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Elucidation of the d ‐lysine biosynthetic pathway in the hyperthermophile Thermotoga maritima
Author(s) -
Miyamoto Tetsuya,
Katane Masumi,
Saitoh Yasuaki,
Sekine Masae,
Homma Hiroshi
Publication year - 2019
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.14720
Subject(s) - thermotoga maritima , hyperthermophile , lysine , chemistry , biochemistry , food science , biology , archaea , amino acid , escherichia coli , gene
Various d ‐amino acids are involved in peptidoglycan and biofilm metabolism in bacteria, suggesting that these compounds are necessary for successful adaptation to environmental changes. In addition to the conventional d ‐alanine ( d ‐Ala) and d ‐glutamate, the peptidoglycan of the hyperthermophilic bacterium Thermotoga maritima contains both l ‐lysine ( l ‐Lys) and d ‐Lys, but not meso ‐diaminopimelate ( meso ‐Dpm). d ‐Lys is an uncommon component of peptidoglycan, and its biosynthetic pathway remains unclear. In this study, we identified and characterized a novel Lys racemase ( TM 1597) and Dpm epimerase ( TM 1522) associated with the d ‐Lys biosynthetic pathway in T. maritima . The Lys racemase had a dimeric structure containing pyridoxal 5′‐phosphate as a cofactor. Among the amino acids, it exhibited the highest racemase activity toward d ‐ and l ‐Lys, and also had relatively high activity toward d ‐ and l ‐enantiomers of ornithine and Ala. The Dpm epimerase had the highest epimerization activity toward ll ‐ and meso ‐Dpm, and also measurably racemized certain amino acids, including Lys. These results suggest that Lys racemase contributes to production of d ‐Lys and d ‐Ala for use as peptidoglycan components, and that Dpm epimerase converts ll ‐Dpm to meso ‐Dpm, a precursor in the l ‐Lys biosynthetic pathway.