Abstract
Human glucose 6-phosphate dehydrogenase (G6PD) has both the “catalytic” NADP + site and a “structural” NADP + site where a number of severe G6PD deficiency mutations are located. Two pairs of G6PD clinical mutants, G6PD Wisconsin (R393G) and G6PD Nashville (R393H), and G6PD Fukaya (G488S) and G6PD Campinas (G488V), in which the mutations are in the vicinity of the “structural” NADP + site, showed elevated K d values of the “structural” NADP +, ranging from 53 nM to 500 nM compared with 37 nM for the wild-type enzyme. These recombinant enzymes were denatured by Gdn-HCl and refolded by rapid dilution in the presence of l-Arg, NADP + and DTT at 25 °C. The refolding yields of the mutants exhibited strong NADP +-dependence and ranged from 1.5% to 59.4% with 1000 μM NADP +, in all cases lower than the figure of 72% for the wild-type enzyme. These mutant enzymes also displayed decreased thermostability and high susceptibility to chymotrypsin digestion, in good agreement with their corresponding melting temperatures in CD experiments. Taken together, the results support the view that impaired binding of “structural” NADP + can hinder folding as well as cause instability of these clinical mutant enzymes in the fully folded state.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease
Disclaimer: 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.