1c09

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spinqualitylabelsall models 1c09, resolution 1.6Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

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 FE 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 Tue Nov 20 12:03:29 2007