The Nuclear Magnetic Resonance Solution Structure of the Mixed Disulfide between Escherichia coli Glutaredoxin(C14S) and Glutathione

The NMR solution structure of human glutaredoxin in the fully reduced form

“…Both this hydrogen bond and the previous one are located in close proximity to the site of binding of glutathione (Bushweller et al, 1994) and of ribonucleotide reductase (Berardi et al, 1998) identi®ed in E. coli glutaredoxin-1, suggesting that their presence or absence could be in¯uenced by substrate binding and could provide a mechanism for conformational changes associated with binding. Helices 4 and 5 are bent at an angle of approximately 90 to one another.…”

“…As seen in Figure 3, human glutaredoxin is an a/b protein as are all the other glutaredoxins for which structural information is available (Sodano et al, 1991;Xia et al, 1992;Bushweller et al, 1994;Eklund et al, 1992;Ingelman et al, 1995;Katti et al, 1995). The molecular architecture of human glutaredoxin consists of a four-stranded mixed b-sheet very similar to that observed in E. coli glutaredoxin-1 (Sodano et al, 1991) composed of residues 15 to 19, 43 to 47, 72 to 75, and 78 to 81 and ®ve a-helices composed of residues 4 to 9, 24 to 34, 54 to 65, 83 to 91, and 94 to 100 in contrast to the three helices observed in E. coli glutaredoxin-1.…”

“…In addition, a-helix 4 in human glutaredoxin is replaced by an extended secondary structure element in human thioredoxin. This is likely to be functionally important since corresponding residues in this helix have been implicated in the binding of glutathione (Bushweller et al, 1994) as well as ribonucleotide reductase (Berardi et al, 1998) to E. coli glutaredoxin-1. The removal of this helix creates a much less tortuous surface than that found in glutaredoxins which may help to explain the enhanced substrate speci®city glutaredoxins display relative to thioredoxins which are quite general protein disul®de reductases.…”

“…They have also been shown to play a role in the reduction of sulfate (Russel et al, 1990;Tsang, 1981), arsenate (Gladysheva et al, 1994;Wells et al, 1990), and ascorbate (Ahn & Moss, 1992;Gravina & Mieyal, 1993). They preferentially reduce glutathione-containing mixed disul®des (Gravina & Mieyal, 1993;Jung & Thomsa, 1996) due to the glutathione binding site present on the protein (Bushweller et al, 1994) . This preference for GSH-containing mixed disul®des also means that these proteins will play a key role in the glutathionylation and deglutathionylation of proteins which is an important element of the cellular response to oxidative stress.…”

“…In E. coli, both thioredoxin and glutaredoxin can function as an effective protein disul®de reductant for ribonucleotide reductase; however, mutants de®cient in Grx (Kren et al, 1988) and the tenfold lower K m value of Grx for ribonucleotide reductase (Holmgren, 1979) suggest that Grx may be the dominant in vivo reductant. Three-dimensional structures of a number of glutaredoxins have recently been determined including for the oxidized, reduced, and GSH mixed disul®de forms of E. coli glutaredoxin-1 (Sodano et al, 1991;Xia et al, 1992;Bushweller et al, 1994), for the oxidized and reduced forms of bacteriophage T4 glutaredoxins (Eklund et al, 1992;Ingelman et al, 1995), and for oxidized pig liver glutaredoxin (Katti et al, 1995).…”