1uiu
From Proteopedia
(New page: 200px<br /><applet load="1uiu" size="450" color="white" frame="true" align="right" spinBox="true" caption="1uiu, resolution 1.85Å" /> '''Crystal structures o...) |
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| - | [[Image:1uiu.jpg|left|200px]]<br /><applet load="1uiu" size=" | + | [[Image:1uiu.jpg|left|200px]]<br /><applet load="1uiu" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1uiu, resolution 1.85Å" /> | caption="1uiu, resolution 1.85Å" /> | ||
'''Crystal structures of the liganded and unliganded nickel binding protein NikA from Escherichia coli (Nickel unliganded form)'''<br /> | '''Crystal structures of the liganded and unliganded nickel binding protein NikA from Escherichia coli (Nickel unliganded form)'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Bacteria have evolved a number of tightly controlled import and export | + | Bacteria have evolved a number of tightly controlled import and export systems to maintain intracellular levels of the essential but potentially toxic metal nickel. Nickel homeostasis systems include the dedicated nickel uptake system nik found in Escherichia coli, a member of the ABC family of transporters, that involves a periplasmic nickel-binding protein, NikA. This is the initial nickel receptor and mediator of the chemotactic response away from nickel. We have solved the crystal structure of NikA protein in the presence and absence of nickel, showing that it behaves as a "classical" periplasmic binding protein. In contrast to other binding proteins, however, the ligand remains accessible to the solvent and is not completely enclosed. No direct bonds are formed between the metal cation and the protein. The nickel binding site is apolar, quite unlike any previously characterized protein nickel binding site. Despite relatively weak binding, NikA is specific for nickel. Using isothermal titration calorimetry, the dissociation constant for nickel was found to be approximately 10 microm and that for cobalt was approximately 20 times higher. |
==About this Structure== | ==About this Structure== | ||
| - | 1UIU is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http:// | + | 1UIU is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1UIU OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Heddle, J.]] | [[Category: Heddle, J.]] | ||
| - | [[Category: Park, S | + | [[Category: Park, S Y.]] |
| - | [[Category: Scott, D | + | [[Category: Scott, D J.]] |
| - | [[Category: Tame, J | + | [[Category: Tame, J R.H.]] |
[[Category: Unzai, S.]] | [[Category: Unzai, S.]] | ||
[[Category: crytsal structure]] | [[Category: crytsal structure]] | ||
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[[Category: nickel unliganded form]] | [[Category: nickel unliganded form]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:24:57 2008'' |
Revision as of 13:24, 21 February 2008
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Crystal structures of the liganded and unliganded nickel binding protein NikA from Escherichia coli (Nickel unliganded form)
Overview
Bacteria have evolved a number of tightly controlled import and export systems to maintain intracellular levels of the essential but potentially toxic metal nickel. Nickel homeostasis systems include the dedicated nickel uptake system nik found in Escherichia coli, a member of the ABC family of transporters, that involves a periplasmic nickel-binding protein, NikA. This is the initial nickel receptor and mediator of the chemotactic response away from nickel. We have solved the crystal structure of NikA protein in the presence and absence of nickel, showing that it behaves as a "classical" periplasmic binding protein. In contrast to other binding proteins, however, the ligand remains accessible to the solvent and is not completely enclosed. No direct bonds are formed between the metal cation and the protein. The nickel binding site is apolar, quite unlike any previously characterized protein nickel binding site. Despite relatively weak binding, NikA is specific for nickel. Using isothermal titration calorimetry, the dissociation constant for nickel was found to be approximately 10 microm and that for cobalt was approximately 20 times higher.
About this Structure
1UIU is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Crystal structures of the liganded and unliganded nickel-binding protein NikA from Escherichia coli., Heddle J, Scott DJ, Unzai S, Park SY, Tame JR, J Biol Chem. 2003 Dec 12;278(50):50322-9. Epub 2003 Sep 5. PMID:12960164
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