A novel L-isoleucine metabolism in Bacillus thuringiensis generating (2S,3R,4S)-4-hydroxyisoleucine, a potential insulinotropic and anti-obesity amino acid.
4-Hydroxyisoleucine (HIL) found in fenugreek seeds has insulinotropic and anti-obesity effects and is expected to be a novel orally active drug for insulin-independent diabetes. Here, we show that the newly isolated strain Bacillus thuringiensis 2e2 and the closely related strain B. thuringiensis ATCC 35646 operate a novel metabolic pathway for L-isoleucine (L-Ile) via HIL and 2-amino-3-methyl-4-ketopentanoic acid (AMKP). The HIL synthesis was catalyzed stereoselectively by an α-ketoglutaric acid-dependent dioxygenase and to be useful for efficient production of a naturally occurring HIL isomer, (2S,3R,4S)-HIL. The (2S,3R,4S)-HIL was oxidized to (2S,3R)-AMKP by a NAD(+)-dependent dehydrogenase. The metabolic pathway functions as an effective bypass pathway that compensates for the incomplete tricarboxylic acid (TCA) cycle in Bacillus species and also explains how AMKP, a vitamin B(12) antimetabolite with antibiotic activity, is synthesized. These novel findings pave a new way for the commercial production of HIL and also for AMKP.
Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan. ogawa@kais.kyoto-u.ac.jp
Jun
J
Ogawa
Tomohiro
T
Kodera
Sergey V
SV
Smirnov
Makoto
M
Hibi
Natalia N
NN
Samsonova
Ryoukichi
R
Koyama
Hiroyuki
H
Yamanaka
Junichi
J
Mano
Takashi
T
Kawashima
Kenzo
K
Yokozeki
Sakayu
S
Shimizu
D001413:Bacillus thuringiensis / Q000235:genetics / Q000378:metabolism*; D053898:Biosynthetic Pathways / Q000235:genetics*; D003067:Coenzymes / Q000378:metabolism; D049308:Dioxygenases / Q000235:genetics / Q000378:metabolism; D007532:Isoleucine / Q000031:analogs & derivatives* / Q000096:biosynthesis*; D007651:Keto Acids / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism; D010421:Pentanoic Acids / Q000378:metabolism
C104672:4-hydroxyisoleucine; C531471:4-oxopentanoic acid; D003067:Coenzymes; D007651:Keto Acids; D010421:Pentanoic Acids; D007532:Isoleucine; D009243:NAD; D010088:Oxidoreductases; D049308:Dioxygenases