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Updated: Jun 7, 2026

Characterization of Sickling During Controlled Automated Deoxygenation with Oxygen Gradient Ektacytometry
08:23

Characterization of Sickling During Controlled Automated Deoxygenation with Oxygen Gradient Ektacytometry

Published on: November 5, 2019

Comparative in silico analysis of hemoglobin subunits HBB, HbS (p.Glu7Val), and HBA: Sequence-structure insights into

Maryam Dhary Kamel1, Rejwan Khaleel Ibrahim2, Wael Rasheed Obaead3

  • 1Department of Biotechnology, College of Applied Science, University of Technology, Baghdad, Iraq.

Computational Biology and Chemistry
|June 5, 2026
PubMed

Sickle cell anemia is caused by a single missense mutation in the human beta globin gene (HBB) that replaced glutamic acid with valine at position 7(p.Glu7Val), producing sickle hemoglobin (HbS) and promoting polymer formation under deoxygenated conditions. In the present in silico study, genomic and protein sequences of HBB (normal beta globin), HbS variant beta globin (HbS) and hemoglobin alpha globin (HBA) were retrieved from NCBI in FASTA format and analyzed comparatively. physicochemical properties were computed using ExPASY protparam, secondary structure features were predicted using PSIPRED, and three-dimensional /quaternary structural modeling was performed using SWISS-MODEL with template selection from PDB. The ProtParam analysis display that the p.Glu7Val substitution in HBBs reduced the number of acidic residues (Asp+Glu) and shifted the theoretical PI upward(HBB:6.740, HBBs:7.131) accompanied by a∼30 Da decrease in molecular weight and a modest increase in hydrophobicity related indices (aliphatic index and GRAVY). PSIPRED predicted predominantly alpha helical globin folds for all subunits, with only minor differences between HBB and HbS. Structural inspection of the SWISS-MODEL assemblies localized Val 7 at the Beta chain N-terminus and consistent with the classical mechanism whereby this hydrophobic substitution creates a surface stick region that can engage hydrophobic patches on neighboring deoxy Hb molecules, providing structural context consistent with HbS polymerization and downstream erythrocyte sickling. Overall, this computational workflow provides a clear sequence to structure interpretation of the HbS mutation and highlights measurable physicochemical shifts associated with SCA.

Keywords:
HbSPSIPRED and SWISS-MODELProtparam serverSickle cell anemia

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