1c09
From Proteopedia
(New page: 200px<br /><applet load="1c09" size="450" color="white" frame="true" align="right" spinBox="true" caption="1c09, resolution 1.6Å" /> '''RUBREDOXIN V44A CP'''...) |
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| - | [[Image:1c09.gif|left|200px]]<br /><applet load="1c09" size=" | + | [[Image:1c09.gif|left|200px]]<br /><applet load="1c09" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1c09, resolution 1.6Å" /> | caption="1c09, resolution 1.6Å" /> | ||
'''RUBREDOXIN V44A CP'''<br /> | '''RUBREDOXIN V44A CP'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Rubredoxins (Rds) may be separated into two classes based upon the | + | Rubredoxins (Rds) may be separated into two classes based upon the correlation of their reduction potentials with the identity of residue 44; those with Ala44 have reduction potentials that are approximately 50 mV higher than those with Val44. The smaller side chain volume occupied by Ala44 relative to that occupied by Val44 has been proposed to explain the increase in the reduction potential, based upon changes in the Gly43-Ala44 peptide bond orientation and the distance to the [Fe(SCys)(4)] center in the Pyrococcus furiosus (Pf) Rd crystal structure compared to those of Gly43-Val44 in the Clostridium pasteurianum (Cp) Rd crystal structure. As an experimental test of this hypothesis, single-site Val44 <--> Ala44 exchange mutants, [V44A]Cp and [A44V]Pf Rds, have been cloned and expressed. Reduction potentials of these residue 44 variants and pertinent features of the X-ray crystal structure of [V44A]Cp Rd are reported. Relative to those of wild-type Cp and Pf Rds, the V44A mutation in Cp Rd results in an 86 mV increase in midpoint reduction potential and the [A44V] mutation in Pf Rd results in a 95 mV decrease in midpoint reduction potential, respectively. In the crystal structure of [V44A]Cp Rd, the peptide bond between residues 43 and 44 is approximately 0.3 A closer to the Fe center and the hydrogen bond distance between the residue 44 peptide nitrogen and the Cys42 gamma-sulfur decreases by 0.32 A compared to the analogous distances in the wild-type Cp Rd crystal structure. The results described herein support the prediction that the identity of residue 44 alone determines whether a Rd reduction potential of about -50 or 0 mV is observed. |
==About this Structure== | ==About this Structure== | ||
| - | 1C09 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Clostridium_pasteurianum Clostridium pasteurianum] with FE as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1C09 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Clostridium_pasteurianum Clostridium pasteurianum] with <scene name='pdbligand=FE:'>FE</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1C09 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: metal-binding]] | [[Category: metal-binding]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:01:04 2008'' |
Revision as of 10:01, 21 February 2008
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RUBREDOXIN V44A CP
Overview
Rubredoxins (Rds) may be separated into two classes based upon the correlation of their reduction potentials with the identity of residue 44; those with Ala44 have reduction potentials that are approximately 50 mV higher than those with Val44. The smaller side chain volume occupied by Ala44 relative to that occupied by Val44 has been proposed to explain the increase in the reduction potential, based upon changes in the Gly43-Ala44 peptide bond orientation and the distance to the [Fe(SCys)(4)] center in the Pyrococcus furiosus (Pf) Rd crystal structure compared to those of Gly43-Val44 in the Clostridium pasteurianum (Cp) Rd crystal structure. As an experimental test of this hypothesis, single-site Val44 <--> Ala44 exchange mutants, [V44A]Cp and [A44V]Pf Rds, have been cloned and expressed. Reduction potentials of these residue 44 variants and pertinent features of the X-ray crystal structure of [V44A]Cp Rd are reported. Relative to those of wild-type Cp and Pf Rds, the V44A mutation in Cp Rd results in an 86 mV increase in midpoint reduction potential and the [A44V] mutation in Pf Rd results in a 95 mV decrease in midpoint reduction potential, respectively. In the crystal structure of [V44A]Cp Rd, the peptide bond between residues 43 and 44 is approximately 0.3 A closer to the Fe center and the hydrogen bond distance between the residue 44 peptide nitrogen and the Cys42 gamma-sulfur decreases by 0.32 A compared to the analogous distances in the wild-type Cp Rd crystal structure. The results described herein support the prediction that the identity of residue 44 alone determines whether a Rd reduction potential of about -50 or 0 mV is observed.
About this Structure
1C09 is a Single protein structure of sequence from Clostridium pasteurianum with as ligand. Full crystallographic information is available from OCA.
Reference
Modulation of the redox potential of the [Fe(SCys)(4)] site in rubredoxin by the orientation of a peptide dipole., Eidsness MK, Burden AE, Richie KA, Kurtz DM Jr, Scott RA, Smith ET, Ichiye T, Beard B, Min T, Kang C, Biochemistry. 1999 Nov 9;38(45):14803-9. PMID:10555962
Page seeded by OCA on Thu Feb 21 12:01:04 2008
Categories: Clostridium pasteurianum | Single protein | Beard, B. | Kang, C. | Min, T. | FE | 3d-structure | Iron | Metal-binding
