1g6b: Difference between revisions
New page: left|200px<br /><applet load="1g6b" size="450" color="white" frame="true" align="right" spinBox="true" caption="1g6b, resolution 1.90Å" /> '''CRYSTAL STRUCTURE OF... |
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[[Image:1g6b.gif|left|200px]]<br /><applet load="1g6b" size=" | [[Image:1g6b.gif|left|200px]]<br /><applet load="1g6b" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1g6b, resolution 1.90Å" /> | caption="1g6b, resolution 1.90Å" /> | ||
'''CRYSTAL STRUCTURE OF P47S MUTANT OF FERREDOXIN I'''<br /> | '''CRYSTAL STRUCTURE OF P47S MUTANT OF FERREDOXIN I'''<br /> | ||
==Overview== | ==Overview== | ||
The reduction potential (E(0)') of the [4Fe-4S](2+/+) cluster of | The reduction potential (E(0)') of the [4Fe-4S](2+/+) cluster of Azotobacter vinelandii ferredoxin I (AvFdI) and related ferredoxins is approximately 200 mV more negative than the corresponding clusters of Peptostreptococcus asaccharolyticus ferredoxin and related ferredoxins. Previous studies have shown that these differences in E(0)' do not result from the presence or absence of negatively charged surface residues or in differences in the types of hydrophobic residues found close to the [4Fe-4S](2+/+) clusters. Recently, a third, quite distinct class of ferredoxins (represented by the structurally characterized Chromatium vinosum ferredoxin) was shown to have a [4Fe-4S](2+/+) cluster with a very negative E(0)' similar to that of AvFdI. The observation that the sequences and structures surrounding the very negative E(0)' clusters in quite dissimilar proteins were almost identical inspired the construction of three additional mutations in the region of the [4Fe-4S](2+/+) cluster of AvFdI. The three mutations, V19E, P47S, and L44S, that incorporated residues found in the higher E(0)' P. asaccharolyticus ferredoxin all led to increases in E(0)' for a total of 130 mV with a 94-mV increase in the case of L44S. The results are interpreted in terms of x-ray structures of the FdI variants and show that the major determinant for the large increase in L44S is the introduction of an OH-S bond between the introduced Ser side chain and the Sgamma atom of Cys ligand 42 and an accompanying movement of water. | ||
==About this Structure== | ==About this Structure== | ||
1G6B 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:// | 1G6B 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=1G6B OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Azotobacter vinelandii]] | [[Category: Azotobacter vinelandii]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Bonagura, C | [[Category: Bonagura, C A.]] | ||
[[Category: Burgess, B | [[Category: Burgess, B K.]] | ||
[[Category: Jung, Y | [[Category: Jung, Y S.]] | ||
[[Category: Stout, C | [[Category: Stout, C D.]] | ||
[[Category: F3S]] | [[Category: F3S]] | ||
[[Category: SF4]] | [[Category: SF4]] | ||
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[[Category: iron-sulfur clusters]] | [[Category: iron-sulfur clusters]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:46:35 2008'' | ||
Revision as of 13:46, 21 February 2008
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CRYSTAL STRUCTURE OF P47S MUTANT OF FERREDOXIN I
OverviewOverview
The reduction potential (E(0)') of the [4Fe-4S](2+/+) cluster of Azotobacter vinelandii ferredoxin I (AvFdI) and related ferredoxins is approximately 200 mV more negative than the corresponding clusters of Peptostreptococcus asaccharolyticus ferredoxin and related ferredoxins. Previous studies have shown that these differences in E(0)' do not result from the presence or absence of negatively charged surface residues or in differences in the types of hydrophobic residues found close to the [4Fe-4S](2+/+) clusters. Recently, a third, quite distinct class of ferredoxins (represented by the structurally characterized Chromatium vinosum ferredoxin) was shown to have a [4Fe-4S](2+/+) cluster with a very negative E(0)' similar to that of AvFdI. The observation that the sequences and structures surrounding the very negative E(0)' clusters in quite dissimilar proteins were almost identical inspired the construction of three additional mutations in the region of the [4Fe-4S](2+/+) cluster of AvFdI. The three mutations, V19E, P47S, and L44S, that incorporated residues found in the higher E(0)' P. asaccharolyticus ferredoxin all led to increases in E(0)' for a total of 130 mV with a 94-mV increase in the case of L44S. The results are interpreted in terms of x-ray structures of the FdI variants and show that the major determinant for the large increase in L44S is the introduction of an OH-S bond between the introduced Ser side chain and the Sgamma atom of Cys ligand 42 and an accompanying movement of water.
About this StructureAbout this Structure
1G6B is a Single protein structure of sequence from Azotobacter vinelandii with and as ligands. Full crystallographic information is available from OCA.
ReferenceReference
Azotobacter vinelandii ferredoxin I: a sequence and structure comparison approach to alteration of [4Fe-4S]2+/+ reduction potential., Chen K, Jung YS, Bonagura CA, Tilley GJ, Prasad GS, Sridhar V, Armstrong FA, Stout CD, Burgess BK, J Biol Chem. 2002 Feb 15;277(7):5603-10. Epub 2001 Nov 9. PMID:11704670
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