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Updated: Mar 26, 2026
13:59
Methods to Identify the NMR Resonances of the 13C-Dimethyl N-terminal Amine on Reductively Methylated Proteins
Published on: December 12, 2013
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Identification of imine reductase-specific sequence motifs
Silvia Fademrecht1, Philipp N Scheller1, Bettina M Nestl1
1Institute of Technical Biochemistry, University of Stuttgart, Allmandring 31, 70569 Stuttgart, Germany.
Proteins
|February 10, 2016
Summary
Imine reductases (IREDs) are key enzymes for producing chiral amines. This study analyzed 530 IREDs, revealing conserved regions and identifying key positions (139 and 194) crucial for stereoselectivity in these valuable biocatalysts.
Area of Science:
- Biocatalysis and Enzyme Engineering
- Organic Chemistry
- Biotechnology
Background:
- Chiral amines are essential building blocks in pharmaceuticals and agrochemicals.
- Imine reductases (IREDs) are recently discovered enzymes that stereoselectively reduce imines to chiral amines.
- Limited understanding exists regarding IRED reaction mechanisms, substrate specificity, and stereoselectivity.
Purpose of the Study:
- To gain insights into sequence-function relationships of IREDs.
- To establish a standardized numbering scheme for IREDs.
- To investigate the molecular basis of IRED stereoselectivity.
Main Methods:
- Systematic analysis of 530 putative IRED sequences.
- Establishment of the Imine Reductase Engineering Database (www.IRED.BioCatNet.de).
- Conservation analysis and identification of conserved motifs and key positions.
Main Results:
- A standard numbering scheme (based on R-IRED-Sk) was introduced.
- Highly conserved cofactor binding and hydrophobic substrate binding regions were identified.
- Two IRED-specific motifs and superfamily-specific conserved positions (139 and 194) related to stereoselectivity were discovered.
- A preference for NADPH cofactor was observed across all analyzed IREDs.
Conclusions:
- The study provides a deeper understanding of IREDs' sequence-function relationships.
- Positions 139 and 194 are identified as critical determinants of R- or S-selectivity in IREDs.
- The findings facilitate the engineering of IREDs for specific chiral amine synthesis.
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