title: Cloning and characterization of the first actinomycete β-propeller phytase from Streptomyces sp. US42.
abstract: A gene encoding an extracellular phytase was cloned for the first time from an Actinomycete, Streptomyces sp. US42 and sequenced. The sequence of this gene revealed an encoded polypeptide (PHY US42) exhibiting one and six residues difference with the putative phytases of Streptomyces lividans TK24 and Streptomyces coelicolor A3(2), respectively. The molecular modeling of PHY US42 indicated that this phytase belongs to the group of β-propeller phytases that are usually calcium-dependent. PHY US42 was purified and characterized. Its activity was calcium-dependent and maximal at pH 7 and 65 °C. The enzyme was perfectly stable at pH ranging from 5 to 10 and its thermostability was greatly enhanced in the presence of calcium. Indeed, PHY US42 maintained 80% of activity after 10 min of incubation at 75 °C in the presence of 5 mM CaCl2. PHY US42 was also found to exhibit high stability after incubation at 37 °C for 1 h in the presence of bovine bile and digestive proteases like of pepsin, trypsin, and chymotrypsin. Considering its biochemical properties, PHY US42 could be used as feed additive in combination with an acid phytase for monogastric animals.
authors.affiliation: Laboratory of Microorganisms and Biomolecules, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia.|Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, University Paris-Sud, Orsay, France.
authors.forename: Ines
authors.initials: I
authors.lastname: Boukhris
authors.affiliation: Laboratory of Microorganisms and Biomolecules, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia.
authors.forename: Ameny
authors.initials: A
authors.lastname: Farhat-Khemakhem
authors.affiliation: Laboratory of Microorganisms and Biomolecules, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia.
authors.forename: Kameleddine
authors.initials: K
authors.lastname: Bouchaala
authors.affiliation: Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, University Paris-Sud, Orsay, France.
authors.forename: Marie-Joëlle
authors.initials: MJ
authors.lastname: Virolle
authors.affiliation: Laboratory of Microorganisms and Biomolecules, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia. hichem.chouayekh@cbs.rnrt.tn.
authors.forename: Hichem
authors.initials: H
authors.lastname: Chouayekh
mesh_terms: D010832:6-Phytase / Q000235:genetics* / Q000378:metabolism*; D000595:Amino Acid Sequence; D001483:Base Sequence; D002118:Calcium / Q000737:chemistry; D003001:Cloning, Molecular; D004271:DNA, Fungal / Q000235:genetics; D004795:Enzyme Stability; D017422:Sequence Analysis, DNA; D013302:Streptomyces / Q000201:enzymology* / Q000235:genetics*; D013379:Substrate Specificity
chemical_list: D004271:DNA, Fungal; D010832:6-Phytase; D002118:Calcium
keywords: Calcium-dependent; Feed additive; Streptomyces; β-propeller phytase