A single membrane-bound enzyme catalyzes the conversion of 2,5-diketo-d-gluconate to 4-keto-d-arabonate in d-glucose oxidative fermentation by Gluconobacter oxydans NBRC 3292

作者：Tazoe Masaaki^*; Oishi Hiromi; Kobayashi Setsuko; Hoshino Tatsuo

来源：Bioscience Biotechnology and Biochemistry, 2016, 80(8): 1505-1512.

DOI：10.1080/09168451.2016.1164584

• membrane-bound 4-keto-D-arabonate synthase
• 2,5-diketo-D-gluconate
• Glu-conobacter oxydans
• D-tartaric acid

4-Keto-d-arabonate synthase (4KAS), which converts 2,5-diketo-d-gluconate (DKGA) to 4-keto-d-arabonate (4KA) in d-glucose oxidative fermentation by some acetic acid bacteria, was solubilized from the Gluconobacter oxydans NBRC 3292 cytoplasmic membrane, and purified in an electrophoretically homogenous state. A single membrane-bound enzyme was found to catalyze the conversion from DKGA to 4KA. The 92-kDa 4KAS was a homodimeric protein not requiring O-2 or a cofactor for the conversion, but was stimulated by Mn2+. N-terminal amino acid sequencing of 4KAS, followed by gene homology search indicated a 1,197-bp open reading frame (ORF), corresponding to the GLS_c04240 locus, GenBank accession No. CP004373, encoding a 398-amino acid protein with a calculated molecular weight of 42,818Da. An Escherichia coli transformant with the 4kas plasmid exhibited 4KAS activity. Furthermore, overexpressed recombinant 4KAS was purified in an electrophoretically homogenous state and had the same molecular size as the natural enzyme.

• 出版日期2016-8