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Sandbox effluxpumps
From Proteopedia
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== Function == | == Function == | ||
| - | Efflux pumps function to move different substances out of cells such as ions, lipids, and molecules that are toxic for the cell. | + | Efflux pumps function to move different substances out of cells such as ions, lipids, and molecules that are toxic for the cell. <ref name= "A Primer on the Mechanics of the Multidrug Transporter">M. Hennessy and J.P. Spiers, “A Primer on the Mechanics of P-glycoprotein the Multidrug Transporter,” Pharmacological Research 55 (2007): 1. </ref> ATP-binding cassette (ABC) transporters are a common class of efflux pumps found in all forms of life. Humans have forty-eight known ABC transporters. An example of an ABC transporter is ABCB6. |
An ATP-switch model for transport has been used to describe ABC transporters. For transport, a switch between two conformations of the nucleotide binding domain dimer serves as the promoter. The binding of ATP induces the rotation of domains within the nucleotide-binding domain. A closed dimer with two molecules of ATP between the dimer is formed. The hydrolysis of ATP into ADP and Pi returns the dimer to an open configuration. The binding of ATP to the nucleotide binding domains and the closed dimer formation induces conformational changes in the transmembrane domains that aid in the movement of substrate out of the cell. The transmembrane domain is shifted so that the domain is visible to the extracellular face of the membrane and the substrates can then be released. Similar to the nucleotide-binding domain, the hydrolysis of ATP to ADP and Pi restores the dimer to its beginning conformation. | An ATP-switch model for transport has been used to describe ABC transporters. For transport, a switch between two conformations of the nucleotide binding domain dimer serves as the promoter. The binding of ATP induces the rotation of domains within the nucleotide-binding domain. A closed dimer with two molecules of ATP between the dimer is formed. The hydrolysis of ATP into ADP and Pi returns the dimer to an open configuration. The binding of ATP to the nucleotide binding domains and the closed dimer formation induces conformational changes in the transmembrane domains that aid in the movement of substrate out of the cell. The transmembrane domain is shifted so that the domain is visible to the extracellular face of the membrane and the substrates can then be released. Similar to the nucleotide-binding domain, the hydrolysis of ATP to ADP and Pi restores the dimer to its beginning conformation. | ||
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[[Image:ABCB6.png | thumb | This is an image of mitochondrial ABC transporter ABCB6]] | [[Image:ABCB6.png | thumb | This is an image of mitochondrial ABC transporter ABCB6]] | ||
| - | One unit of an ATP-binding cassette consists of a nucleotide binding domain and a trans-membrane domain that has six α-helices. Hydrophilic loops and the nucleotide-binding domain separate the α-helices. Two nucleotide-binding domains are responsible for binding to and hydrolyzing ATP. The two transmembrane domains of a functional ABC transporter are used to form the chamber that substrates use to move across the membrane. It is important to note that in ABC transporters the Walker A and B motifs are conserved and have a role in hydrogen bonding to and hydrolyzing ATP, an ABC transporter signature motif. The different motifs in ABC transporters form the ATP binding site. | + | One unit of an ATP-binding cassette consists of a nucleotide binding domain and a trans-membrane domain that has six α-helices. Hydrophilic loops and the nucleotide-binding domain separate the α-helices. <ref name="A Primer on the Mechanics of the Multidrug Transporter" /> Two nucleotide-binding domains are responsible for binding to and hydrolyzing ATP. The two transmembrane domains of a functional ABC transporter are used to form the chamber that substrates use to move across the membrane. It is important to note that in ABC transporters the Walker A and B motifs are conserved and have a role in hydrogen bonding to and hydrolyzing ATP, an ABC transporter signature motif. The different motifs in ABC transporters form the ATP binding site. |
Revision as of 18:52, 9 December 2015
This page is setup for Angela to build her senior project for OU CHEM 4923
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References
- ↑ Hanson, R. M., Prilusky, J., Renjian, Z., Nakane, T. and Sussman, J. L. (2013), JSmol and the Next-Generation Web-Based Representation of 3D Molecular Structure as Applied to Proteopedia. Isr. J. Chem., 53:207-216. doi:http://dx.doi.org/10.1002/ijch.201300024
- ↑ Herraez A. Biomolecules in the computer: Jmol to the rescue. Biochem Mol Biol Educ. 2006 Jul;34(4):255-61. doi: 10.1002/bmb.2006.494034042644. PMID:21638687 doi:10.1002/bmb.2006.494034042644
- ↑ 3.0 3.1 M. Hennessy and J.P. Spiers, “A Primer on the Mechanics of P-glycoprotein the Multidrug Transporter,” Pharmacological Research 55 (2007): 1.
