1zjl
From Proteopedia
(New page: 200px<br /><applet load="1zjl" size="450" color="white" frame="true" align="right" spinBox="true" caption="1zjl, resolution 2.00Å" /> '''Crystal structure of...) |
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| - | [[Image:1zjl.gif|left|200px]]<br /><applet load="1zjl" size=" | + | [[Image:1zjl.gif|left|200px]]<br /><applet load="1zjl" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1zjl, resolution 2.00Å" /> | caption="1zjl, resolution 2.00Å" /> | ||
'''Crystal structure of zinc-bound engineered maltose binding protein'''<br /> | '''Crystal structure of zinc-bound engineered maltose binding protein'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Protein engineering was used previously to convert maltose-binding protein | + | Protein engineering was used previously to convert maltose-binding protein (MBP) into a zinc biosensor. Zn(2+) binding by the engineered MBP was thought to require a large conformational change from "open" to "closed", similar to that observed when maltose is bound by the wild-type protein. We show that although this re-designed MBP molecule binds Zn(2+) with high affinity as previously reported, it does not adopt a closed conformation in solution as assessed by small-angle X-ray scattering. High-resolution crystallographic studies of the engineered Zn(2+)-binding MBP molecule demonstrate that Zn(2+) is coordinated by residues on the N-terminal lobe only, and therefore Zn(2+) binding does not require the protein to adopt a fully closed conformation. Additional crystallographic studies indicate that this unexpected Zn(2+) binding site can also coordinate Cu(2+) and Ni(2+) with only subtle changes in the overall conformation of the protein. This work illustrates that the energetic barrier to domain closure, which normally functions to maintain MBP in an open concentration in the absence of ligand, is not easily overcome by protein design. A comparison to the mechanism of maltose-induced domain rearrangement is discussed. |
==About this Structure== | ==About this Structure== | ||
| - | 1ZJL is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with ZN as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1ZJL is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=ZN:'>ZN</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ZJL OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Shilton, B | + | [[Category: Shilton, B H.]] |
| - | [[Category: Telmer, P | + | [[Category: Telmer, P G.]] |
[[Category: ZN]] | [[Category: ZN]] | ||
[[Category: abc transport]] | [[Category: abc transport]] | ||
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[[Category: zinc-binding mutant]] | [[Category: zinc-binding mutant]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:16:15 2008'' |
Revision as of 14:16, 21 February 2008
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Crystal structure of zinc-bound engineered maltose binding protein
Overview
Protein engineering was used previously to convert maltose-binding protein (MBP) into a zinc biosensor. Zn(2+) binding by the engineered MBP was thought to require a large conformational change from "open" to "closed", similar to that observed when maltose is bound by the wild-type protein. We show that although this re-designed MBP molecule binds Zn(2+) with high affinity as previously reported, it does not adopt a closed conformation in solution as assessed by small-angle X-ray scattering. High-resolution crystallographic studies of the engineered Zn(2+)-binding MBP molecule demonstrate that Zn(2+) is coordinated by residues on the N-terminal lobe only, and therefore Zn(2+) binding does not require the protein to adopt a fully closed conformation. Additional crystallographic studies indicate that this unexpected Zn(2+) binding site can also coordinate Cu(2+) and Ni(2+) with only subtle changes in the overall conformation of the protein. This work illustrates that the energetic barrier to domain closure, which normally functions to maintain MBP in an open concentration in the absence of ligand, is not easily overcome by protein design. A comparison to the mechanism of maltose-induced domain rearrangement is discussed.
About this Structure
1ZJL is a Single protein structure of sequence from Escherichia coli with as ligand. Full crystallographic information is available from OCA.
Reference
Structural studies of an engineered zinc biosensor reveal an unanticipated mode of zinc binding., Telmer PG, Shilton BH, J Mol Biol. 2005 Dec 9;354(4):829-40. Epub 2005 Oct 28. PMID:16288781
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