Probing Heme Active Sites of Hemoglobin in Functional Red Blood Cells Using Resonance Raman Spectroscopy

• DOI: 10.1021/acs.jpcb.1c01199
• Publication Date: 2021-03-31T16:25:11Z
• Authors: Jakub Dybas; Tapiwa Chiura; Katarzyna M. Marzec; Piotr J. Mak
• Keywords: Resonance Raman spectroscopy

The UV-vis absorption, Raman imaging, and resonance (rR) spectroscopy methods were employed to study cyanohemoglobin (HbCN) adducts inside living functional red blood cells (RBCs). cyanide ligands are especially optically sensitive probes of the active site environment heme proteins. rR studies HbCN its isotopic analogues (13CN-, C15N-, 13C15N-), as well a careful deconvolution spectral data, revealed that ν(Fe-CN) stretching, δ(Fe-CN) bending, ν(C≡N) stretching modes occur at 454, 382, 2123 cm-1, respectively. Interestingly, while exhibit same frequencies in both isolated RBC-enclosed hemoglobin molecules, small frequency differences observed bending values their shifts. These show even though overall tilted conformation Fe-C≡N fragment is preserved enclosed within cells, there difference degree distortion fragment. slight changes ligand geometry can be reasonably attributed high ordering tight packing Hb molecules RBCs.