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

• Main Authors: Víctor Martínez-Rosas, Merit Valeria Juárez-Cruz, Edson Jiovany Ramírez-Nava, Beatriz Hernández-Ochoa, Laura Morales-Luna, Abigail González-Valdez, Hugo Serrano-Posada, Noemí Cárdenas-Rodríguez, Paulina Ortiz-Ramírez, Sara Centeno-Leija, Roberto Arreguin-Espinosa, Miguel Cuevas-Cruz, Daniel Ortega-Cuellar, Verónica Pérez de la Cruz, Luz María Rocha-Ramírez, Edgar Sierra-Palacios, Rosa Angélica Castillo-Rodríguez, Isabel Baeza-Ramírez, Jaime Marcial-Quino, Saúl Gómez-Manzo
• Format: Article
• Language: English
• Published: MDPI AG 2020-04-01
• Series: International Journal of Molecular Sciences
• Subjects: human G6PD mutants; G6PD deficiency; protein stability; structural characterization; catalytic activity
• Online Access: https://www.mdpi.com/1422-0067/21/8/2732
• ISSN: 1661-6596; 1422-0067

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.