title: Pcal_0111, a highly thermostable bifunctional fructose-1,6-bisphosphate aldolase/phosphatase from Pyrobaculum calidifontis.
abstract: Pyrobaculum calidifontis genome harbors an open reading frame Pcal_0111 annotated as fructose bisphosphate aldolase. Although the gene is annotated as fructose bisphosphate aldolase, it exhibits a high homology with previously reported fructose-1,6-bisphosphate aldolase/phosphatase from Thermoproteus neutrophilus. To examine the biochemical properties of Pcal_0111, we have cloned and expressed the gene in Escherichia coli. Purified recombinant Pcal_0111 catalyzed both phosphatase and aldolase reactions with specific activity values of 4 U and 1.3 U, respectively. These values are highest among the fructose 1,6-bisphosphatases/aldolases characterized from archaea. The enzyme activity increased linearly with the increase in temperature until 100 °C. Recombinant Pcal_0111 is highly stable with a half-life of 120 min at 100 °C. There was no significant change in the circular dichroism spectra of the protein up to 90 °C. The enzyme activity was not affected by AMP but strongly inhibited by ATP with an IC50value of 0.75 mM and mildly by ADP. High thermostability and inhibition by ATP make Pcal_0111 a unique fructose 1,6-bisphosphatase/aldolase.
authors.affiliation: School of Biological Sciences, University of the Punjab, Quaid-e-Azam Campus, Lahore, 54590, Pakistan.
authors.forename: Iram
authors.initials: I
authors.lastname: Aziz
authors.affiliation: School of Biological Sciences, University of the Punjab, Quaid-e-Azam Campus, Lahore, 54590, Pakistan. naeemrashid37@hotmail.com.
authors.forename: Naeem
authors.initials: N
authors.lastname: Rashid
authors.affiliation: School of Biological Sciences, University of the Punjab, Quaid-e-Azam Campus, Lahore, 54590, Pakistan.
authors.forename: Raza
authors.initials: R
authors.lastname: Ashraf
authors.affiliation: School of Biological Sciences, University of the Punjab, Quaid-e-Azam Campus, Lahore, 54590, Pakistan.
authors.forename: Qamar
authors.initials: Q
authors.lastname: Bashir
authors.affiliation: The Research Organization of Science and Technology, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan.
authors.forename: Tadayuki
authors.initials: T
authors.lastname: Imanaka
authors.affiliation: School of Biological Sciences, University of the Punjab, Quaid-e-Azam Campus, Lahore, 54590, Pakistan.|School of Biological Sciences, University of Southampton, Southampton, SO16 7PX, UK.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Akhtar
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D019843:Archaeal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004795:Enzyme Stability; D006597:Fructose-Bisphosphatase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005634:Fructose-Bisphosphate Aldolase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006358:Hot Temperature; D011489:Protein Denaturation; D041543:Pyrobaculum / Q000201:enzymology* / Q000235:genetics
chemical_list: D019843:Archaeal Proteins; D000255:Adenosine Triphosphate; D006597:Fructose-Bisphosphatase; D005634:Fructose-Bisphosphate Aldolase
keywords: Bifunctional; Fructose 1,6-bisphosphatase; Fructose 1,6-bisphosphate aldolase; Pyrobaculum calidifontis; Thermostable