Novel transporters from Kluyveromyces marxianus and Pichia guilliermondii expressed in Saccharomyces cerevisiae enable growth on l‐arabinose and d‐xylose. Issue 10 (17th August 2015)

• Record Type: Journal Article
• Authors: Knoshaug, Eric P.; Vidgren, Virve; Magalhães, Frederico; Jarvis, Eric E.; Franden, Mary Ann; Zhang, Min; Singh, Arjun
• Is Part Of: Yeast. Volume 32:Issue 10(2015:Oct.)
• Page Start: 615
• Page End: 628
• Publication Date: 2015-08-17
• Subjects: Yeast -- Periodicals; Yeasts -- Periodicals; Yeasts -- genetics -- Periodicals; Electronic journals; 547
• DOI: 10.1002/yea.3084
• Languages: English
• ISSNs: 0749-503X

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>Genes encoding <sc>l</sc>‐arabinose transporters in <italic>Kluyveromyces marxianus</italic> and <italic>Pichia guilliermondii</italic> were identified by functional complementation of <italic>Saccharomyces cerevisiae</italic> whose growth on <sc>l</sc>‐arabinose was dependent on a functioning <sc>l</sc>‐arabinose transporter, or by screening a differential display library, respectively. These transporters also transport <sc>d</sc>‐xylose and were designated <italic>KmAXT1</italic> (arabinose–xylose transporter) and <italic>PgAXT1</italic>, respectively. Transport assays using <sc>l</sc>‐arabinose showed that KmAxt1p has <italic>K</italic><sub>m</sub> 263 m<sc>m</sc> and <italic>V</italic><sub>max</sub> 57 n<sc>m</sc>/mg/min, and PgAxt1p has <italic>K</italic><sub>m</sub> 0.13 m<sc>m</sc> and <italic>V</italic><sub>max</sub> 18 n<sc>m</sc>/mg/min. Glucose, galactose and xylose significantly inhibit <sc>l</sc>‐arabinose transport by both transporters. Transport assays using <sc>d</sc>‐xylose showed that KmAxt1p has <italic>K</italic><sub>m</sub> 27 m<sc>m</sc> and <italic>V</italic><sub>max</sub> 3.8 n<sc>m</sc>/mg/min, and PgAxt1p has <italic>K</italic><sub>m</sub> 65 m<sc>m</sc> and <italic>V</italic><sub>max</sub> 8.7 n<sc>m</sc>/mg/min. Neither transporter is capable of recovering growth on glucose or galactose in a <italic>S. cerevisiae</italic> strain deleted for hexose and galactose transporters. Transport kinetics of <italic>S. cerevisiae</italic> Gal2p showed <italic>K</italic><sub>m</sub> 371 m<sc>m</sc> and <italic>V</italic><sub>max</sub> 341 n<sc>m</sc>/mg/min for <sc>l</sc>‐arabinose, and <italic>K</italic><sub>m</sub> 25 m<sc>m</sc> and <italic>V</italic><sub>max</sub> 76 n<sc>m</sc>/mg/min for galactose. Due to the ability of Gal2p and these two newly characterized transporters to transport both <sc>l</sc>‐arabinose and <sc>d</sc>‐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 <sc>d</sc>‐xylose or <sc>l</sc>‐arabinose transporters. Additionally, alignment of these transporters with other characterized pentose transporters provides potential targets for substrate recognition engineering. Accession Nos: <italic>KmAXT1</italic>: GZ791039; <italic>PgAXT1</italic>: GZ791040 Copyright © 2015 John Wiley & Sons, Ltd.</p> </abstract>