8srw

Crystal structure of O-acetyl-L-serine sulfhydrylase A (CysK) from Staphylococcus aureus NCTC 8325 complexed with a modified peptide inhibitor

spinqualitylabelsall models 8srw, resolution 2.15Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8srw is a 8 chain structure with sequence from Staphylococcus aureus subsp. aureus NCTC 8325 and Synthetic construct. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.15Å Ligands: LLP, NAL Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q2G0Q8_STAA8 Publication Abstract from PubMed The pathway of bacterial cysteine biosynthesis is gaining traction for the development of antibiotic adjuvants. Bacterial cysteine biosynthesis is generally facilitated by two enzymes possessing O-acetyl-l-serine sulfhydrylases (OASS), CysK and CysM. In Staphylococcus aureus, there exists a single OASS homologue, SaCysK. Knockout of SaCysK was found to increase sensitivity to oxidative stress, making it a relevant target for inhibitor development. SaCysK also forms two functional complexes via interaction with the preceding enzyme in the pathway serine acetyltransferase (CysE) or the transcriptional regulator of cysteine metabolism (CymR). These interactions occur through insertion of a C-terminal peptide of CysE or CymR into the active site of SaCysK, inhibiting OASS activity, and therefore represent an excellent starting point for developing SaCysK inhibitors. Here, we detail the characterization of CysE and CymR-derived C-terminal peptides as inhibitors of SaCysK. Using a combination of X-ray crystallography, surface plasmon resonance, and enzyme inhibition assays, it was determined that the CymR-derived decapeptide forms extensive interactions with SaCysK and acts as a potent inhibitor (K(D) = 25 nM; IC(50) = 180 nM), making it a promising lead for the development of SaCysK inhibitors. To understand the determinants of this high-affinity interaction, the structure-activity relationships of 16 rationally designed peptides were also investigated. This identified that the C-terminal pentapeptide of CymR facilitates the high-affinity interaction with SaCysK and that subtle structural modification of the pentapeptide is possible without impacting potency. Ultimately, this work identified CymR pentapeptides as a promising scaffold for the development of antibiotic adjuvants targeting SaCysK. Identification of Cysteine Metabolism Regulator (CymR)-Derived Pentapeptides as Nanomolar Inhibitors of Staphylococcus aureus O-Acetyl-l-serine Sulfhydrylase (CysK).,Pederick JL, Vandborg BC, George A, Bovermann H, Boyd JM, Freundlich JS, Bruning JB ACS Infect Dis. 2025 Jan 10;11(1):238-248. doi: 10.1021/acsinfecdis.4c00832. Epub , 2024 Dec 20. PMID:39705018 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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