Structural and Kinetic Properties of a beta-Hydroxyacid Dehydrogenase Involved in Nicotinate Fermentation.
Reitz, S., Alhapel, A., Essen, L.O., Pierik, A.J.(2008) J Mol Biol 382: 802-811
- PubMed: 18680749 
- DOI: https://doi.org/10.1016/j.jmb.2008.07.050
- Primary Citation of Related Structures:  
3CKY - PubMed Abstract: 
2-(Hydroxymethyl)glutarate dehydrogenase, the fourth enzyme of the anaerobic nicotinate fermentation pathway of Eubacterium barkeri, catalyzes the NADH-dependent conversion between (S)-2-formylglutarate and (S)-2-(hydroxymethyl)glutarate. As shown by its 2.3-A crystal structure, this enzyme is a novel member of the beta-hydroxyacid dehydrogenase family and adopts a tetrameric architecture with monomers interacting via their C-terminal catalytic domains. The NAD-binding domains protrude heterogeneously from the central, tetrameric core with domain rotation angles differing up to 12 degrees. Kinetic properties of the enzyme, including NADH inhibition constants, were determined. A strong NADH binding in contrast to weaker NAD(+) binding of the protein was inferred from fluorometrically determined binding constants for the dinucleotide cofactor. The data support either an Iso Ordered Bi Bi mechanism or a more common Ordered Bi Bi mechanism as found in other dehydrogenases.
Organizational Affiliation: 
Philipps-Universität Marburg, Fachbereich Chemie, Hans-Meerwein-Strasse, D-35032 Marburg, Germany.