1rcy
From Proteopedia
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RUSTICYANIN (RC) FROM THIOBACILLUS FERROOXIDANS
Overview
The X-ray crystal structure of the oxidized form of the extremely stable, and highly oxidizing cupredoxin rusticyanin from Thiobacillus ferrooxidans, has been determined by the method of multiwavelength anomalous diffraction, (MAD) and refined to 1.9 A resolution. Like other cupredoxins, rusticyanin, is a copper-containing metalloprotein, which is composed of a core, beta-sandwich fold. In rusticyanin the beta-sandwich is composed of a six-, and a seven-stranded beta-sheet. Also like other cupredoxins, the copper, ion is coordinated by a cluster of four conserved residues (His85, Cys138, His143, Met148) arranged in a distorted tetrahedron. Rusticyanin has a, redox potential of 680 mV, roughly twice that of any other cupredoxin, and, it is optimally active at pH values < or = 2. By comparison with other, cupredoxins, the three-dimensional structure of rusticyanin reveals, several possible sources of the chemical differences, including more, ordered secondary structure and more intersheet connectivity than other, cupredoxins. The acid stability and redox potential of rusticyanin may, also be enhanced over other cupredoxins by a more extensive internal, hydrogen bonding network and by more extensive hydrophobic interactions, surrounding the copper binding site. Finally, reduction in the number of, charged residues surrounding the active site may also make a major, contribution to acid stability. We propose that the resulting rigid copper, binding site, which is constrained by the surrounding hydrophobic, environment, structurally and electronically favours Cu(I). We propose, that the two extreme chemical properties of rusticyanin are interrelated;, the same unique structural features that enhance acid stability also lead, to elevated redox potential.
About this Structure
1RCY is a Single protein structure of sequence from Acidithiobacillus ferrooxidans with CU as ligand. Known structural/functional Site: . Full crystallographic information is available from OCA.
Reference
Multiple wavelength anomalous diffraction (MAD) crystal structure of rusticyanin: a highly oxidizing cupredoxin with extreme acid stability., Walter RL, Ealick SE, Friedman AM, Blake RC 2nd, Proctor P, Shoham M, J Mol Biol. 1996 Nov 15;263(5):730-51. PMID:8947572
Page seeded by OCA on Tue Dec 18 17:59:09 2007
