Cyanide mediated conformational changes resulted in the displacement of sulfate ion from the active site of bovine pancreatic ribonuclease A

Ribonuclease A is a major hydrolyzing enzyme involved in the hydrolysis of RNA. The crystals of bovine pancreatic RNase A (bpRNase A) were grown at pH 5.5. The effect of sodium cyanide on bpRNase A was assessed by adding it directly to the crystal containing well. Treating the crystals of bpRNase A with sodium cyanide resulted in the displacement of the sulfate ion from the active site of bpRNase A, while the additional sulfate ion, bound to Ala-4, remained unaffected. The addition of sodium cyanide to bpRNase A crystals did not show change in the secondary structure elements of the enzyme. This study was conducted to check the effect of cyanide on bpRNase A crystals and to displace sulfate ion from its active site.