1s98
From Proteopedia
(New page: 200px<br /><applet load="1s98" size="450" color="white" frame="true" align="right" spinBox="true" caption="1s98, resolution 2.30Å" /> '''E.coli IscA crystal ...) |
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| - | [[Image:1s98.gif|left|200px]]<br /><applet load="1s98" size=" | + | [[Image:1s98.gif|left|200px]]<br /><applet load="1s98" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1s98, resolution 2.30Å" /> | caption="1s98, resolution 2.30Å" /> | ||
'''E.coli IscA crystal structure to 2.3 A'''<br /> | '''E.coli IscA crystal structure to 2.3 A'''<br /> | ||
==Overview== | ==Overview== | ||
| - | IscA, an 11 kDa member of the hesB family of proteins, binds iron and | + | IscA, an 11 kDa member of the hesB family of proteins, binds iron and [2Fe-2S] clusters, and participates in the biosynthesis of iron-sulfur proteins. We report the crystal structure of the apo-protein form of IscA from Escherichia coli to a resolution of 2.3A. The crystals belong to the space group P3(2)21 and have unit cell dimensions a=b=66.104 A, c=150.167 A (alpha=beta=90 degrees, gamma=120 degrees ). The structure was solved using single-wavelength anomalous dispersion (SAD) phasing of a selenomethionyl derivative, and the IscA model was refined to R=21.4% (Rfree=25.4%). IscA exists as an (alpha1alpha2)2 homotetramer with the (alpha1alpha2) dimer comprising the asymmetric unit. Cys35, implicated in Fe-S cluster assembly, is located in a central cavity formed at the tetramer interface with the gamma-sulfur atoms of residues from the alpha1 and alpha2' monomers (and alpha1'alpha2) positioned close to one another (approximately equal 7 A). C-terminal residues 99-107 are disordered, and the exact positions of Cys99 and Cys101 could not be determined. However, computer modeling of C-terminal residues in the tetramer suggests that Cys99 and Cys101 in the alpha1 monomer and those of the alpha1' monomer (or alpha2 and alpha2') are positioned sufficiently close to coordinate [2Fe-2S] clusters between the two dimers, whereas this is not possible within the (alpha1alpha2) or (alpha1'alpha2') dimer. This symmetrical arrangement allows for binding of two [2Fe-2S] clusters on opposite sides of the tetramer. Modeling further reveals that Cys101 is positioned sufficiently close to Cys35 to allow Cys35 to participate in cluster assembly, formation, or transfer. |
==About this Structure== | ==About this Structure== | ||
| - | 1S98 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:// | + | 1S98 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=1S98 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Cupp-Vickery, J | + | [[Category: Cupp-Vickery, J R.]] |
| - | [[Category: Silberg, J | + | [[Category: Silberg, J J.]] |
| - | [[Category: Ta, D | + | [[Category: Ta, D T.]] |
| - | [[Category: Vickery, L | + | [[Category: Vickery, L E.]] |
[[Category: fe-s cluster]] | [[Category: fe-s cluster]] | ||
[[Category: iron]] | [[Category: iron]] | ||
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[[Category: sulfur]] | [[Category: sulfur]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:59:08 2008'' |
Revision as of 12:59, 21 February 2008
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E.coli IscA crystal structure to 2.3 A
Overview
IscA, an 11 kDa member of the hesB family of proteins, binds iron and [2Fe-2S] clusters, and participates in the biosynthesis of iron-sulfur proteins. We report the crystal structure of the apo-protein form of IscA from Escherichia coli to a resolution of 2.3A. The crystals belong to the space group P3(2)21 and have unit cell dimensions a=b=66.104 A, c=150.167 A (alpha=beta=90 degrees, gamma=120 degrees ). The structure was solved using single-wavelength anomalous dispersion (SAD) phasing of a selenomethionyl derivative, and the IscA model was refined to R=21.4% (Rfree=25.4%). IscA exists as an (alpha1alpha2)2 homotetramer with the (alpha1alpha2) dimer comprising the asymmetric unit. Cys35, implicated in Fe-S cluster assembly, is located in a central cavity formed at the tetramer interface with the gamma-sulfur atoms of residues from the alpha1 and alpha2' monomers (and alpha1'alpha2) positioned close to one another (approximately equal 7 A). C-terminal residues 99-107 are disordered, and the exact positions of Cys99 and Cys101 could not be determined. However, computer modeling of C-terminal residues in the tetramer suggests that Cys99 and Cys101 in the alpha1 monomer and those of the alpha1' monomer (or alpha2 and alpha2') are positioned sufficiently close to coordinate [2Fe-2S] clusters between the two dimers, whereas this is not possible within the (alpha1alpha2) or (alpha1'alpha2') dimer. This symmetrical arrangement allows for binding of two [2Fe-2S] clusters on opposite sides of the tetramer. Modeling further reveals that Cys101 is positioned sufficiently close to Cys35 to allow Cys35 to participate in cluster assembly, formation, or transfer.
About this Structure
1S98 is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Crystal structure of IscA, an iron-sulfur cluster assembly protein from Escherichia coli., Cupp-Vickery JR, Silberg JJ, Ta DT, Vickery LE, J Mol Biol. 2004 Apr 16;338(1):127-37. PMID:15050828
Page seeded by OCA on Thu Feb 21 14:59:08 2008
Categories: Escherichia coli | Single protein | Cupp-Vickery, J R. | Silberg, J J. | Ta, D T. | Vickery, L E. | Fe-s cluster | Iron | Isc | Isca | Sulfur
