Abstract
Genes encoding l-arabinose transporters in Kluyveromyces marxianus and Pichia guilliermondii were identified by functional complementation of Saccharomyces cerevisiae whose growth on l-arabinose was dependent on a functioning l-arabinose transporter, or by screening a differential display library, respectively. These transporters also transport d-xylose and were designated KmAXT1 (arabinose–xylose transporter) and PgAXT1, respectively. Transport assays using l-arabinose showed that KmAxt1p has Km 263 mm and Vmax 57 nm/mg/min, and PgAxt1p has Km 0.13 mm and Vmax 18 nm/mg/min. Glucose, galactose and xylose significantly inhibit l-arabinose transport by both transporters. Transport assays using d-xylose showed that KmAxt1p has Km 27 mm and Vmax 3.8 nm/mg/min, and PgAxt1p has Km 65 mm and Vmax 8.7 nm/mg/min. Neither transporter is capable of recovering growth on glucose or galactose in a S. cerevisiae strain deleted for hexose and galactose transporters. Transport kinetics of S. cerevisiae Gal2p showed Km 371 mm and Vmax 341 nm/mg/min for l-arabinose, and Km 25 mm and Vmax 76 nm/mg/min for galactose. Due to the ability of Gal2p and these two newly characterized transporters to transport both l-arabinose and d-xylose, one scenario for the complete usage of biomass-derived pentose sugars would require only the low-affinity, high-throughput transporter Gal2p and one additional high-affinity general pentose transporter, rather than dedicated d-xylose or l-arabinose transporters. Additionally, alignment of these transporters with other characterized pentose transporters provides potential targets for substrate recognition engineering.
Original language | American English |
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Pages (from-to) | 615-628 |
Number of pages | 14 |
Journal | Yeast |
Volume | 32 |
Issue number | 10 |
DOIs | |
State | Published - 2015 |
Bibliographical note
Publisher Copyright:Copyright © 2015 John Wiley & Sons, Ltd.
NREL Publication Number
- NREL/JA-5100-63256
Keywords
- arabinose
- GAL2
- transport
- xylose
- yeast