Abstract
NADPH-dependent 5-keto-D-gluconate reductase was identified as a missing element in the pathway for D-glucuronate catabolism in fungi. The disruption of the gene, gluF, by CRISPR/Cas9 in the filamentous fungus Aspergillus niger resulted in a strain unable to catabolise D-glucuronate. The purified GluF protein was characterized and kcat and Km values of 23.7 ± 1.8 s-1 and 3.2 ± 0.1 mm for 5-keto-D-gluconate, respectively, were determined. The enzyme is reversible and is active with NADP+ and D-gluconate. We suggest a pathway for D-glucuronate catabolism with the intermediates L-gulonate, 2-keto-L-gulonate, L-idonate, 5-keto-D-gluconate, D-gluconate and D-gluconate-6-phosphate which is a part of the pentose phosphate pathway. A fungal enzyme activity for the conversion of L-gulonate to 2-keto-L-gulonate remains to be identified.
Original language | English |
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Pages (from-to) | 71-77 |
Journal | FEBS Letters |
Volume | 592 |
Issue number | 1 |
DOIs | |
Publication status | Published - 1 Jan 2018 |
MoE publication type | A1 Journal article-refereed |
Funding
This work was supported by the Academy of Finland through the New Energy Programme (grant 311958).
Keywords
- 5-keto-gluconate
- Aspergillus niger
- CRISPR/Cas9
- D-gluconate-5-dehydrogenase
- D-glucuronate
- EC 1.1.1.69
- Fungal pathway