Structural and kinetic differences between human and Aspergillus fumigatus D-glucosamine-6-phosphate N-acetyltransferase.

Abstract

Aspergillus fumigatus is the causative agent of aspergillosis, a frequently invasive colonization of the lungs of immunocompromised patients. GNA1 (D-glucosamine-6-phosphate N-acetyltransferase) catalyses the acetylation of GlcN-6P (glucosamine-6-phosphate) to GlcNAc-6P (N-acetylglucosamine-6-phosphate), a key intermediate in the UDP-GlcNAc biosynthetic pathway. Gene disruption of gna1 in yeast and Candida albicans has provided genetic validation of the enzyme as a potential target. An understanding of potential active site differences between the human and A. fumigatus enzymes is required to enable further work aimed at identifying selective inhibitors for the fungal enzyme. In the present study, we describe crystal structures of both human and A. fumigatus GNA1, as well as their kinetic characterization. The structures show significant differences in the sugar-binding site with, in particular, several non-conservative substitutions near the phosphate-binding pocket. Mutagenesis targeting these differences revealed drastic effects on steady-state kinetics, suggesting that the differences could be exploitable with small-molecule inhibitors.

DOI: 10.1042/BJ20081000

Extracted Key Phrases

6 Figures and Tables

Cite this paper

@article{HurtadoGuerrero2008StructuralAK, title={Structural and kinetic differences between human and Aspergillus fumigatus D-glucosamine-6-phosphate N-acetyltransferase.}, author={Ram{\'o}n Hurtado-Guerrero and Olawale G Raimi and Jinrong Min and Hong Zeng and Laura Vallius and Sharon M. Shepherd and Adel F. M. Ibrahim and Hong Wu and Alexander N. Plotnikov and Daan M F van Aalten}, journal={The Biochemical journal}, year={2008}, volume={415 2}, pages={217-23} }