5clo
Crystal structure of a 4-oxalocrotonate tautomerase mutant in complex with nitrostyrene at 2.3 Angstrom
Structural highlights
Function4OT1_PSEPU Catalyzes the ketonization of 2-hydroxymuconate stereoselectively to yield 2-oxo-3-hexenedioate.[1] Publication Abstract from PubMedThe Michael-type addition reaction is widely used in organic synthesis for carbon-carbon bond formation. However, biocatalytic methodologies for this type of reaction are scarce, which is related to the fact that enzymes naturally catalysing carbon-carbon bond-forming Michael-type additions are rare. A promising template to develop new biocatalysts for carbon-carbon bond formation is the enzyme 4-oxalocrotonate tautomerase, which exhibits promiscuous Michael-type addition activity. Here we present mutability landscapes for the expression, tautomerase and Michael-type addition activities, and enantioselectivity of 4-oxalocrotonate tautomerase. These maps of neutral, beneficial and detrimental amino acids for each residue position and enzyme property provide detailed insight into sequence-function relationships. This offers exciting opportunities for enzyme engineering, which is illustrated by the redesign of 4-oxalocrotonate tautomerase into two enantiocomplementary 'Michaelases'. These 'Michaelases' catalyse the asymmetric addition of acetaldehyde to various nitroolefins, providing access to both enantiomers of gamma-nitroaldehydes, which are important precursors for pharmaceutically active gamma-aminobutyric acid derivatives. Using mutability landscapes of a promiscuous tautomerase to guide the engineering of enantioselective Michaelases.,van der Meer JY, Poddar H, Baas BJ, Miao Y, Rahimi M, Kunzendorf A, van Merkerk R, Tepper PG, Geertsema EM, Thunnissen AM, Quax WJ, Poelarends GJ Nat Commun. 2016 Mar 8;7:10911. doi: 10.1038/ncomms10911. PMID:26952338[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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