Modifications | Staphylococcus aureus sortase A (SrtA) is a membrane-associated transpeptidase that plays a central role in bacterial virulence by covalently anchoring surface proteins to the peptidoglycan cell wall. By recognizing the conserved LPXTG sorting signal, SrtA cleaves between threonine and glycine and catalyzes the formation of an amide bond linking the target protein to the bacterial cell wall. This process is essential for bacterial adhesion, biofilm formation, immune evasion, and host colonization in both human and veterinary infections caused by S. aureus. Because sortase-mediated protein anchoring is required for pathogenicity and is conserved across many Gram-positive bacteria, SrtA has attracted significant interest as a target for anti-infective drug development, including small-molecule inhibitors and vaccine strategies designed to block surface protein display. Beyond its biological relevance, Sortase A has been widely adopted as a powerful biotechnology tool due to its high sequence specificity and mild reaction conditions. In vitro, Sortase A enables site-specific protein ligation, often referred to as sortase-mediated ligation (SML). The enzyme efficiently couples proteins or peptides bearing a C-terminal LPXTG (commonly LPETG) motif to substrates containing an N-terminal glycine or aminomethylene group. This chemistry has been exploited as a molecular “stapler” for precise protein labeling, conjugation, cyclization, and immobilization in solution or on living cell surfaces. Engineered variants such as the Sortase A pentamutant exhibit enhanced catalytic efficiency, making them particularly suitable for preparative and high-throughput applications. LifeTein’s Biotin-Ahx-LPETGS-NH₂ peptide is an ideal substrate for Sortase A–mediated conjugation workflows. When used in combination with recombinant Sortase A, this peptide enables site-specific biotinylation of proteins bearing N-terminal glycine motifs, producing homogeneous, well-defined conjugates. The Ahx spacer improves accessibility and reaction efficiency, while the biotin tag supports downstream applications, including affinity purification, ELISA, surface immobilization, and imaging. Together, Sortase A and Biotin-Ahx-LPETGS-NH₂ provide a robust, modular solution for controlled protein modification, making this combination especially attractive for researchers working in protein engineering, diagnostics, vaccine development, and biomolecular labeling. |
Scientific Background | Recombinant Staphylococcus aureus Sortase A is a 7-residue synthetic peptide with the sequence Arg-Glu-Leu-Ala-Thr-Glu-Asp. Biotin provides an affinity handle for streptavidin-based capture or detection; an Ahx spacer separates the peptide from an attached label or affinity handle; C-terminal amidation removes the terminal carboxylate charge. The sequence contains 1 Asp and 2 Glu residues, contributing anionic character near neutral pH. These sequence-derived properties describe the reagent chemically; no specific receptor, enzyme, pathway, disease association, or biological activity is assigned without product-specific experimental evidence. |
Experimental Notes | Sequence-derived chemical properties support reagent selection and experimental planning but do not establish biological function. Solubility, aggregation, adsorption, conjugation efficiency, and assay performance should be validated under the intended experimental conditions. |
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