A site-specific fluorogenic probe for protein disulfide isomerase A1

Protein disulfide isomerase A1 (PDIA1) is essential for catalyzing disulfide bond isomerization, ensuring proper protein folding, and maintaining cellular homeostasis. Dysregulation of PDIA1 function is implicated in various diseases, emphasizing the need for tools to study its activity dynamically and specifically. Despite this need, current methods lack the sensitivity and robustness required for reliable detection of PDIA1 activity.(57) RESULTS: We synthesized a series of vinyl sulfone-based fluorescent probes capable of covalently binding to thiol groups, triggering fluorescence activation. Among these, the probe LS exhibited outstanding performance, achieving a ∼18-fold fluorescence intensity increase upon binding to PDIA1. LS showed high specificity for PDIA1 by selectively targeting the cysteine residue at position 397 in its active site. The probe demonstrated rapid fluorescence activation with significant intensity enhancement within a short time. Furthermore, LS featured consistent excitation and emission wavelengths, making it ideal for fluorescence-based detection. (84) SIGNIFICANCE: The strong targeting ability, rapid response, and stability of LS provide a powerful platform for real-time, dynamic monitoring of PDIA1 activity. This probe holds significant promise for exploring PDIA1's roles in physiological and pathological processes and advancing research in PDIA1-associated diseases using vinyl sulfone-based fluorescent probes.(46).