Laboratorio de Bioquímica Genética, Instituto Nacional de Pediatría, Secretaría de Salud, Mexico City 04530, Mexico.
Laboratorio de Nutrición Experimental, Instituto Nacional de Pediatría, Secretaría de Salud, Mexico City 04530, Mexico.
Int J Mol Sci. 2017 Oct 26;18(11):2244. doi: 10.3390/ijms18112244.
Glucose-6-phosphate dehydrogenase (G6PD) is a key regulatory enzyme that plays a crucial role in the regulation of cellular energy and redox balance. Mutations in the gene encoding G6PD cause the most common enzymopathy that drives hereditary nonspherocytic hemolytic anemia. To gain insights into the effects of mutations in G6PD enzyme efficiency, we have investigated the biochemical, kinetic, and structural changes of three clinical G6PD variants, the single mutations G6PD A+ (Asn126AspD) and G6PD Nefza (Leu323Pro), and the double mutant G6PD A- (Asn126Asp + Leu323Pro). The mutants showed lower residual activity (≤50% of WT G6PD) and displayed important kinetic changes. Although all Class III mutants were located in different regions of the three-dimensional structure of the enzyme and were not close to the active site, these mutants had a deleterious effect over catalytic activity and structural stability. The results indicated that the G6PD Nefza mutation was mainly responsible for the functional and structural alterations observed in the double mutant G6PD A-. Moreover, our study suggests that the G6PD Nefza and G6PD A- mutations affect enzyme functions in a similar fashion to those reported for Class I mutations.
葡萄糖-6-磷酸脱氢酶（G6PD）是一种关键的调节酶，在细胞能量和氧化还原平衡的调节中起着至关重要的作用。编码 G6PD 的基因突变导致最常见的酶病，即遗传性非球形细胞溶血性贫血。为了深入了解 G6PD 酶效率突变的影响，我们研究了三种临床 G6PD 变体的生化、动力学和结构变化，这三种变体分别是单突变 G6PD A+（Asn126AspD）和 G6PD Nefza（Leu323Pro），以及双突变 G6PD A-（Asn126Asp + Leu323Pro）。这些突变体表现出较低的剩余活性（≤WT G6PD 的 50%），并且显示出重要的动力学变化。尽管所有的 Class III 突变体都位于酶的三维结构的不同区域，且不接近活性位点，但这些突变体对催化活性和结构稳定性有有害影响。结果表明，G6PD Nefza 突变主要负责观察到的双突变 G6PD A-的功能和结构改变。此外，我们的研究表明，G6PD Nefza 和 G6PD A-突变以与报道的 Class I 突变相似的方式影响酶的功能。
