Cloning and characterization of thermotolerant xylitol dehydrogenases from yeast Pichia angusta.

Biswas, Dipanwita and Datt, Manish and Ganesan, K and Mondal, Alok K (2010) Cloning and characterization of thermotolerant xylitol dehydrogenases from yeast Pichia angusta. Applied microbiology and biotechnology, 88 (6). pp. 1311-20. ISSN 1432-0614

PDF mondal10.pdf - Published Version Restricted to Registered users only Download (449Kb) | Request a copy

Abstract

Pichia angusta (syn. Hansenula polymorpha) represents one of the rare yeast that can grow and ferment both xylose and glucose at higher temperature (50°C). However, little is known about the enzymes involved in xylose utilization from this species. Previous studies indicated the presence of one xylose reductase and two xylitol dehydrogenase genes in P. angusta. In this study, we have expressed both xylitol dehydrogenases (PaXdh1p and PaXdh2p) in Escherichia coli and purified them as 6X-Histidine-tagged proteins. Biochemical characterization of the recombinant proteins reveals that both PaXdh1p and PaXdh2p are thermotolerant enzymes. PaXdh2p contains a catalytic and a structural Zn atom. However, the structural Zn atom is not present in PaXdh1p. Both enzymes also differ in their affinity for the substrate as well as in the catalytic efficiency. Through mutagenesis and modeling approaches, we have also identified residues important for catalysis and substrate binding.

Item Type:	Article
Additional Information:	Copyright of this article belongs to Springer Science
Uncontrolled Keywords:	Xylitol dehydrogenase . Medium-chain alcohol dehydrogenase . Thermotolerant enzyme . Pichia angusta
Subjects:	Q Science > QR Microbiology
Depositing User:	Dr. K.P.S.Sengar
Date Deposited:	08 Dec 2011 18:59
Last Modified:	02 Apr 2012 06:43
URI:	http://crdd.osdd.net/open/id/eprint/501

Actions (login required)

View Item