Characterization of L-arabinose/D-galactose 1-dehydrogenase from Thermotoga maritima and its application in galactonate production

  • World J Microbiol Biotechnol. 2022 Sep 16;38(12):223. doi: 10.1007/s11274-022-03406-1.
Mengke Xue  1 ,  Sizhong Feng  1 ,  Fang Xie  1 ,  Hongyang Zhao  1 ,  Yemin Xue  2
Affiliations
  • 1. School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Xuelin Road 2, Xianlin Street, Qixia District, Nanjing, Jiangsu, 210023, People's Republic of China.
  • 2. School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Xuelin Road 2, Xianlin Street, Qixia District, Nanjing, Jiangsu, 210023, People's Republic of China. [email protected].
PMID: 36109417 DOI: 10.1007/s11274-022-03406-1
Abstract

The first hyperthermophilic L-arabinose/D-galactose 1-dehydrogenase (TmAraDH) from Thermotoga maritima was heterologously purified from Escherichia coli. It belongs to the Gfo/Idh/MocA protein family, prefers NAD+/NADP+ as a cofactor. The purified TmAraDH exhibited maximum activity toward L-arabinose at 75 °C and pH 8.0, and retained 63.7% of its activity after 24 h at 60 °C, and over 60% of its activity after holding a pH ranging from 7.0 to 9.0 for 1 h. Among all tested substrates, TmAraDH exclusively catalyzed the NAD(P)+-dependent oxidation of L-arabinose, D-galactose and D-fucose. The catalytic efficiency (kcat/Km) towards L-arabinose and D-galactose was 123.85, 179.26 min-1 mM-1 for NAD+, and 56.06, 18.19 min-1 mM-1 for NADP+, respectively. TmAraDH exhibited complete oxidative conversion in 12 h at 70 °C to D-galactonate with 5 mM D-galactose. Modelling provides structural insights into the cofactor and substrate recognition specificity. Our results suggest that TmAraDH have great potential for the conversion of L-arabinose and D-galactose to L-arabonate and D-galactonate.

Keywords
D-galactonate; D-galactose; L-arabinose/D-galactose 1-dehydrogenase; Thermotoga maritima.
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