Biochemical and phylogenetic characterization of a novel terrestrial hyperthermophilic archaeon pertaining to the genus Pyrococcus from an Algerian hydrothermal hot spring

Extremophiles ◽  
2006 ◽  
Vol 11 (1) ◽  
pp. 65-73 ◽  
Author(s):  
Mouloud Kecha ◽  
Said Benallaoua ◽  
Jean Pierre Touzel ◽  
Roger Bonaly ◽  
Francis Duchiron
Keyword(s):  
Hot Spring ◽  
Hyperthermophilic Archaeon ◽  
Phylogenetic Characterization

scholarly journals Phylogenetic Characterization of BKH3 Bacterium Isolated from a Hot Spring Consortium of Bakreshwar (India) and Its Application

2016 ◽  
Vol 06 (06) ◽  
pp. 453-461 ◽  
Author(s):  
Biswadeep Chaudhuri ◽  
Nurul Alam ◽  
Manas Sarkar ◽  
Trinath Chowdhury ◽  
Brajadulal Chattopadhyay
Keyword(s):  
Hot Spring ◽  
Phylogenetic Characterization

Characterization of a novel moderate-substrate specificity amino acid racemase from the hyperthermophilic archaeon Thermococcus litoralis

2021 ◽  
Author(s):  
Ryushi Kawakami ◽  
Chinatsu Kinoshita ◽  
Tomoki Kawase ◽  
Mikio Sato ◽  
Junji Hayashi ◽  
...  
Keyword(s):  
Amino Acid ◽  
Substrate Specificity ◽  
Enzyme Stability ◽  
Hyperthermophilic Archaea ◽  
Thermococcus Litoralis ◽  
Hyperthermophilic Archaeon ◽  
Aminobutyrate Aminotransferase ◽  
Chaperone Protein ◽  
Amino Acid Racemase

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 5ʹ-phosphate (PLP)-dependent amino acid racemase from Pyrococcus horikoshii. The OCC_10945 enzyme was successfully overexpressed in Escherichia coli by co-expression 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 non-substrate 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.

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