JF549-GGGG-Cys

JF549-GGGG-Cys: Fluorescent Oligoglycine Peptide for Sortase-Related Research

JF549-GGGG-Cys is a fluorescent oligoglycine-containing peptide prepared by conjugating GGGG-Cys with JF549-maleimide. The maleimide functional group reacts with the sulfhydryl group of the terminal cysteine, producing a covalent thioether-linked JF549 peptide conjugate.

This product combines a short glycine-rich peptide segment with a bright fluorescent label and may be used in the development of Sortase-related labeling systems, conjugation-method studies, fluorescence assays, and engineered biomolecular constructs.

Defined Cysteine-Maleimide Labeling

The cysteine residue in GGGG-Cys provides a defined thiol attachment site for JF549-maleimide. Reaction of the cysteine sulfhydryl group with the maleimide functionality produces a stable thioether-linked fluorescent conjugate.

Using cysteine as the chemical conjugation handle minimizes ambiguity regarding the position of the fluorescent label and allows the glycine-rich portion of the peptide to remain available for downstream assay design or molecular engineering.

Role of Oligoglycine Sequences in Sortase A Ligation

Sortase A-mediated ligation typically involves two complementary components: an LPXTG-containing donor substrate and a molecule bearing an accessible N-terminal oligoglycine nucleophile. Sortase A cleaves the LPXTG substrate between threonine and glycine and transfers the donor segment to the oligoglycine-containing acceptor.

The exact behavior of JF549-GGGG-Cys in a particular Sortase reaction depends on its orientation, terminal state, accessibility, and the design of the complete molecular construct. Researchers should verify that the glycine terminus required for their selected Sortase A system remains free and accessible.

Potential Applications

• Sortase-related assay development: Evaluation of fluorescent glycine-rich peptides in engineered ligation workflows.
• Fluorescent peptide tracing: Monitoring peptide localization, binding, uptake, or retention in compatible research systems.
• Conjugation chemistry studies: Investigation of maleimide-cysteine coupling, product stability, and linker behavior.
• Protein and biomolecule engineering: Incorporation into multicomponent constructs containing complementary Sortase recognition elements.
• Fluorescence microscopy: Visualization of peptide-containing constructs in biochemical, biomaterial, or cell-based studies.
• Flow cytometry and fluorescence detection: Analysis of fluorescently modified cells, particles, surfaces, or biomolecules.
• Biomaterial and surface functionalization: Development of fluorescent scaffolds, nanoparticles, hydrogels, or other engineered materials.
• Matched Sortase reagent development: Use with an appropriate LPETG-containing partner in customized conjugation systems.

JF549 Fluorophore

JF549 is a bright and photostable fluorescent dye used in microscopy, cell imaging, single-molecule studies, flow cytometry, and related fluorescence-based applications. The dye provides strong visible-range fluorescence and may serve as an alternative to conventional orange or yellow-red fluorophores in compatible detection systems.

Instrument settings, filters, excitation sources, and detection windows should be selected according to the specifications of the fluorophore and the requirements of the individual experiment.

Part of the LifeTein LPETG and Sortase Reagent Series

JF549-GGGG-Cys is offered as part of a related series of fluorescent peptides for Sortase A substrate research, ligation assay development, and site-specific biomolecule modification.

• JF549-LPETGG — a fluorescent LPETGG donor substrate labeled through the peptide's N-terminal amino group.
• JF549-Cys-LPETGG — an LPETGG donor substrate prepared by conjugating JF549-maleimide to an N-terminal cysteine.
• JF549-GGGG-Cys — the current glycine-rich fluorescent peptide, prepared through cysteine-maleimide conjugation.

Complementary Product Architecture

Custom Sortase Substrates and Oligoglycine Peptides

LifeTein provides custom synthesis of LPXTG donor peptides, oligoglycine-containing acceptor peptides, fluorescent conjugates, biotinylated peptides, spacer-modified substrates, and matched peptide sets for Sortase-mediated ligation.

Available customization may include alternative glycine lengths, reversed peptide orientation, N-terminal oligoglycine presentation, different fluorophores, Ahx or PEG spacers, terminal amidation, biotin, reactive groups, purity levels, and production scales.

Please contact LifeTein for technical review of the peptide orientation and terminal configuration required for your specific Sortase A reaction.

For research use only. Not for human, veterinary, diagnostic, therapeutic, or clinical use.