Visualizing thiazolidine ring formation in the reaction of D-cysteine and pyridoxal-5'-phosphate within L-cysteine desulfurase SufS.
Nakamura, R., Fujishiro, T.(2025) Biochem Biophys Res Commun 754: 151497-151497
- PubMed: 40020322 
- DOI: https://doi.org/10.1016/j.bbrc.2025.151497
- Primary Citation of Related Structures:  
7XEJ, 7XEK, 7XEL, 7XEN, 7YB3 - PubMed Abstract: 
The reactivity of pyridoxal-5'-phosphate (PLP) with cysteine and its derivatives has been of increasing interest because the corresponding product, a thiazolidine PLP-cysteine adduct, can be formed via PLP-dependent enzymatic and non-enzymatic reactions. Here, we report biochemical and X-ray crystallographic snapshots of thiazolidine formation in reaction of D-cysteine with PLP in SufS, a PLP-dependent L-cysteine desulfurase. By comparing L- and D-penicillamine-bound SufS showing no thiazolidine formation in the crystals with D-cysteine SufS, we proposed a thiazolidine formation mechanism with important factors: the polar environments provided by the carbonyl groups of Ala28-Ala29 and Lys224-mediated base catalysis for the nucleophilic thiolate of D-cysteine.
Organizational Affiliation: 
Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Japan.