An inherent genetic enzyme disorder in humans, known as glucose-6-phosphate dehydrogenase (G6PD) deficiency, arises due to specific mutations. While the prevailing approach for investigating G6PD variants involves biochemical analysis, the intricate structural details remain limited, impeding a comprehensive understanding of how different G6PD variants of varying classes impact their functionality. This study 22 examined the dynamic properties of G6PD wild types and six G6PD variants from 23 different classes using molecular dynamic simulation (MDS). The wild-type and variant 24 G6PD structures unveil high fluctuations within the amino acid range of 274-515, the structural NADP+ binding site, pivotal for enzyme dimerization. Specifically, two variants, G6PDZacatecas (R257L) and G6PDDurham (K238R), demonstrate compromised structural stability at the dimer interface, attributable to the disruption of a salt bridge involving Glu 206 and Lys 407, along with the disturbance of hydrogen bonds formed by Asp 421 at the βN-βN sheets. Consequently, this impairment cascades to affect the binding affinity of crucial interactions, such as Lys 171-Glucose-6-Phosphate (G6P) and Lys 171-catalytic NADP+, leading to diminished enzyme activity. This study underscores the utility of computational in silico techniques in predicting the structural alterations and flexibility of G6PD variants. This insight holds promise for guiding future endeavors in drug development targeted at mitigating the impacts of G6PD deficiency.
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzyme defect that affects more than 500 million people worldwide. Individuals affected with G6PD deficiency may occasionally suffer mild-to-severe chronic hemolytic anemia. Chronic non-spherocytic hemolytic anemia (CNSHA) is a potential result of the Class I G6PD variants. This comparative computational study attempted to correct the defect in variants structure by docking the AG1 molecule to selected Class I G6PD variants [G6PDNashville (Arg393His), G6PDAlhambra (Val394Leu), and G6PDDurham (Lys238Arg)] at the dimer interface and structural NADP+ binding site. It was followed by an analysis of the enzyme conformations before and after binding to the AG1 molecule using the molecular dynamics simulation (MDS) approach, while the severity of CNSHA was determined via root-mean-square deviation (RMSD), root-mean-square fluctuation (RMSF), hydrogen bonds, salt bridges, radius of gyration (Rg), solvent accessible surface area analysis (SASA), and principal component analysis (PCA). The results revealed that G6PDNashville (Arg393His) and G6PDDurham (Lys238Arg) had lost the direct contact with structural NADP+ and salt bridges at Glu419 - Arg427 and Glu206 - Lys407 were disrupted in all selected variants. Furthermore, the AG1 molecule re-stabilized the enzyme structure by restoring the missing interactions. Bioinformatics approaches were also used to conduct a detailed structural analysis of the G6PD enzyme at a molecular level to understand the implications of these variants toward enzyme function. Our findings suggest that despite the lack of treatment for G6PDD to date, AG1 remains a novel molecule that promotes activation in a variety of G6PD variants.