Sandbox Reserved 1600: Difference between revisions
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<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>. | <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 | 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. | ||
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) | 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 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>. | 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>. | ||