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Characterization of the cupin‐type phosphoglucose isomerase from the hyperthermophilic archaeon Thermococcus litoralisa
Author(s) -
Jeong Jong-Jin,
Fushinobu Shinya,
Ito Sohei,
Jeon Beong-Sam,
Shoun Hirofumi,
Wakagi Takayoshi
Publication year - 2003
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(02)03900-5
Subject(s) - glucose 6 phosphate isomerase , biochemistry , enzyme , isomerase , thermococcus , chemistry , escherichia coli , histidine , circular dichroism , mutant , microbiology and biotechnology , biology , gene , archaea
The gene encoding phosphoglucose isomerase was cloned from Thermococcus litoralis , and functionally expressed in Escherichia coli . The purified enzyme, a homodimer of 21.5 kDa subunits, was biochemically characterized. The inhibition constants for four competitive inhibitors were determined. The enzyme contained 1.25 mol Fe and 0.24 mol Zn per dimer. The activity was enhanced by the addition of Fe 2+ , but inhibited by Zn 2+ and EDTA. Enzymes with mutations in conserved histidine and glutamate residues in their cupin motifs contained no metals, and showed large decreases in k cat . The circular dichroism spectra of the mutant enzymes and the wild type enzyme were essentially the same but with slight differences.