Related Experiment Video
Updated: Jun 18, 2026
09:14
Enzymatic Cascade Reactions for the Synthesis of Chiral Amino Alcohols from L-lysine
Published on: February 16, 2018
Structural basis for chiral substrate recognition by two 2,3-butanediol dehydrogenases.
Masato Otagiri1, Sadaharu Ui, Yuhsuke Takusagawa
1Laboratory of Environmental Molecular Biology, RIKEN, Tsurumi-ward, Kanagawa, Japan.
FEBS Letters
|November 28, 2009
Summary
Researchers identified key residues in 2,3-butanediol dehydrogenase (BDH) enzymes that dictate their stereospecificity. Mutating specific active site residues in meso-BDH altered its specificity to match l-BDH, confirming their crucial role.
Area of Science:
- Enzymology
- Structural Biology
- Biochemistry
Background:
- 2,3-butanediol dehydrogenase (BDH) enzymes are crucial for NAD-dependent redox reactions.
- Homologous BDH enzymes exhibit distinct stereospecificities for substrates and products.
- Understanding the structural basis for differential stereospecificity is essential.
Purpose of the Study:
- To elucidate the structural mechanisms underlying the differential stereospecificities of homologous BDH enzymes.
- To identify key amino acid residues responsible for modulating enzyme stereospecificity.
Main Methods:
- Determined the crystal structure of l-BDH with a bound inhibitor at 2.0 Å resolution.
- Compared the inhibitor binding mode of l-BDH with that of meso-BDH.
- Performed site-directed mutagenesis on three active site residues of meso-BDH.
Main Results:
- Structural comparison revealed the critical role of a hydrogen bond from a conserved tryptophan residue (Trp192 in l-BDH).
- Mutagenesis of Trp190 in meso-BDH, corresponding to Trp192 in l-BDH, along with two other residues, successfully altered its stereospecificity.
- The modified meso-BDH exhibited stereospecificity similar to l-BDH.
Conclusions:
- Conserved residues, particularly tryptophan, play a pivotal role in determining the stereospecificity of homologous BDH enzymes.
- Site-directed mutagenesis is an effective tool for probing and modifying enzyme function.
- This study provides structural and functional insights into enzyme evolution and specificity.
More Related Videos
Related Concept Videos
02:05Prochirality
The concept of prochirality leads to the nomenclature of the individual faces of a molecule and plays a crucial role in the enantioselective reaction. It is a concept where two or more achiral molecules react to produce chiral products. A typical process is the reaction of an achiral ketone to generate a chiral alcohol. Here, the achiral reactant reacts with an achiral reducing agent, sodium borohydride, to generate an equimolar mixture of the chiral enantiomers of the product. For example, an...
02:34Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.
02:23SN2 Reaction: Stereochemistry
In an SN2 reaction, the nucleophilic attack on the substrate and departure of the leaving group occurs simultaneously through a transition state. As the nucleophile approaches the substrate from the back-side, the configuration of the substrate carbon changes from tetrahedral to trigonal bipyramidal and then back to tetrahedral, leading to an inversion in the configuration of the product.
If the substrate is an achiral molecule at the α-carbon, the inversion of configuration is not observed.
If the substrate is an achiral molecule at the α-carbon, the inversion of configuration is not observed.
02:25Molecules with Multiple Chiral Centers
Molecules that possess multiple chiral centers can afford a large number of stereoisomers. For instance, while some molecules like 2-butanol have one chiral center, defined as a tetrahedral carbon atom with four different substituents attached, several molecules like butane-2,3-diol have multiple chiral centers. A simple formula to predict the number of stereoisomers possible for a molecule with n chiral centers is 2n. However, there can be a lower number where some of the stereoisomers are...
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
02:36Regioselectivity and Stereochemistry of Hydroboration
A significant aspect of hydroboration–oxidation is the regio- and stereochemical outcome of the reaction.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.