Characterization of a novel moderate-substrate specificity amino acid racemase from the hyperthermophilic archaeon Thermococcus litoralis.
Biosci Biotechnol Biochem
; 85(7): 1650-1657, 2021 Jun 24.
Article
in En
| MEDLINE
| ID: mdl-33942867
ABSTRACT
The amino acid sequence of the OCC_10945 gene product from the hyperthermophilic archaeon Thermococcus litoralis DSM5473, originally annotated as γ-aminobutyrate aminotransferase, is highly similar to that of the uncharacterized pyridoxal 5'-phosphate (PLP)-dependent amino acid racemase from Pyrococcus horikoshii. The OCC_10945 enzyme was successfully overexpressed in Escherichia coli by coexpression with a chaperone protein. The purified enzyme demonstrated PLP-dependent amino acid racemase activity primarily toward Met and Leu. Although PLP contributed to enzyme stability, it only loosely bound to this enzyme. Enzyme activity was strongly inhibited by several metal ions, including Co2+ and Zn2+, and nonsubstrate amino acids such as l-Arg and l-Lys. These results suggest that the underlying PLP-binding and substrate recognition mechanisms in this enzyme are significantly different from those of the other archaeal and bacterial amino acid racemases. This is the first description of a novel PLP-dependent amino acid racemase with moderate substrate specificity in hyperthermophilic archaea.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Thermococcus
/
Archaeal Proteins
/
Amino Acid Isomerases
Language:
En
Journal:
Biosci Biotechnol Biochem
Journal subject:
BIOQUIMICA
/
BIOTECNOLOGIA
Year:
2021
Document type:
Article
Affiliation country:
Japan