Download MendeleyStructural Basis for the Catalysis and Substrate Specificity of a LarA Racemase with a Broad Substrate Spectrum.
Gatreddi, S., Urdiain-Arraiza, J., Desguin, B., Hausinger, R.P., Hu, J.(2025) ACS Catal 15: 2857-2866
- PubMed: 40013250 Search on PubMedSearch on PubMed Central
- DOI: https://doi.org/10.1021/acscatal.4c07804
- Primary Citation Related Structures:
9EIA, 9EID, 9EIF - PubMed Abstract:
The LarA family consists of diverse racemases/epimerases that interconvert the diastereomers of α-hydroxyacids by using a nickel-pincer nucleotide (NPN) cofactor. The hidden redox reaction catalyzed by the NPN cofactor makes LarA enzymes attractive engineering targets for various applications. However, how a LarA enzyme binds its natural substrate and recognizes different α-hydroxyacids has not been elucidated. Here, we report three high-resolution structures of the enzyme-substrate complexes of a broad-spectrum LarA enzyme from Isosphaera pallida (LarA Ip ). The substrate binding mode reveals a near-optimal orientation and distance between the hydride donor and acceptor, consistent with an updated proton-coupled hydride transfer mechanism. The experimentally solved structures, together with the structural models of other LarA enzymes, lead to the identification of the residues/structural elements that are critically involved in the interactions with different α-hydroxyacids. Collectively, this work provides a structural basis for the catalysis and substrate specificity of the LarA enzymes.
- Department of Microbiology, Genetics, and Immunology, Michigan State University, East Lansing, Michigan 48824, United States.
Organizational Affiliation:
