Discovery of an ʟ-amino acid ligase implicated in Staphylococcal sulfur amino acid metabolism

• DOI: 10.1016/j.jbc.2022.102392
• Publication Date: 2022-08-19T03:18:32Z
• Authors: Jordan L. Pederick; Aimee J. Horsfall; Blagojce Jovcevski‬; Jack Klose; Andrew D. Abell; Tara L. Pukala; John B. Bruning
• Keywords: Amino acid metabolism; Sulfur Metabolism

Enzymes involved in Staphylococcus aureus amino acid metabolism have recently gained traction as promising targets for the development of new antibiotics, however, not all aspects this process are understood. The ATP-grasp superfamily includes enzymes that predominantly catalyze ATP-dependent ligation various carboxylate and amine substrates. One subset, ʟ-amino ligases (LALs), primarily formation dipeptide products Gram-positive bacteria, their involvement S. has been investigated. Here, we present characterization putative enzyme (SAOUHSC_02373) from NCTC 8325 its identification a novel LAL. First, interrogated activity SAOUHSC_02373 against panel As result, identified an LAL with high selectivity ʟ-aspartate ʟ-methionine substrates, specifically forming ʟ-aspartyl-ʟ-methionine dipeptide. Thus, propose be assigned ʟ-aspartate-ʟ-methionine ligase (LdmS). To further understand unique activity, investigated mechanism LdmS by X-ray crystallography, molecular modeling, site-directed mutagenesis. Our results suggest shares similar to other but possesses distinctive active site architecture confers ʟ-Asp ʟ-Met Phylogenetic analysis revealed homologs highly conserved closely related Firmicutes. Subsequent genetic upstream ldmS operon several trans-acting regulatory elements associated control Met Cys metabolism. Together, these findings support role Staphylococcal sulfur