4C5Z

Crystal structure of A. niger ochratoxinase

Summary for 4C5Z

• Entry DOI: 10.2210/pdb4c5z/pdb
• Related: 4C5Y 4C60 4C65
• Descriptor: OCHRATOXINASE (2 entities in total)
• Functional Keywords: hydrolase, metal-dependent amidohydrolase, ochratoxin a hydrolysis, amidohydrolase superfamily
• Biological source: ASPERGILLUS NIGER
• Total number of polymer chains: 2
• Total formula weight: 93293.66

Authors

Dobritzsch, D.,Wang, H.,Schneider, G.,Yu, S. (deposition date: 2013-09-17, release date: 2014-07-02, Last modification date: 2023-12-20)

Primary citation

Dobritzsch, D.,Wang, H.,Schneider, G.,Yu, S.
Structural and Functional Characterization of Ochratoxinase, a Novel Mycotoxin Degrading Enzyme.
Biochem.J., 462:441-, 2014

PubMed 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 Penicillium 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 Å) 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 β-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.

PubMed: 24947135
DOI: 10.1042/BJ20140382

Experimental method

X-RAY DIFFRACTION (2.5 Å)