Abstract
Glucose-6-phosphate dehydrogenase (G6PD) deficiency in humans causes severe disease, varying from mostly asymptomatic individuals to patients showing neonatal jaundice, acute hemolysis episodes or chronic nonspherocytic hemolytic anemia. In order to understand the effect of the mutations in G6PD gene function and its relation with G6PD deficiency severity, we report the construction, cloning and expression as well as the detailed kinetic and stability characterization of three purified clinical variants of G6PD that present in the Mexican population: G6PD Zacatecas (Class I), Vanua-Lava (Class II) and Viangchan (Class II). For all the G6PD mutants, we obtained low purification yield and altered kinetic parameters compared with Wild Type (WT). Our results show that the mutations, regardless of the distance from the active site where they are located, affect the catalytic properties and structural parameters and that these changes could be associated with the clinical presentation of the deficiency. Specifically, the structural characterization of the G6PD Zacatecas mutant suggests that the R257L mutation have a strong effect on the global stability of G6PD favoring an unstable active site. Using computational analysis, we offer a molecular explanation of the effects of these mutations on the active site.
Highlights
Glucose-6-phosphate dehydrogenase (G6PD) (EC 1.1.1.49) is a cytosolic enzyme [1] involved in the first step of the pentose phosphate pathway, which catalyzes the conversion of β-D-glucose-6phosphate into D-glucono-1,5-lactone-6-phosphate with the concomitant production of one molecule of nicotinamide adenine dinucleotide phosphate (NADPH) (Figure 1A)
The biochemical results obtained in this study of the three recombinant G6PD mutants, Zacatecas (R257L), Vanua-Lava (L128P), and Viangchan (V291M), showed a low purification yield of G6PD mutants and are effect in their kinetic parameters, where the G6PD Zacatecas was the most affected mutant showing three- and four-fold lower affinity for both physiological substrates compared with the Wild Type (WT) G6PD enzyme
The structural characterization suggests that the mutations in the WT G6PD have a strong effect on the global stability of G6PD
Summary
Glucose-6-phosphate dehydrogenase (G6PD) (EC 1.1.1.49) is a cytosolic enzyme [1] involved in the first step of the pentose phosphate pathway, which catalyzes the conversion of β-D-glucose-6phosphate into D-glucono-1,5-lactone-6-phosphate with the concomitant production of one molecule of nicotinamide adenine dinucleotide phosphate (NADPH) (Figure 1A). The G6PD deficiency causes severe disease ranging from mostly asymptomatic individuals to patients showing neonatal jaundice, acute episodes of hemolysis triggered by exogenous agents (acute infections, drugs or food), and chronic nonspherocytic hemolytic anemia [5]. This disease has genetic heterogeneity with around 186 mutations reported up to date, mainly point mutations that lead to single amino acid substitutions [6,7,8]. Only around 10% of all recognized G6PD mutants have been characterized at the structural and functional level. From these 186 G6PD mutations, in Mexico the existence of 19 different mutants, including the mutants G6PD Zacatecas, Vanua-Lava and Viangchan, has been reported [9,10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
