Effects of Single and Double Mutants in Human Glucose-6-Phosphate Dehydrogenase Variants Present in the Mexican Population: Biochemical and Structural Analysis

Abstract

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most frequent human enzymopathy, affecting over 400 million people globally. Worldwide, 217 mutations have been reported at the genetic level, and only 19 have been found in Mexico. The objective of this work was to contribute to the knowledge of the function and structure of three single natural variants (G6PD A+, G6PD San Luis Potosi, and G6PD Guadalajara) and a double mutant (G6PD Mount Sinai), each localized in a different region of the three-dimensional (3D) structure. In the functional characterization of the mutants, we observed a decrease in specific activity, protein expression and purification, catalytic efficiency, and substrate affinity in comparison with wild-type (WT) G6PD. Moreover, the analysis of the effect of all mutations on the structural stability showed that its presence increases denaturation and lability with temperature and it is more sensible to trypsin digestion protease and guanidine hydrochloride compared with WT G6PD. This could be explained by accelerated degradation of the variant enzymes due to reduced stability of the protein, as is shown in patients with G6PD deficiency.

Molecular dynamics of G6PD variants from sub-Saharan Africa

“…This increase in motion may lead to increased molecular stresses which overall reduce stability. This is supported by previous work showing ABEN having a cooperative impact on the reduction of enzyme stability when in combination with ADEL, and other G6PD variants [28] , [29] . These molecular interpretations correlate with clinical evidence that showed the ABEN variant to be a genetic modifier of the impact induced by ADEL on enzyme activity and risk of G6PD deficiency [30] .…”

Hematological and molecular analysis of patients with G6PD deficiency revealed coexistent hereditary spherocytosis and alpha thalassemia

“…G6PD A +376G , typically classified as an asymptomatic class IV G6PD deficiency variant (Luzzatto et al, 2020), was recently considered a class III variant. According to in vitro findings by Gómez-Manzo et al (2015), it produces a thermolabile mutated protein with 50% catalytic efficiency due to the alteration of its functional and structural stability (Gómez-Manzo et al, 2015;Martínez-Rosas et al, 2020). This suggests that this variant may have been involved in producing positive G6PD test results for the patients in this study; however, additional mutations in the G6PD gene remain to be identified.…”

Kinetic and Molecular Docking Studies to Determine the Effect of Inhibitors on the Activity and Structure of Fused G6PD::6PGL Protein from Trichomonas vaginalis

“…Glucose-6-phosphate-dehydrogenase (G6PD) is a housekeeping cytosolic enzyme in all life forms, from prokaryotes to animals. It catalyzes the first rate-limiting step of the oxidative phase in the PPP [13,14]. The T. vaginalis g6pd gene is fused with the gene that codes for 6-phosphogluconolactonase (GPGL), giving rise to a fused G6PD::6PGL protein.…”