Structure analysis of bovine lens calf gamma-II crystallin: residue assignments of the five histidine CE1 resonances observed by proton-nuclear magnetic resonance spectroscopy.
Bovine lens calf gamma-II crystallin contains five histidine residues at sequence positions 14, 53, 84, 117, and 122. The protein was examined by proton nuclear magnetic resonance spectroscopy at 300 MHz. Five histidine epsilon-1 carbon (CE1) proton resonances were observed titrating with pH between 8.9 and 7.4 ppm. The chemical shift values as a function of pH were fitted to a Henderson-Hasselbalch equation. The experimental pK values and end points of titration were then compared to theoretical electrostatic and ring-current calculations based on the 1.6 A resolution x-ray coordinate data of the protein. A sufficiently close correspondence between the experimental and calculated values allowed histidine residue assignments to be made.
Garner
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Discovery Research, Allergan, Inc., Irvine, CA 92715.
Balaji
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D000818:Animals; D002417:Cattle; D055598:Chemical Phenomena; D002621:Chemistry; D003459:Crystallins; D006639:Histidine; D009682:Magnetic Resonance Spectroscopy; D008433:Mathematics; D013223:Statistics as Topic
D003459:Crystallins; D006639:Histidine