User:Jessica Klingensmith/Sandbox 1068
From Proteopedia
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==Zinc Transporter YiiP== 2 | ==Zinc Transporter YiiP== 2 | ||
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== Introduction == | == Introduction == | ||
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Zinc transporter YiiP is an integral membrane protein found in the membrane of Esherichia coli. YiiP is a member of the cation diffusion facilitator family (LINK). Members of this family occur all throughout the biological realm. These diffusion facilitators export divalent transition metal ions from the cytoplasm to the extracellular space (CITE https://www.bnl.gov/isd/documents/71335.pdf). They work to regulate the amount of divalent metals inside of the cell, which is biologically relevant because while these metals are necessary for different biological functions, they can prove fatal to the cell in excess amounts. Zinc is essential for the growth and development of cells and zinc levels can affect everything from gene expression to immune response. Zinc transporters help keep homeostatic balance of zinc in cells and excessive zinc concentrations have been noted in cases of high beta-amyloid deposition contributing to Alzheimer's disease (CITE: http://science.sciencemag.org/content/317/5845/1746.full While YiiP is an integral membrane protein in the cells of Escherichia coli, understanding the mechanism of regulation behind it can help researcher's better understand the CDF equivalents in eukaryotic cells. | Zinc transporter YiiP is an integral membrane protein found in the membrane of Esherichia coli. YiiP is a member of the cation diffusion facilitator family (LINK). Members of this family occur all throughout the biological realm. These diffusion facilitators export divalent transition metal ions from the cytoplasm to the extracellular space (CITE https://www.bnl.gov/isd/documents/71335.pdf). They work to regulate the amount of divalent metals inside of the cell, which is biologically relevant because while these metals are necessary for different biological functions, they can prove fatal to the cell in excess amounts. Zinc is essential for the growth and development of cells and zinc levels can affect everything from gene expression to immune response. Zinc transporters help keep homeostatic balance of zinc in cells and excessive zinc concentrations have been noted in cases of high beta-amyloid deposition contributing to Alzheimer's disease (CITE: http://science.sciencemag.org/content/317/5845/1746.full While YiiP is an integral membrane protein in the cells of Escherichia coli, understanding the mechanism of regulation behind it can help researcher's better understand the CDF equivalents in eukaryotic cells. | ||
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== Structure == | == Structure == | ||
| - | YiiP is a homodimer with each | + | YiiP is a homodimer with each protomer consisting of 238 residues. YiiP has a "Y" shape <scene name='75/756372/Newmainpic/1'> conformation</scene> with two different functional conformations. A total of six helices comprise the transmembrane portion of each <scene name='75/756372/Sixhelices/1'>protomer</scene>. Four of these helices are bundled together while the remaining two are oriented antiparallel to the <scene name='75/756372/2antiparallel/1'>bundle</scene>. Movement of these helices play a role in the function of YiiP. An interlocked salt bridge connects the two domains with the Lys77 and the Asp207 from each protomer - visualized <scene name='75/756372/Saltbridgeclose/1'>here</scene>.This salt bridge acts as the hinge for the conformational changes that YiiP undergoes.<scene name='75/756372/Hydrophobic1/1'>Hydrophobic</scene> residues beneath the salt bridge further stabilize the two domains in the v-shaped void where the domains connect. YiiP has three zinc binding sites, two of which are known to play an active role in the function of YiiP. Site A (link) sits in extracellular space outside of the cell, while site C is situated inside of the cell to act as a sensor of intracellular zinc concentrations. |
=== Structural highlights === | === Structural highlights === | ||
====Interlocking Salt Bridge==== | ====Interlocking Salt Bridge==== | ||
| - | The salt bridge formation between Lys77 and Asp207 of each domain of YiiP form an interlocking salt bridge that acts as the pivot point of the conformational change that drives the function of YiiP. | + | The salt bridge formation between Lys77 and Asp207 of each domain of YiiP form an interlocking salt bridge that acts as the pivot point of the conformational change that drives the function of YiiP. The salt bridge is disrupted when Zinc is bound, due to movement of the antiparallel helices. This disrupts the ion-ion attractions that established the salt bridge- causing a conformational shift in YiiP. This salt bridge also aids in holding the two protomers together. [[Image:Saltbridge.png|200px|left|thumb|Lys77 and Asp207 Salt Bridges]] |
====Active Sites==== | ====Active Sites==== | ||
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YiiP functions to export zinc out of the cytoplasm of cells in order to regulate zinc levels within the cell. YiiP works via secondary transport and two conformations to sense zinc in the cell and transport zinc out of the cell into extracellular space using an electrochemical gradient of H+ ins antiported with zinc. The presence of cytoplasmic zinc (bound in the c-terminus domain) activates conformational changes that translocate the metal ions across the membrane and out of the cell. | YiiP functions to export zinc out of the cytoplasm of cells in order to regulate zinc levels within the cell. YiiP works via secondary transport and two conformations to sense zinc in the cell and transport zinc out of the cell into extracellular space using an electrochemical gradient of H+ ins antiported with zinc. The presence of cytoplasmic zinc (bound in the c-terminus domain) activates conformational changes that translocate the metal ions across the membrane and out of the cell. | ||
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</StructureSection> | </StructureSection> | ||
== References == | == References == | ||
<references/> | <references/> | ||
Revision as of 18:23, 24 March 2017
==Zinc Transporter YiiP== 2
Introduction
Zinc transporter YiiP is an integral membrane protein found in the membrane of Esherichia coli. YiiP is a member of the cation diffusion facilitator family (LINK). Members of this family occur all throughout the biological realm. These diffusion facilitators export divalent transition metal ions from the cytoplasm to the extracellular space (CITE https://www.bnl.gov/isd/documents/71335.pdf). They work to regulate the amount of divalent metals inside of the cell, which is biologically relevant because while these metals are necessary for different biological functions, they can prove fatal to the cell in excess amounts. Zinc is essential for the growth and development of cells and zinc levels can affect everything from gene expression to immune response. Zinc transporters help keep homeostatic balance of zinc in cells and excessive zinc concentrations have been noted in cases of high beta-amyloid deposition contributing to Alzheimer's disease (CITE: http://science.sciencemag.org/content/317/5845/1746.full While YiiP is an integral membrane protein in the cells of Escherichia coli, understanding the mechanism of regulation behind it can help researcher's better understand the CDF equivalents in eukaryotic cells.
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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
