ABCG2 multidrug transporter: Difference between revisions
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===ATP Bound and Unbound Conformations=== | ===ATP Bound and Unbound Conformations=== | ||
As an [https://en.wikipedia.org/wiki/ATP-binding_cassette_transporter ABC Transporter], ABCG2 exhibits ATPase activity and uses the energy of ATP hydrolysis to facilitate transport. After substrates bind in the TMD, one molecule of <scene name='83/832932/Atp_bound_use2/3'>ATP binds each NBD</scene> (2 molecules of ATP total) causing a conformational change of the overall structure from an <scene name='83/832932/Overall_use_2/3'>inward-facing conformation</scene> to an <scene name='83/832932/Outward_facing_conformation/4'>outward-facing conformation</scene>. <scene name='83/832937/Atp_and_mg_bound_to_abcg2/4'>ATP coordinates</scene> with various residues and a magnesium ion in the <scene name='83/832932/Atp_bound_in_nbd/2'>binding site of each NBD</scene> which is bordered with [https://en.wikipedia.org/wiki/Walker_motifs Walker A and B motifs]. One molecule of ATP is hydrolyzed to transport substrates across the cell membrane while the second molecule of ATP is hydrolyzed to reset the transporter to its inward-facing conformation.<ref name="Robey"/> | As an [https://en.wikipedia.org/wiki/ATP-binding_cassette_transporter ABC Transporter], ABCG2 exhibits ATPase activity and uses the energy of ATP hydrolysis to facilitate transport. After substrates bind in the TMD, one molecule of <scene name='83/832932/Atp_bound_use2/3'>ATP binds each NBD</scene> (2 molecules of ATP total) causing a conformational change of the overall structure from an <scene name='83/832932/Overall_use_2/3'>inward-facing conformation</scene> to an <scene name='83/832932/Outward_facing_conformation/4'>outward-facing conformation</scene> (<scene name='86/869419/Animation/1'>animation</scene>). <scene name='83/832937/Atp_and_mg_bound_to_abcg2/4'>ATP coordinates</scene> with various residues and a magnesium ion in the <scene name='83/832932/Atp_bound_in_nbd/2'>binding site of each NBD</scene> which is bordered with [https://en.wikipedia.org/wiki/Walker_motifs Walker A and B motifs]. One molecule of ATP is hydrolyzed to transport substrates across the cell membrane while the second molecule of ATP is hydrolyzed to reset the transporter to its inward-facing conformation.<ref name="Robey"/> | ||
When ATP binds, α-helices in the NBD <scene name='83/832932/Atp_bound_nbd/3'>rotate</scene> approximately 35° relative to the <scene name='83/832932/Overall_structure_nbd_unbound/5'>inward-facing conformation of NBD</scene>. This shift in the NBD causes slight shifts of α-helices in the TMD; these helices are <scene name='83/832932/Atp_bound_use_tmd/4'>pushed toward each other</scene> relative to the <scene name='83/832932/Overall_structure_tmd_unbound/4'>inward-facing conformation of TMD</scene>. The overall shift from inward-facing to outward-facing promotes the transport of substrates through the transporter.<ref name="Manolaridis"/> | When ATP binds, α-helices in the NBD <scene name='83/832932/Atp_bound_nbd/3'>rotate</scene> approximately 35° relative to the <scene name='83/832932/Overall_structure_nbd_unbound/5'>inward-facing conformation of NBD</scene>. This shift in the NBD causes slight shifts of α-helices in the TMD; these helices are <scene name='83/832932/Atp_bound_use_tmd/4'>pushed toward each other</scene> relative to the <scene name='83/832932/Overall_structure_tmd_unbound/4'>inward-facing conformation of TMD</scene>. The overall shift from inward-facing to outward-facing promotes the transport of substrates through the transporter.<ref name="Manolaridis"/> | ||