CLONING OF THE PHYTASES FROM EMERICELLA-NIDULANS AND THE THERMOPHILICFUNGUS TALAROMYCES-THERMOPHILUS

Phytases (EC 3.1.3.8) belong to the family of histidine acid phosphata ses. We have cloned the phytases of the fungi Emericella nidulans and Talaromyces thermophilus. The putative enzyme encoded by the E. nidula ns sequence consists of 463 amino acids and has a M-r of 51785. The pr otein deduced from the T. thermophilus sequence consists of 466 amino acids corresponding to a M-r of 51450. Both predicted amino acid seque nces exhibited high identity (48% to 67%) to known phytases. This high level of identity allowed the modelling of all available fungal phyta ses based on the three-dimensional structure coordinates of the Asperg illus niger phytase. By this approach we identified 21 amino acids whi ch are conserved in fungal phyA phytases and are part of the residues forming the substrate pocket. Furthermore, potential glycosylation sit es were identified and compared between the aforementioned phytases an d the A. niger phytase. (C) 1997 Elsevier Science B.V.