1a6l
From Proteopedia
(New page: 200px<br /><applet load="1a6l" size="450" color="white" frame="true" align="right" spinBox="true" caption="1a6l, resolution 2.10Å" /> '''T14C MUTANT OF AZOTO...) |
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| - | [[Image:1a6l.gif|left|200px]]<br /><applet load="1a6l" size=" | + | [[Image:1a6l.gif|left|200px]]<br /><applet load="1a6l" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1a6l, resolution 2.10Å" /> | caption="1a6l, resolution 2.10Å" /> | ||
'''T14C MUTANT OF AZOTOBACTER VINELANDII FDI'''<br /> | '''T14C MUTANT OF AZOTOBACTER VINELANDII FDI'''<br /> | ||
==Overview== | ==Overview== | ||
| - | [4Fe-4S]2+/+ clusters that are ligated by Cys-X-X-Cys-X-X-Cys sequence | + | [4Fe-4S]2+/+ clusters that are ligated by Cys-X-X-Cys-X-X-Cys sequence motifs share the general feature of being hard to convert to [3Fe-4S]+/0 clusters, whereas those that contain a Cys-X-X-Asp-X-X-Cys motif undergo facile and reversible cluster interconversion. Little is known about the factors that control the in vivo assembly and conversion of these clusters. In this study we have designed and constructed a 3Fe to 4Fe cluster conversion variant of Azotobacter vinelandii ferredoxin I (FdI) in which the sequence that ligates the [3Fe-4S] cluster in native FdI was altered by converting a nearby residue, Thr-14, to Cys. Spectroscopic and electrochemical characterization shows that when purified in the presence of dithionite, T14C FdI is an O2-sensitive 8Fe protein. Both the new and the indigenous clusters have reduction potentials that are significantly shifted compared with those in native FdI, strongly suggesting a significantly altered environment around the clusters. Interestingly, whole cell EPR have revealed that T14C FdI exists as a 7Fe protein in vivo. This 7Fe form of T14C FdI is extremely similar to native FdI in its spectroscopic, electrochemical, and structural features. However, unlike native FdI which does not undergo facile cluster conversion, the 7Fe form T14C FdI quickly converts to the 8Fe form with a high efficiency under reducing conditions. |
==About this Structure== | ==About this Structure== | ||
| - | 1A6L is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Azotobacter_vinelandii Azotobacter vinelandii] with SF4 and F3S as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1A6L is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Azotobacter_vinelandii Azotobacter vinelandii] with <scene name='pdbligand=SF4:'>SF4</scene> and <scene name='pdbligand=F3S:'>F3S</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1A6L OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Azotobacter vinelandii]] | [[Category: Azotobacter vinelandii]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Armstrong, F | + | [[Category: Armstrong, F A.]] |
| - | [[Category: Burgess, B | + | [[Category: Burgess, B K.]] |
| - | [[Category: Gao-Sheridan, H | + | [[Category: Gao-Sheridan, H S.]] |
| - | [[Category: Kemper, M | + | [[Category: Kemper, M A.]] |
[[Category: Khayat, R.]] | [[Category: Khayat, R.]] | ||
| - | [[Category: Prasad, G | + | [[Category: Prasad, G S.]] |
[[Category: Sridhar, V.]] | [[Category: Sridhar, V.]] | ||
| - | [[Category: Stout, C | + | [[Category: Stout, C D.]] |
[[Category: F3S]] | [[Category: F3S]] | ||
[[Category: SF4]] | [[Category: SF4]] | ||
| Line 26: | Line 26: | ||
[[Category: iron-sulfur]] | [[Category: iron-sulfur]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:41:25 2008'' |
Revision as of 09:41, 21 February 2008
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T14C MUTANT OF AZOTOBACTER VINELANDII FDI
Overview
[4Fe-4S]2+/+ clusters that are ligated by Cys-X-X-Cys-X-X-Cys sequence motifs share the general feature of being hard to convert to [3Fe-4S]+/0 clusters, whereas those that contain a Cys-X-X-Asp-X-X-Cys motif undergo facile and reversible cluster interconversion. Little is known about the factors that control the in vivo assembly and conversion of these clusters. In this study we have designed and constructed a 3Fe to 4Fe cluster conversion variant of Azotobacter vinelandii ferredoxin I (FdI) in which the sequence that ligates the [3Fe-4S] cluster in native FdI was altered by converting a nearby residue, Thr-14, to Cys. Spectroscopic and electrochemical characterization shows that when purified in the presence of dithionite, T14C FdI is an O2-sensitive 8Fe protein. Both the new and the indigenous clusters have reduction potentials that are significantly shifted compared with those in native FdI, strongly suggesting a significantly altered environment around the clusters. Interestingly, whole cell EPR have revealed that T14C FdI exists as a 7Fe protein in vivo. This 7Fe form of T14C FdI is extremely similar to native FdI in its spectroscopic, electrochemical, and structural features. However, unlike native FdI which does not undergo facile cluster conversion, the 7Fe form T14C FdI quickly converts to the 8Fe form with a high efficiency under reducing conditions.
About this Structure
1A6L is a Single protein structure of sequence from Azotobacter vinelandii with and as ligands. Full crystallographic information is available from OCA.
Reference
A T14C variant of Azotobacter vinelandii ferredoxin I undergoes facile [3Fe-4S]0 to [4Fe-4S]2+ conversion in vitro but not in vivo., Gao-Sheridan HS, Kemper MA, Khayat R, Tilley GJ, Armstrong FA, Sridhar V, Prasad GS, Stout CD, Burgess BK, J Biol Chem. 1998 Dec 11;273(50):33692-701. PMID:9837955
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