Biocatalytic application of halohydrin dehalogenases for production of chiral building blocks
The ability of enzymes to catalyse conversion of non-natural substrates has been used in synthetic organic chemistry, especially for synthesis of chiral molecules, and to date over 300 processes have been implemented in industry. However, the lack of suitable biocatalyst often makes a desirable biotransformation impossible. Recently, halohydrin dehalogenases have been discovered to catalyse several very attractive non-natural reactions. They can catalyse ring-opening of epoxides by using nucleophiles such as azide, cyanide, nitrite, cyanate and thiocyanate. These reactions represent an excellent method to furnish enantiopure building blocks. The access to such products by means of enzyme-catalysis is of great interest to the chemical and pharmaceutical industry. Target synthesis of the respective active enantiomer can improve the economics of the process and lead to reduced quantities applied thus reducing environmental impact.There are only several halohydrin dehalogenases discovered till now and only one has been sufficiently biocatalytically characterised. Now we want to expand the biocatalytic toolbox of halohydrin dehalogenases with a new enzyme from this class, an enzyme from Arthrobacter sp. On the basis of docking simulations and molecular modeling studies and with subsequent experimental synthesis and testing we expect to reveal the relationship between substrate structure, enzyme activity and enantioselectivity. Testing of a range of substrates and reaction conditions will deliver candidates for further development into preparative reactions with relevance to industrial application. Furthermore, it is to expect that this research besides revealing biocatalytic properties and applications of novel halohydrin dehalogenase will lay solid foundations for the protein engineering and design of improved enzyme variants in the future.