The cobalt-nitrosyl stretching vibration as a sensitive resonance Raman probe for distal histidine-nitrosyl interaction in monomeric hemoglobins.
The Co-NO stretching vibration has been assigned in the resonance Raman spectra of various cobalt-substituted monomeric hemoglobins by employing isotope-labeling of nitrosyl (14N16O, 15N16O, 14N18O). Monomeric hemoglobins with a distal histidine (sperm whale myoglobin and leghemoglobin) exhibit this vibration at 573-575 cm-1, whereas hemoglobins without distal histidine (elephant myoglobin and insect hemoglobin from Chironomus thummi thummi, CTT III) show this vibration in the range of 553-558 cm-1. The Fe-NO stretching vibration which occurs in the range of 554-556 cm-1 does not reflect the distal histidine-ligand interaction. Therefore, the Co-NO moiety which is isoelectronic with the Fe-O2 moiety is a good monitor for distal effects on the exogenous ligand of hemoglobins, especially due to the fact that in hemoglobins with distal histidine the Fe-O2 stretching vibration (567-572 cm-1) is similar to the Co-NO stretching vibration.
D000818:Animals; D002683:Chironomidae; D003035:Cobalt; D004606:Elephants; D006454:Hemoglobins / Q000032:analysis*; D006639:Histidine / Q000032:analysis; D007874:Leghemoglobin / Q000032:analysis; D009211:Myoglobin / Q000032:analysis; D011485:Protein Binding; D013025:Glycine max; D013059:Spectrum Analysis, Raman; D014907:Whales
D006454:Hemoglobins; D007874:Leghemoglobin; D009211:Myoglobin; C008657:nitrosyl hemoglobin; D003035:Cobalt; D006639:Histidine