Structural Insight into a Metal-Dependent Mutase Revealing an Arginine Residue-Covalently Mediated Interconversion between Nucleotide-Based Pyranose and Furanose

Furanoses are important building blocks in both primary and secondary metabolites, and they are biosynthesized by FAD-dependent or metal-dependent mutases. We report here the crystal structure of metal-dependent mutase MtdL that shows poor tertiary-structure similarity to other known enzymes. Molecular dynamics (MD) simulations, site-directed mutagenesis, and LC-MS/MS proteomics analysis identified key catalytic residues and support an Arg159-covalently mediated catalytic mechanism. Sequence alignment shows that these key residues are conserved in other metal-dependent mutases, suggesting they share a common catalytic paradigm. These results provide better understanding and facilitate the use of metal-dependent mutases in the generation of furanose-containing molecules.

Automated summary

In this study, the crystal structure of metal-dependent mutase MtdL is reported, which shows poor similarity to other known enzymes. Molecular dynamics simulations, site-directed mutagenesis, and proteomics analysis were used to identify key catalytic residues and support an Arg159-covalently mediated catalytic mechanism. Sequence alignment reveals conserved key residues in other metal-dependent mutases, suggesting a common catalytic paradigm. These results enhance our understanding and facilitate the use of metal-dependent mutases in the generation of furanose-containing molecules.