Structure clostridial rubredoxin

Iron-sulfur proteins occur in animal, plant, and bacterial cells. The proteins are characterized by the presence of 1-0, 2-2, 4rA, 6-6, or 8-8 atoms of iroursulfide. Only the structure of clostridial rubredoxin, a 1-0 protein, is knoum. It contains iron ligated to four sulfur atoms of cysteine residues of the polypeptide. With the exception of the ""high potential iron protein, all the proteins show unexpectedly low redox potentials and function in biological oxidationr-reduc-tion reactions. 

The complete structure of clostridial rubredoxin has been solved by Jensen and his associates using x-ray analysis (49), and the structure of the iron-sulfur center of the high potential iron protein, but not of the polypeptide, has been determined by x-ray analysis by Kraut and associates (50). Both of these are relatively atypical proteins in this class, either having no inorganic sulfide or having a very high redox potential. So far, we still have no solution from x-ray work for the 2-iron-2-sulfur or the 8-iron-8-sulfur type protein. 

The structure for the clostridial rubredoxin that has been determined by x-ray analysis (49) has clearly shown that the iron is ligated to the four cysteine residues at positions 6, 9, 38, and 41. This involves, of... 

Although we are beginning to build up a structural and electronic picture of the active site of the iron-sulphur proteins, very little is known about their kinetic properties. The rate parameters have recently been reported for the second-order reduction of oxidized clostridial rubredoxin by [Ru(NHs)6] +, Vaq +, and Craq (Table 3). Rubredoxin is the least complex of the Fe-S proteins (mol. wt. ca. 6000 ... 

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