular water molecules for the proton source, and shuttle them to <scene name='83/838655/Bd_oxidase_heme_b_595/1'>Heme B595</scene>.

The ''Geobacillus thermodenitrificans'' organism utilizes the bd oxidase mechanism. The oxygen enters the enzyme through the selective <scene name='83/832926/Potential_oxygen_entry_site/1'>oxygen entry site</scene> that funnels the extracellular oxygen to <scene name='83/838655/Bd_oxidase_heme_d/1'>Heme D</scene> in the active site. The electrons for the reaction are provided by ubiquinol molecule bound to the <scene name='83/838655/Bdoxidase_q_loop/2'>Q loop</scene>. The protons for the reaction are provided by one of two <scene name='83/838655/Bdoxidase_proton_pathways/1'>potential proton pathways</scene>, either the <scene name='83/838655/Bdoxidase_cyda_pathway/6'>CydA pathway</scene>or <scene name='83/838655/Bdoxidase_cydb_pathway/3'>CydB pathway</scene>. Both of the proton pathways utilize the intracellular water molecules for the proton source, and shuttle them to <scene name='83/838655/Bd_oxidase_heme_b_595/1'>Heme B595</scene>.

= Biological Importance of Reducing O₂ =

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@@ Line 6: / Line 6: @@
 =Introduction=
-<scene name='83/838655/Bdoxidase_structure_full/4'>Cytochrome bd oxidase</scene> is an integral membrane protein that catalyzes the reduction of oxygen to water using quinol as the reducing substrate.<ref name=”Giuffrè”>PMID:24486503</ref>. The full reaction is O₂ + 4H<sup>+</sup> + 4e<sup>-</sup> → 2H₂O. The reaction is electrogenic but it is not coupled to a proton pump. Instead, bd oxidase utilizes internal water molecules to provide the four protons needed and an external ubiquinol molecule for the four electrons needed <ref name = ”Safarian”>PMID:31604309</ref>. To catalyze the reaction, oxygen enters through a selective entry site within the enzyme.
+<scene name='83/838655/Bdoxidase_structure_full/4'>Cytochrome bd oxidase</scene> is an integral membrane protein that catalyzes the reduction of oxygen to water using quinol as the reducing substrate.<ref name=”Giuffrè”>PMID:24486503</ref>. The full reaction is O₂ + 4H<sup>+</sup> + 4e<sup>-</sup> → 2H₂O. The reaction is electrogenic but it is not coupled to a proton pump. Instead, bd oxidase utilizes internal water molecules to provide the four protons needed and an external ubiquinol molecule for the four electrons needed <ref name = ”Safarian”>PMID:31604309</ref>.
 There are two main types of respiratory cytochrome oxidases: the heme/copper oxidases, and the heme-only cytochrome bd quinol oxidase, which is what bd oxidase falls under. <ref name=”Das”>PMID:15743950</ref> Heme-only cytochrome bd quinol oxidases are associated with microaerobic dioxygen respiration, and they have a high affinity for oxygen.
@@ Line 12: / Line 12: @@
 Cytochrome bd oxidase plays a key role in protecting gram-negative heterotrophs from high oxidative stress (ie. preventing free radicals in intracellular space in prokaryotes). <ref name=”Jünemann”>PMID:9332500</ref>. Other organisms, like humans, have mechanisms that do the same thing but are more intricate due to the organism’s higher levels of complexity.
-The ''Geobacillus thermodenitrificans'' organism utilizes the bd oxidase mechanism. The oxygen enters the enzyme through the selective <scene name='83/832926/Potential_oxygen_entry_site/1'>oxygen entry site</scene> that funnels the extracellular oxygen to <scene name='83/838655/Bd_oxidase_heme_d/1'>Heme D</scene> in the active site. The electrons for the reaction are provided by ubiquinol molecules. The protons for the reaction are provided by one of two <scene name='83/838655/Bdoxidase_proton_pathways/1'>potential proton pathways</scene>, either the <scene name='83/838655/Bdoxidase_cyda_pathway/6'>CydA pathway</scene>or <scene name='83/838655/Bdoxidase_cydb_pathway/3'>CydB pathway</scene>. Both of the proton pathways utilize the intracellular water molecules for the proton source, and shuttle them to <scene name='83/838655/Bd_oxidase_heme_b_595/1'>Heme B595</scene>.
+The ''Geobacillus thermodenitrificans'' organism utilizes the bd oxidase mechanism. The oxygen enters the enzyme through the selective <scene name='83/832926/Potential_oxygen_entry_site/1'>oxygen entry site</scene> that funnels the extracellular oxygen to <scene name='83/838655/Bd_oxidase_heme_d/1'>Heme D</scene> in the active site. The electrons for the reaction are provided by ubiquinol molecule bound to the <scene name='83/838655/Bdoxidase_q_loop/2'>Q loop</scene>. The protons for the reaction are provided by one of two <scene name='83/838655/Bdoxidase_proton_pathways/1'>potential proton pathways</scene>, either the <scene name='83/838655/Bdoxidase_cyda_pathway/6'>CydA pathway</scene>or <scene name='83/838655/Bdoxidase_cydb_pathway/3'>CydB pathway</scene>. Both of the proton pathways utilize the intracellular water molecules for the proton source, and shuttle them to <scene name='83/838655/Bd_oxidase_heme_b_595/1'>Heme B595</scene>.
 = Biological Importance of Reducing O₂ =