Sandbox Reserved 1600: Difference between revisions
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Because there is no proton pump present, the proton transfer mechanism is facilitated by <scene name='83/838655/Bdoxidase_proton_pathways/1'>2 potential proton pathways</scene> via intracellular water molecules. | Because there is no proton pump present, the proton transfer mechanism is facilitated by <scene name='83/838655/Bdoxidase_proton_pathways/1'>2 potential proton pathways</scene> via intracellular water molecules. | ||
One potential proton pathway is formed from the <scene name='83/838655/Bdoxidase_helix_a_1-4/1'>four-helix bundle (a1-4)</scene> of CydA. It is called the <scene name='83/838655/Bdoxidase_cyda_pathway_glu108/1'>CydA pathway</scene>. The location of <font color=' | One potential proton pathway is formed from the <scene name='83/838655/Bdoxidase_helix_a_1-4/1'>four-helix bundle (a1-4)</scene> of CydA. It is called the <scene name='83/838655/Bdoxidase_cyda_pathway_glu108/1'>CydA pathway</scene>. The location of <font color='gold'><b>Glu108</b></font> in our structure supports the proposal that this glutamate residue is a redox state-dependent mediator of proton transfer. In other words, its main role is to allow charge to be alleviated at this site. <ref name =”Safarian” /> With the CydA pathway leading to Glu101, this residue could be the protonatable group used for charge compensation upon heme b595 reduction. It is still unknown whether protons entering the CydA pathway can be transferred from Glu101 to Glu378, to allow the spread of the negative charge of a second electron used to reduce the two high-spin hemes. Proto- nation of Glu378 could alternatively also be accomplished by a proton accessing from the extracellular side. More research needs to be done to determine whether the CydA pathway is solely providing protons for charge compensation or whether Glu108 can be a branching point that is able to pass protons via the heme b595 propionates to the oxygen-binding site. | ||
Another potential entry site is related to the a1-4 four-helix bundle of CydB. Therefore, this is called the <scene name='83/838655/Bdoxidase_cydb_pathway/3'>CydB pathway</scene>. In this pathway, Asp25 is thought to be the equivalent of the Glu108 in the CydA pathway <ref name =”Safarian” />. The other residues help facilitate the movement of the proton very similarly to the CydA pathway. There is less known about the CydB pathway, and therefore, the CydA pathway is the most accepted source of protons. | Another potential entry site is related to the a1-4 four-helix bundle of CydB. Therefore, this is called the <scene name='83/838655/Bdoxidase_cydb_pathway/3'>CydB pathway</scene>. In this pathway, Asp25 is thought to be the equivalent of the Glu108 in the CydA pathway <ref name =”Safarian” />. The other residues help facilitate the movement of the proton very similarly to the CydA pathway. There is less known about the CydB pathway, and therefore, the CydA pathway is the most accepted source of protons. | ||
