Sandbox Reserved 1600: Difference between revisions
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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 residues along this pathway help facilitate the movement of the protons. The location of <scene name='83/838655/Bdoxidase_cyda_pathway_glu108/2'>Glu108</scene> in the structure is a key residue in this pathway. Its location within the pathway and negative charge characteristic implies that this glutamate residue is a redox state-dependent mediator of proton transfer. In other words, it acts like a proton shuttle <ref name =”Safarian” />. The <scene name='83/838655/Bdoxidase_cyda_pathway_glu101/1'>Glu101 residue</scene>, which is the last residue in this pathway, could be the protonatable group eventually used upon heme b595 reduction. 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. <ref name=”Safarian”>PMID:27126043</ref> | 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 residues along this pathway help facilitate the movement of the protons. The location of <scene name='83/838655/Bdoxidase_cyda_pathway_glu108/2'>Glu108</scene> in the structure is a key residue in this pathway. Its location within the pathway and negative charge characteristic implies that this glutamate residue is a redox state-dependent mediator of proton transfer. In other words, it acts like a proton shuttle <ref name =”Safarian” />. The <scene name='83/838655/Bdoxidase_cyda_pathway_glu101/1'>Glu101 residue</scene>, which is the last residue in this pathway, could be the protonatable group eventually used upon heme b595 reduction. 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. <ref name=”Safarian”>PMID:27126043</ref> | ||
Another potential entry site is related to the <scene name='83/838655/Bdoxidase_cydb_subunit_b1-4/1'>a1-4 four-helix bundle</scene> 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 <scene name='83/838655/Bdoxidase_cydb_subunit_b1-4/1'>a1-4 four-helix bundle</scene> of CydB. Therefore, this is called the <scene name='83/838655/Bdoxidase_cydb_pathway/3'>CydB pathway</scene>. In this pathway, <scene name='83/838655/Bdoxidase_cydb_pathway_asp25/1'>Asp25</scene> 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. | ||
= Overall Oxygen Reduction Mechanism Summary= | = Overall Oxygen Reduction Mechanism Summary= | ||
