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FMN-dependent oligomerization of putative lactate oxidase from Pediococcus acidilactici

DOI: 10.1371/journal.pone.0223870 DOI Help

Authors: Yashwanth Ashok (University of Oulu) , Mirko M. Maksimainen (University of Oulu) , Tuija Kallio (University of Oulu) , Pekka Kilpeläinen (University of Oulu) , Lari Lehtiö (University of Oulu)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Plos One , VOL 15

State: Published (Approved)
Published: February 2020
Diamond Proposal Number(s): 19951

Open Access Open Access

Abstract: Lactate oxidases belong to a group of FMN-dependent enzymes and they catalyze a conversion of lactate to pyruvate with a release of hydrogen peroxide. Hydrogen peroxide is also utilized as a read out in biosensors to quantitate lactate levels in biological samples. Aerococcus viridans lactate oxidase is the best characterized lactate oxidase and our knowledge of lactate oxidases relies largely to studies conducted with that particular enzyme. Pediococcus acidilactici lactate oxidase is also commercially available for e.g. lactate measurements, but this enzyme has not been characterized in detail before. Here we report structural characterization of the recombinant enzyme and its co-factor dependent oligomerization. The crystal structures revealed two distinct conformations in the loop closing the active site, consistent with previous biochemical studies implicating the role of loop in catalysis. Despite the structural conservation of active site residues, we were not able to detect either oxidase or monooxygenase activity when L-lactate was used as a substrate. Pediococcus acidilactici lactate oxidase is therefore an example of a misannotation of an FMN-dependent enzyme, which catalyzes likely a so far unknown oxidation reaction.

Journal Keywords: Crystal structure; Enzyme structure; Glycerol; Monomers; Biochemical cofactors; Pyruvate; Melting; Enzymes

Subject Areas: Biology and Bio-materials


Instruments: I04-Macromolecular Crystallography

Other Facilities: ESRF

Documents:
journal.pone.0223870.pdf