cDNA Isolation and Functional Characterization of UDP-d-glucuronic Acid 4-Epimerase Family from Ornithogalum caudatum

• Published in: Molecules (Basel, Switzerland) Vol. 21; no. 11; p. 1505
• Main Authors: Yin, Sen, Sun, Yu-Jia, Liu, Ming, Li, Li-Na, Kong, Jian-Qiang
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 09.11.2016; MDPI
• Subjects: ">d-galacturonic acid; ">d-glucuronic acid; ">d-glucuronic acid 4-epimerase; Acids; Biosynthesis; Carbohydrate Epimerases - biosynthesis; Carbohydrate Epimerases - genetics; DNA, Complementary; Flowers & plants; Gene Expression; Genes; Genetic engineering; Ornithogalum; Ornithogalum - enzymology; Ornithogalum - genetics; Ornithogalum caudatum; Pichia; Pichia pastoris; Plant Proteins - biosynthesis; Plant Proteins - genetics; Plant Roots - enzymology; Plant Roots - genetics; Pneumonia; polysaccharides; Recombinant Proteins - biosynthesis; Recombinant Proteins - genetics; Synthetic biology; UDP; Uridine Diphosphate Sugars - genetics; Uridine Diphosphate Sugars - metabolism; UDP; polysaccharides; ">d-glucuronic acid 4-epimerase; Ornithogalum caudatum; ">d-glucuronic acid; ">d-galacturonic acid
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules21111505

d-Galacturonic acid (GalA) is an important component of GalA-containing polysaccharides in . The incorporation of GalA into these polysaccharides from UDP-d-galacturonic acid (UDP-GalA) was reasonably known. However, the cDNAs involved in the biosynthesis of UDP-GalA were still unknown. In the present investigation, one candidate UDP-d-glucuronic acid 4-epimerase (UGlcAE) family with three members was isolated from based on RNA-Seq data. Bioinformatics analyses indicated all of the three isoforms, designated as OcUGlcAE1~3, were members of short-chain dehydrogenases/reductases (SDRs) and shared two conserved motifs. The three full-length cDNAs were then transformed to GS115 for heterologous expression. Data revealed both the supernatant and microsomal fractions from the recombinant expressing can interconvert UDP-GalA and UDP-d-glucuronic acid (UDP-GlcA), while the other two OcUGlcAEs had no activity on UDP-GlcA and UDP-GalA. Furthermore, expression analyses of the three epimerases in varied tissues of were performed by real-time quantitative PCR (RT-qPCR). Results indicated , together with the other two -like genes, was root-specific, displaying highest expression in roots. OcUGlcAE3 was UDP-d-glucuronic acid 4-epimerase and thus deemed to be involved in the biosynthesis of root polysaccharides. Moreover, was proposed to be environmentally induced.