eng Oriental Scientific Publishing Company Biomedical and Pharmacology Journal 0974-6242 2024-12-30 17 4 2445 2454 10.13005/bpj/3037 63105 article Seruni Kusuma Udyaningsih Freisleben 1 Hans-Joachim Freisleben 2 Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Campus Depok, Depok, Indonesia Medical Research Unit, Faculty of Medicine, Universitas Indonesia, Campus Salemba, Salemba Raya, Jakarta, Indonesia Thalassemic hemoglobin (Hb) differs from normal Hb in its structure and oxygen-binding capacity. To find out structural differences in their heme-iron sites, X-ray absorption fine structure (XAFS) was applied. Resulting data in the range of 0 ≤ k ≤1 6 Å^-1 and 1 ≤ k ≤ 14 Å^-1 obtained from frozen aqueous solutions (10 K) of normal and thalassemic HbE/F deoxy forms were refined using multiple-scattering (MS) analyses. To test the robustness of the refinements R starting models, constraints, restraints, and k ranges were varied; for normal relaxed R- and tense T-deoxy-Hb final XAFS R values were 13% and 17% and for thalassemic HbE/F relaxed R-deoxy-Hb R value was 19-21%. With normal R-deoxy-Hb, we obtained Fe-N_p (pyrrole) and Fe-N_€(imidazole) distances of 2.05 Å and 2.14 Å, whereas in thalassemic HbE/F R-deoxy-Hb, these values were 2.11Å  and 1.9Å , respectively. In the T-state of normal deoxy-Hb, Fe-N_p distance (2.08 Å)  was longer and Fe-N_€ (1.96 Å) shorter than in the R-state; from thalassemic HbE/F T-deoxy-Hb we could not obtain sufficiently stable probes for XAFS measurement. In normal and HbE/F R-deoxy-Hb the Fe-His imidazole bond deviated from the z-axis by ~10⁰, whereas it was on the z-axis in the T-state of normal Hb. Heme doming increased from normal R-deoxy via normal T-deoxy to thalassemic R-deoxy forms with simultaneously increasing dislocation of the central iron from the plane of the porphyrin. Oxygenation brings the iron back into the plane of the porphyrin ring. https://biomedpharmajournal.org/vol17no4/x-ray-analysis-of-fine-structure-of-heme-in-normal-and-thalassemic-hbe-f-hemoglobin/ Beta-thalassemia Heme fine Structure Hemoglobin Synchrotron Thalassemic HbE/F X-ray absorption fine structure (XAFS)