Structure and function of YcnD from Bacillus subtilis, a flavin-containing oxidoreductase
| Autor: | Karl Gruber, Thérésa Bridget Fitzpatrick, Christoph Kratky, Alexander Morokutti, Peter Macheroux, Andrzej Franciszek Lyskowski, Sonja Sollner, Eva Maria Pointner |
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| Jazyk: | angličtina |
| Rok vydání: | 2005 |
| Předmět: |
Models
Molecular Flavin Mononucleotide Stereochemistry Dimer Nuclear Magnetic Resonance Flavin group Bacillus subtilis Biochemistry Cofactor Bacterial Proteins/chemistry/metabolism chemistry.chemical_compound Structure-Activity Relationship Bacterial Proteins Oxidoreductase Models Cloning Molecular Nuclear Magnetic Resonance Biomolecular Bacillus subtilis/enzymology DNA Primers chemistry.chemical_classification biology Base Sequence Substrate (chemistry) Molecular Oxidoreductases/chemistry/metabolism biology.organism_classification Kinetics Enzyme chemistry biology.protein Flavin Mononucleotide/metabolism Oxidoreductases Bacteria Cloning Biomolecular Protein Binding |
| Zdroj: | Biochemistry, Vol. 44, No 42 (2005) pp. 13724-33 |
| ISSN: | 0006-2960 |
| Popis: | YcnD from the gram-positive bacterium Bacillus subtilis is a member of a family of bacterial proteins that act as NADH- and/or NADPH-dependent oxidoreductases. Here, we report for the first time on the biochemical characterization of the purified protein, demonstrating that YcnD is an FMN-containing enzyme that can be reduced by NADH or NADPH (Km = 6.4 and 4.4 microM, respectively). In the presence of free FMN as the electron-accepting substrate, the latter reductant showed a ping-pong Bi-Bi reaction mechanism, whereas utilization of NADH is competitively inhibited by this substrate. This finding suggests that NADPH is the physiological reductant of the enzyme. We also show that YcnD reduces nitro-organic compounds, chromate, and a series of azo dyes. The reduction of azo dyes appears to be mediated by free reduced FMN because the reaction is considerably slower in its absence. Structure determination by X-ray crystallography revealed that YcnD folds into a three layer alpha-beta-alpha sandwich strongly resembling the topology of the NADH oxidase superfamily. Similar to homologous bacterial oxidoreductase, YcnD forms homodimers with an extended dimer interface. The biochemical data and the structure are discussed in light of the putative physiological function of YcnD as an oxidoreductase delivering reduced FMN to enzymes that require the reduced cofactor for activity. |
| Databáze: | OpenAIRE |
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