Raman spectroscopic study of the interaction between sulfate anion and an imidazolium ring in ribonuclease A.
Raman spectra of ribonuclease A in D2O solution at various pD values have been studied with special attention to the N-deuterated imidazolium ring vibration at 1408 cm-1, the SO4(2-) symmetric stretching vibration at 984 cm-1, the amide I' band, and the tyrosine doublet. Concomitant decrease and increase in the intensities of the 1408- and 984-cm-1 bands in the pD range between 5 and 7 indicate that a sulfate anion is actually hydrogen bonded to an imidazolium ring of a histidine residue located in the interior of the molecule. The mechanism of the sulfate desorption has been compared with that on heat denaturation.
D000818:Animals; D002417:Cattle; D003903:Deuterium; D004722:Endoribonucleases / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles; D010179:Pancreas / Q000201:enzymology; D012259:Ribonuclease, Pancreatic; D013059:Spectrum Analysis, Raman / Q000379:methods; D013431:Sulfates
D007093:Imidazoles; D013431:Sulfates; D003903:Deuterium; D004722:Endoribonucleases; D012259:Ribonuclease, Pancreatic