Institute of Biology II, Molecular Biology of Archaea, University of Freiburg, Freiburg, Germany.
Molecular Enzyme Technology and Biochemistry (MEB), Biofilm Centre, Centre for Water and Environmental Research (CWE), University of Duisburg-Essen, Essen, Germany.
Appl Environ Microbiol. 2018 Jan 17;84(3). doi: 10.1128/AEM.01273-17. Print 2018 Feb 1.
spp. possess a great metabolic versatility and grow heterotrophically on various carbon sources, such as different sugars and peptides. Known sugar transporters in predominantly belong to ABC transport systems. Although several ABC transporters for sugar uptake have been characterized in the crenarchaeon , only one homologue of these transporters, the maltose/maltooligomer transporter, could be identified in the closely related Comparison of the transcriptome of MW001 grown on peptides alone and peptides in the presence of d-xylose allowed for the identification of the ABC transporter for d-xylose and l-arabinose transport and the gaining of deeper insights into pentose catabolism under the respective growth conditions. The d-xylose/l-arabinose substrate binding protein (SBP) (Saci_2122) of the ABC transporter is unique in and shares more similarity to bacterial SBPs of the carbohydrate uptake transporter-2 (CUT2) family than to any characterized archaeal one. The identified pentose transporter is the first CUT2 family ABC transporter analyzed in the domain of Single-gene deletion mutants of the ABC transporter subunits exemplified the importance of the transport system for d-xylose and l-arabinose uptake. Next to the transporter operon, enzymes of the aldolase-independent pentose catabolism branch were found to be upregulated in N-Z-Amine and d-xylose medium. The α-ketoglutarate semialdehyde dehydrogenase (KGSADH; Saci_1938) seemed not to be essential for growth on pentoses. However, the deletion mutant of the 2-keto-3-deoxyarabinoate/xylonate dehydratase (KDXD [also known as KDAD]; Saci_1939) was no longer able to catabolize d-xylose or l-arabinose, suggesting the absence of the aldolase-dependent branch in Thermoacidophilic microorganisms are emerging model organisms for biotechnological applications, as their optimal growth conditions resemble conditions used in certain biotechnologies such as industrial plant waste degradation. Because of its high genome stability, is especially suited as a platform organism for such applications. For use in (ligno)cellulose degradation, it was important to understand pentose uptake and metabolism in This study revealed that only the aldolase-independent Weimberg pathway is required for growth of MW001 on d-xylose and l-arabinose. Moreover, employs a CUT2 ABC transporter for pentose uptake, which is more similar to bacterial than to archaeal ABC transporters. The identification of pentose-inducible promoters will expedite the metabolic engineering of for its development into a platform organism for (ligno)cellulose degradation.
种属拥有很强的代谢多样性，可以异养生长在各种碳源上，如不同的糖和肽。主要属于 ABC 转运系统。虽然在古菌中已经鉴定出几种糖转运蛋白，但在密切相关的中，仅鉴定出这些转运蛋白的一个同源物，即麦芽糖/麦芽寡聚物转运蛋白。比较单独使用肽和在存在 d-木糖的情况下生长的 MW001 的转录组，鉴定了 d-木糖和 l-阿拉伯糖转运的 ABC 转运蛋白，并深入了解了各自生长条件下戊糖分解代谢。ABC 转运蛋白的 d-木糖/l-阿拉伯糖底物结合蛋白（SBP）（Saci_2122）在中是独特的，与碳水化合物摄取转运蛋白-2（CUT2）家族的细菌 SBP 比任何已鉴定的古菌 SBP 具有更多的相似性。鉴定出的戊糖转运蛋白是在域中分析的第一个 CUT2 家族 ABC 转运蛋白。ABC 转运蛋白亚基的单基因突变体的缺失突变体证明了该转运系统对 d-木糖和 l-阿拉伯糖摄取的重要性。除了转运基因簇外，还发现非醛缩酶戊糖分解代谢分支的酶在 N-Z-Amine 和 d-木糖培养基中上调。α-酮戊二酸半醛脱氢酶（KGSADH；Saci_1938）似乎不是戊糖生长所必需的。然而，2-酮-3-脱氧阿拉伯酸/木酮酸盐脱水酶（KDXD[也称为 KDAD]；Saci_1939）的缺失突变体不再能够分解 d-木糖或 l-阿拉伯糖，表明中不存在依赖醛缩酶的分支。嗜热微生物作为生物技术应用的新兴模式生物，因为它们的最佳生长条件类似于某些生物技术（如工业植物废物降解）中使用的条件。由于其基因组高度稳定，因此特别适合作为此类应用的平台生物。为了在（木质）纤维素降解中使用，了解中戊糖的吸收和代谢非常重要。本研究表明，只有非醛缩酶依赖的 Weimberg 途径是 MW001 在 d-木糖和 l-阿拉伯糖上生长所必需的。此外，MW001 使用 CUT2 ABC 转运蛋白吸收戊糖，该转运蛋白与细菌 ABC 转运蛋白更相似，而与古菌 ABC 转运蛋白更相似。鉴定戊糖诱导启动子将加速 MW001 的代谢工程，将其开发为（木质）纤维素降解的平台生物。
