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Structural and functional characterization of ochratoxinase, a novel mycotoxin-degrading enzyme.
- Source :
-
Biochemical Journal . 9/15/2014, Vol. 462 Issue 3, p441-452. 17p. - Publication Year :
- 2014
-
Abstract
- Ochratoxin, with ochratoxin A as the dominant form, is one of the five major mycotoxins most harmful to humans and animals. It is produced by Aspergillus and Pénicillium species and occurs in a wide range of agricultural products. Detoxification of contaminated food is a challenging health issue. In the present paper we report the identification, characterization and crystal structure (at 2.2 A) of a novel microbial ochratoxinase from Aspergillus niger. A putative amidase gene encoding a 480 amino acid polypeptide was cloned and homologously expressed in A. niger. The recombinant protein is N-terminally truncated, thermostable, has optimal activity at pH ~6 and 66°C, and is more efficient in ochratoxin A hydrolysis than carboxypeptidase A and Y, the two previously known enzymes capable of degrading this mycotoxin. The subunit of the homo-octameric enzyme folds into a two-domain structure characteristic of a metal dependent amidohydrolase, with a twisted TIM (triosephosphateisomerase)- barrel and a smaller ß-sandwich domain. The active site contains an aspartate residue for acid-base catalysis, and a carboxylated lysine and four histidine residues for binding of a binuclear metal centre. [ABSTRACT FROM AUTHOR]
- Subjects :
- *OCHRATOXINS
*MYCOTOXINS
*ASPERGILLUS
*PENICILLIUM
*FOOD contamination
*AMIDASES
Subjects
Details
- Language :
- English
- ISSN :
- 02646021
- Volume :
- 462
- Issue :
- 3
- Database :
- Academic Search Index
- Journal :
- Biochemical Journal
- Publication Type :
- Academic Journal
- Accession number :
- 97883634
- Full Text :
- https://doi.org/10.1042/BJ20140382